mirror of
https://github.com/rust-lang/rust-analyzer
synced 2024-12-28 05:53:45 +00:00
8562 lines
344 KiB
Text
8562 lines
344 KiB
Text
use crate::ast::{AngleBracketedArgs, ParenthesizedArgs, AttrStyle, BareFnTy};
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use crate::ast::{GenericBound, TraitBoundModifier};
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use crate::ast::Unsafety;
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use crate::ast::{Mod, AnonConst, Arg, Arm, Guard, Attribute, BindingMode, TraitItemKind};
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use crate::ast::Block;
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use crate::ast::{BlockCheckMode, CaptureBy, Movability};
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use crate::ast::{Constness, Crate};
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use crate::ast::Defaultness;
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use crate::ast::EnumDef;
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use crate::ast::{Expr, ExprKind, RangeLimits};
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use crate::ast::{Field, FnDecl, FnHeader};
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use crate::ast::{ForeignItem, ForeignItemKind, FunctionRetTy};
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use crate::ast::{GenericParam, GenericParamKind};
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use crate::ast::GenericArg;
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use crate::ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind};
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use crate::ast::{Label, Lifetime, Lit, LitKind};
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use crate::ast::Local;
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use crate::ast::MacStmtStyle;
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use crate::ast::{Mac, Mac_, MacDelimiter};
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use crate::ast::{MutTy, Mutability};
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use crate::ast::{Pat, PatKind, PathSegment};
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use crate::ast::{PolyTraitRef, QSelf};
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use crate::ast::{Stmt, StmtKind};
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use crate::ast::{VariantData, StructField};
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use crate::ast::StrStyle;
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use crate::ast::SelfKind;
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use crate::ast::{TraitItem, TraitRef, TraitObjectSyntax};
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use crate::ast::{Ty, TyKind, TypeBinding, GenericBounds};
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use crate::ast::{Visibility, VisibilityKind, WhereClause, CrateSugar};
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use crate::ast::{UseTree, UseTreeKind};
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use crate::ast::{BinOpKind, UnOp};
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use crate::ast::{RangeEnd, RangeSyntax};
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use crate::{ast, attr};
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use crate::ext::base::DummyResult;
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use crate::source_map::{self, SourceMap, Spanned, respan};
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use crate::parse::{self, SeqSep, classify, token};
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use crate::parse::lexer::{TokenAndSpan, UnmatchedBrace};
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use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
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use crate::parse::token::DelimToken;
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use crate::parse::{new_sub_parser_from_file, ParseSess, Directory, DirectoryOwnership};
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use crate::util::parser::{AssocOp, Fixity};
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use crate::print::pprust;
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use crate::ptr::P;
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use crate::parse::PResult;
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use crate::ThinVec;
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use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
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use crate::symbol::{Symbol, keywords};
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use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
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use rustc_target::spec::abi::{self, Abi};
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use syntax_pos::{Span, MultiSpan, BytePos, FileName};
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use log::{debug, trace};
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use std::borrow::Cow;
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use std::cmp;
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use std::mem;
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use std::path::{self, Path, PathBuf};
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use std::slice;
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#[derive(Debug)]
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/// Whether the type alias or associated type is a concrete type or an existential type
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pub enum AliasKind {
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/// Just a new name for the same type
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Weak(P<Ty>),
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/// Only trait impls of the type will be usable, not the actual type itself
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Existential(GenericBounds),
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}
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bitflags::bitflags! {
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struct Restrictions: u8 {
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const STMT_EXPR = 1 << 0;
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const NO_STRUCT_LITERAL = 1 << 1;
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}
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}
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type ItemInfo = (Ident, ItemKind, Option<Vec<Attribute>>);
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/// Specifies how to parse a path.
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#[derive(Copy, Clone, PartialEq)]
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pub enum PathStyle {
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/// In some contexts, notably in expressions, paths with generic arguments are ambiguous
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/// with something else. For example, in expressions `segment < ....` can be interpreted
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/// as a comparison and `segment ( ....` can be interpreted as a function call.
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/// In all such contexts the non-path interpretation is preferred by default for practical
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/// reasons, but the path interpretation can be forced by the disambiguator `::`, e.g.
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/// `x<y>` - comparisons, `x::<y>` - unambiguously a path.
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Expr,
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/// In other contexts, notably in types, no ambiguity exists and paths can be written
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/// without the disambiguator, e.g., `x<y>` - unambiguously a path.
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/// Paths with disambiguators are still accepted, `x::<Y>` - unambiguously a path too.
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Type,
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/// A path with generic arguments disallowed, e.g., `foo::bar::Baz`, used in imports,
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/// visibilities or attributes.
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/// Technically, this variant is unnecessary and e.g., `Expr` can be used instead
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/// (paths in "mod" contexts have to be checked later for absence of generic arguments
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/// anyway, due to macros), but it is used to avoid weird suggestions about expected
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/// tokens when something goes wrong.
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Mod,
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}
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#[derive(Clone, Copy, PartialEq, Debug)]
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enum SemiColonMode {
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Break,
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Ignore,
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Comma,
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}
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#[derive(Clone, Copy, PartialEq, Debug)]
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enum BlockMode {
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Break,
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Ignore,
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}
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/// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
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/// dropped into the token stream, which happens while parsing the result of
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/// macro expansion). Placement of these is not as complex as I feared it would
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/// be. The important thing is to make sure that lookahead doesn't balk at
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/// `token::Interpolated` tokens.
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macro_rules! maybe_whole_expr {
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($p:expr) => {
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if let token::Interpolated(nt) = $p.token.clone() {
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match *nt {
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token::NtExpr(ref e) | token::NtLiteral(ref e) => {
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$p.bump();
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return Ok((*e).clone());
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}
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token::NtPath(ref path) => {
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$p.bump();
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let span = $p.span;
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let kind = ExprKind::Path(None, (*path).clone());
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return Ok($p.mk_expr(span, kind, ThinVec::new()));
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}
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token::NtBlock(ref block) => {
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$p.bump();
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let span = $p.span;
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let kind = ExprKind::Block((*block).clone(), None);
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return Ok($p.mk_expr(span, kind, ThinVec::new()));
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}
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_ => {},
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};
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}
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}
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}
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/// As maybe_whole_expr, but for things other than expressions
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macro_rules! maybe_whole {
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($p:expr, $constructor:ident, |$x:ident| $e:expr) => {
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if let token::Interpolated(nt) = $p.token.clone() {
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if let token::$constructor($x) = (*nt).clone() {
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$p.bump();
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return Ok($e);
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}
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}
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};
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}
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fn maybe_append(mut lhs: Vec<Attribute>, mut rhs: Option<Vec<Attribute>>) -> Vec<Attribute> {
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if let Some(ref mut rhs) = rhs {
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lhs.append(rhs);
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}
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lhs
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}
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#[derive(Debug, Clone, Copy, PartialEq)]
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enum PrevTokenKind {
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DocComment,
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Comma,
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Plus,
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Interpolated,
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Eof,
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Ident,
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Other,
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}
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trait RecoverQPath: Sized {
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const PATH_STYLE: PathStyle = PathStyle::Expr;
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fn to_ty(&self) -> Option<P<Ty>>;
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fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self;
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fn to_string(&self) -> String;
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}
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impl RecoverQPath for Ty {
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const PATH_STYLE: PathStyle = PathStyle::Type;
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fn to_ty(&self) -> Option<P<Ty>> {
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Some(P(self.clone()))
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}
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fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self {
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Self { span: path.span, node: TyKind::Path(qself, path), id: self.id }
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}
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fn to_string(&self) -> String {
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pprust::ty_to_string(self)
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}
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}
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impl RecoverQPath for Pat {
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fn to_ty(&self) -> Option<P<Ty>> {
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self.to_ty()
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}
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fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self {
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Self { span: path.span, node: PatKind::Path(qself, path), id: self.id }
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}
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fn to_string(&self) -> String {
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pprust::pat_to_string(self)
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}
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}
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impl RecoverQPath for Expr {
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fn to_ty(&self) -> Option<P<Ty>> {
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self.to_ty()
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}
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fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self {
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Self { span: path.span, node: ExprKind::Path(qself, path),
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id: self.id, attrs: self.attrs.clone() }
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}
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fn to_string(&self) -> String {
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pprust::expr_to_string(self)
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}
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}
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/* ident is handled by common.rs */
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#[derive(Clone)]
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pub struct Parser<'a> {
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pub sess: &'a ParseSess,
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/// the current token:
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pub token: token::Token,
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/// the span of the current token:
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pub span: Span,
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/// the span of the previous token:
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meta_var_span: Option<Span>,
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pub prev_span: Span,
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/// the previous token kind
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prev_token_kind: PrevTokenKind,
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restrictions: Restrictions,
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/// Used to determine the path to externally loaded source files
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crate directory: Directory<'a>,
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/// Whether to parse sub-modules in other files.
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pub recurse_into_file_modules: bool,
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/// Name of the root module this parser originated from. If `None`, then the
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/// name is not known. This does not change while the parser is descending
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/// into modules, and sub-parsers have new values for this name.
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pub root_module_name: Option<String>,
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crate expected_tokens: Vec<TokenType>,
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token_cursor: TokenCursor,
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desugar_doc_comments: bool,
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/// Whether we should configure out of line modules as we parse.
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pub cfg_mods: bool,
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/// This field is used to keep track of how many left angle brackets we have seen. This is
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/// required in order to detect extra leading left angle brackets (`<` characters) and error
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/// appropriately.
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///
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/// See the comments in the `parse_path_segment` function for more details.
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crate unmatched_angle_bracket_count: u32,
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crate max_angle_bracket_count: u32,
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/// List of all unclosed delimiters found by the lexer. If an entry is used for error recovery
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/// it gets removed from here. Every entry left at the end gets emitted as an independent
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/// error.
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crate unclosed_delims: Vec<UnmatchedBrace>,
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}
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#[derive(Clone)]
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struct TokenCursor {
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frame: TokenCursorFrame,
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stack: Vec<TokenCursorFrame>,
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}
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#[derive(Clone)]
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struct TokenCursorFrame {
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delim: token::DelimToken,
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span: DelimSpan,
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open_delim: bool,
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tree_cursor: tokenstream::Cursor,
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close_delim: bool,
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last_token: LastToken,
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}
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/// This is used in `TokenCursorFrame` above to track tokens that are consumed
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/// by the parser, and then that's transitively used to record the tokens that
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/// each parse AST item is created with.
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///
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/// Right now this has two states, either collecting tokens or not collecting
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/// tokens. If we're collecting tokens we just save everything off into a local
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/// `Vec`. This should eventually though likely save tokens from the original
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/// token stream and just use slicing of token streams to avoid creation of a
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/// whole new vector.
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///
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/// The second state is where we're passively not recording tokens, but the last
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/// token is still tracked for when we want to start recording tokens. This
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/// "last token" means that when we start recording tokens we'll want to ensure
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/// that this, the first token, is included in the output.
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///
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/// You can find some more example usage of this in the `collect_tokens` method
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/// on the parser.
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#[derive(Clone)]
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enum LastToken {
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Collecting(Vec<TreeAndJoint>),
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Was(Option<TreeAndJoint>),
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}
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impl TokenCursorFrame {
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fn new(sp: DelimSpan, delim: DelimToken, tts: &TokenStream) -> Self {
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TokenCursorFrame {
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delim: delim,
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span: sp,
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open_delim: delim == token::NoDelim,
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tree_cursor: tts.clone().into_trees(),
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close_delim: delim == token::NoDelim,
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last_token: LastToken::Was(None),
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}
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}
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}
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impl TokenCursor {
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fn next(&mut self) -> TokenAndSpan {
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loop {
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let tree = if !self.frame.open_delim {
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self.frame.open_delim = true;
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TokenTree::open_tt(self.frame.span.open, self.frame.delim)
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} else if let Some(tree) = self.frame.tree_cursor.next() {
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tree
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} else if !self.frame.close_delim {
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self.frame.close_delim = true;
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TokenTree::close_tt(self.frame.span.close, self.frame.delim)
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} else if let Some(frame) = self.stack.pop() {
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self.frame = frame;
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continue
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} else {
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return TokenAndSpan { tok: token::Eof, sp: syntax_pos::DUMMY_SP }
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};
|
||
|
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match self.frame.last_token {
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LastToken::Collecting(ref mut v) => v.push(tree.clone().into()),
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LastToken::Was(ref mut t) => *t = Some(tree.clone().into()),
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||
}
|
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|
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match tree {
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TokenTree::Token(sp, tok) => return TokenAndSpan { tok: tok, sp: sp },
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TokenTree::Delimited(sp, delim, tts) => {
|
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let frame = TokenCursorFrame::new(sp, delim, &tts);
|
||
self.stack.push(mem::replace(&mut self.frame, frame));
|
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}
|
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}
|
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}
|
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}
|
||
|
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fn next_desugared(&mut self) -> TokenAndSpan {
|
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let (sp, name) = match self.next() {
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TokenAndSpan { sp, tok: token::DocComment(name) } => (sp, name),
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tok => return tok,
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};
|
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|
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let stripped = strip_doc_comment_decoration(&name.as_str());
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||
|
||
// Searches for the occurrences of `"#*` and returns the minimum number of `#`s
|
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// required to wrap the text.
|
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let mut num_of_hashes = 0;
|
||
let mut count = 0;
|
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for ch in stripped.chars() {
|
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count = match ch {
|
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'"' => 1,
|
||
'#' if count > 0 => count + 1,
|
||
_ => 0,
|
||
};
|
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num_of_hashes = cmp::max(num_of_hashes, count);
|
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}
|
||
|
||
let delim_span = DelimSpan::from_single(sp);
|
||
let body = TokenTree::Delimited(
|
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delim_span,
|
||
token::Bracket,
|
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[TokenTree::Token(sp, token::Ident(ast::Ident::from_str("doc"), false)),
|
||
TokenTree::Token(sp, token::Eq),
|
||
TokenTree::Token(sp, token::Literal(
|
||
token::StrRaw(Symbol::intern(&stripped), num_of_hashes), None))
|
||
]
|
||
.iter().cloned().collect::<TokenStream>().into(),
|
||
);
|
||
|
||
self.stack.push(mem::replace(&mut self.frame, TokenCursorFrame::new(
|
||
delim_span,
|
||
token::NoDelim,
|
||
&if doc_comment_style(&name.as_str()) == AttrStyle::Inner {
|
||
[TokenTree::Token(sp, token::Pound), TokenTree::Token(sp, token::Not), body]
|
||
.iter().cloned().collect::<TokenStream>().into()
|
||
} else {
|
||
[TokenTree::Token(sp, token::Pound), body]
|
||
.iter().cloned().collect::<TokenStream>().into()
|
||
},
|
||
)));
|
||
|
||
self.next()
|
||
}
|
||
}
|
||
|
||
#[derive(Clone, PartialEq)]
|
||
crate enum TokenType {
|
||
Token(token::Token),
|
||
Keyword(keywords::Keyword),
|
||
Operator,
|
||
Lifetime,
|
||
Ident,
|
||
Path,
|
||
Type,
|
||
Const,
|
||
}
|
||
|
||
impl TokenType {
|
||
fn to_string(&self) -> String {
|
||
match *self {
|
||
TokenType::Token(ref t) => format!("`{}`", pprust::token_to_string(t)),
|
||
TokenType::Keyword(kw) => format!("`{}`", kw.name()),
|
||
TokenType::Operator => "an operator".to_string(),
|
||
TokenType::Lifetime => "lifetime".to_string(),
|
||
TokenType::Ident => "identifier".to_string(),
|
||
TokenType::Path => "path".to_string(),
|
||
TokenType::Type => "type".to_string(),
|
||
TokenType::Const => "const".to_string(),
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Returns `true` if `IDENT t` can start a type -- `IDENT::a::b`, `IDENT<u8, u8>`,
|
||
/// `IDENT<<u8 as Trait>::AssocTy>`.
|
||
///
|
||
/// Types can also be of the form `IDENT(u8, u8) -> u8`, however this assumes
|
||
/// that `IDENT` is not the ident of a fn trait.
|
||
fn can_continue_type_after_non_fn_ident(t: &token::Token) -> bool {
|
||
t == &token::ModSep || t == &token::Lt ||
|
||
t == &token::BinOp(token::Shl)
|
||
}
|
||
|
||
/// Information about the path to a module.
|
||
pub struct ModulePath {
|
||
name: String,
|
||
path_exists: bool,
|
||
pub result: Result<ModulePathSuccess, Error>,
|
||
}
|
||
|
||
pub struct ModulePathSuccess {
|
||
pub path: PathBuf,
|
||
pub directory_ownership: DirectoryOwnership,
|
||
warn: bool,
|
||
}
|
||
|
||
pub enum Error {
|
||
FileNotFoundForModule {
|
||
mod_name: String,
|
||
default_path: String,
|
||
secondary_path: String,
|
||
dir_path: String,
|
||
},
|
||
DuplicatePaths {
|
||
mod_name: String,
|
||
default_path: String,
|
||
secondary_path: String,
|
||
},
|
||
UselessDocComment,
|
||
InclusiveRangeWithNoEnd,
|
||
}
|
||
|
||
impl Error {
|
||
fn span_err<S: Into<MultiSpan>>(self,
|
||
sp: S,
|
||
handler: &errors::Handler) -> DiagnosticBuilder<'_> {
|
||
match self {
|
||
Error::FileNotFoundForModule { ref mod_name,
|
||
ref default_path,
|
||
ref secondary_path,
|
||
ref dir_path } => {
|
||
let mut err = struct_span_err!(handler, sp, E0583,
|
||
"file not found for module `{}`", mod_name);
|
||
err.help(&format!("name the file either {} or {} inside the directory \"{}\"",
|
||
default_path,
|
||
secondary_path,
|
||
dir_path));
|
||
err
|
||
}
|
||
Error::DuplicatePaths { ref mod_name, ref default_path, ref secondary_path } => {
|
||
let mut err = struct_span_err!(handler, sp, E0584,
|
||
"file for module `{}` found at both {} and {}",
|
||
mod_name,
|
||
default_path,
|
||
secondary_path);
|
||
err.help("delete or rename one of them to remove the ambiguity");
|
||
err
|
||
}
|
||
Error::UselessDocComment => {
|
||
let mut err = struct_span_err!(handler, sp, E0585,
|
||
"found a documentation comment that doesn't document anything");
|
||
err.help("doc comments must come before what they document, maybe a comment was \
|
||
intended with `//`?");
|
||
err
|
||
}
|
||
Error::InclusiveRangeWithNoEnd => {
|
||
let mut err = struct_span_err!(handler, sp, E0586,
|
||
"inclusive range with no end");
|
||
err.help("inclusive ranges must be bounded at the end (`..=b` or `a..=b`)");
|
||
err
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
enum LhsExpr {
|
||
NotYetParsed,
|
||
AttributesParsed(ThinVec<Attribute>),
|
||
AlreadyParsed(P<Expr>),
|
||
}
|
||
|
||
impl From<Option<ThinVec<Attribute>>> for LhsExpr {
|
||
fn from(o: Option<ThinVec<Attribute>>) -> Self {
|
||
if let Some(attrs) = o {
|
||
LhsExpr::AttributesParsed(attrs)
|
||
} else {
|
||
LhsExpr::NotYetParsed
|
||
}
|
||
}
|
||
}
|
||
|
||
impl From<P<Expr>> for LhsExpr {
|
||
fn from(expr: P<Expr>) -> Self {
|
||
LhsExpr::AlreadyParsed(expr)
|
||
}
|
||
}
|
||
|
||
/// Creates a placeholder argument.
|
||
fn dummy_arg(span: Span) -> Arg {
|
||
let ident = Ident::new(keywords::Invalid.name(), span);
|
||
let pat = P(Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), ident, None),
|
||
span,
|
||
});
|
||
let ty = Ty {
|
||
node: TyKind::Err,
|
||
span,
|
||
id: ast::DUMMY_NODE_ID
|
||
};
|
||
Arg { ty: P(ty), pat: pat, id: ast::DUMMY_NODE_ID }
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug)]
|
||
enum TokenExpectType {
|
||
Expect,
|
||
NoExpect,
|
||
}
|
||
|
||
impl<'a> Parser<'a> {
|
||
pub fn new(sess: &'a ParseSess,
|
||
tokens: TokenStream,
|
||
directory: Option<Directory<'a>>,
|
||
recurse_into_file_modules: bool,
|
||
desugar_doc_comments: bool)
|
||
-> Self {
|
||
let mut parser = Parser {
|
||
sess,
|
||
token: token::Whitespace,
|
||
span: syntax_pos::DUMMY_SP,
|
||
prev_span: syntax_pos::DUMMY_SP,
|
||
meta_var_span: None,
|
||
prev_token_kind: PrevTokenKind::Other,
|
||
restrictions: Restrictions::empty(),
|
||
recurse_into_file_modules,
|
||
directory: Directory {
|
||
path: Cow::from(PathBuf::new()),
|
||
ownership: DirectoryOwnership::Owned { relative: None }
|
||
},
|
||
root_module_name: None,
|
||
expected_tokens: Vec::new(),
|
||
token_cursor: TokenCursor {
|
||
frame: TokenCursorFrame::new(
|
||
DelimSpan::dummy(),
|
||
token::NoDelim,
|
||
&tokens.into(),
|
||
),
|
||
stack: Vec::new(),
|
||
},
|
||
desugar_doc_comments,
|
||
cfg_mods: true,
|
||
unmatched_angle_bracket_count: 0,
|
||
max_angle_bracket_count: 0,
|
||
unclosed_delims: Vec::new(),
|
||
};
|
||
|
||
let tok = parser.next_tok();
|
||
parser.token = tok.tok;
|
||
parser.span = tok.sp;
|
||
|
||
if let Some(directory) = directory {
|
||
parser.directory = directory;
|
||
} else if !parser.span.is_dummy() {
|
||
if let FileName::Real(mut path) = sess.source_map().span_to_unmapped_path(parser.span) {
|
||
path.pop();
|
||
parser.directory.path = Cow::from(path);
|
||
}
|
||
}
|
||
|
||
parser.process_potential_macro_variable();
|
||
parser
|
||
}
|
||
|
||
fn next_tok(&mut self) -> TokenAndSpan {
|
||
let mut next = if self.desugar_doc_comments {
|
||
self.token_cursor.next_desugared()
|
||
} else {
|
||
self.token_cursor.next()
|
||
};
|
||
if next.sp.is_dummy() {
|
||
// Tweak the location for better diagnostics, but keep syntactic context intact.
|
||
next.sp = self.prev_span.with_ctxt(next.sp.ctxt());
|
||
}
|
||
next
|
||
}
|
||
|
||
/// Converts the current token to a string using `self`'s reader.
|
||
pub fn this_token_to_string(&self) -> String {
|
||
pprust::token_to_string(&self.token)
|
||
}
|
||
|
||
fn token_descr(&self) -> Option<&'static str> {
|
||
Some(match &self.token {
|
||
t if t.is_special_ident() => "reserved identifier",
|
||
t if t.is_used_keyword() => "keyword",
|
||
t if t.is_unused_keyword() => "reserved keyword",
|
||
token::DocComment(..) => "doc comment",
|
||
_ => return None,
|
||
})
|
||
}
|
||
|
||
fn this_token_descr(&self) -> String {
|
||
if let Some(prefix) = self.token_descr() {
|
||
format!("{} `{}`", prefix, self.this_token_to_string())
|
||
} else {
|
||
format!("`{}`", self.this_token_to_string())
|
||
}
|
||
}
|
||
|
||
fn unexpected_last<T>(&self, t: &token::Token) -> PResult<'a, T> {
|
||
let token_str = pprust::token_to_string(t);
|
||
Err(self.span_fatal(self.prev_span, &format!("unexpected token: `{}`", token_str)))
|
||
}
|
||
|
||
crate fn unexpected<T>(&mut self) -> PResult<'a, T> {
|
||
match self.expect_one_of(&[], &[]) {
|
||
Err(e) => Err(e),
|
||
Ok(_) => unreachable!(),
|
||
}
|
||
}
|
||
|
||
/// Expects and consumes the token `t`. Signals an error if the next token is not `t`.
|
||
pub fn expect(&mut self, t: &token::Token) -> PResult<'a, bool /* recovered */> {
|
||
if self.expected_tokens.is_empty() {
|
||
if self.token == *t {
|
||
self.bump();
|
||
Ok(false)
|
||
} else {
|
||
let token_str = pprust::token_to_string(t);
|
||
let this_token_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!("expected `{}`, found {}",
|
||
token_str,
|
||
this_token_str));
|
||
|
||
let sp = if self.token == token::Token::Eof {
|
||
// EOF, don't want to point at the following char, but rather the last token
|
||
self.prev_span
|
||
} else {
|
||
self.sess.source_map().next_point(self.prev_span)
|
||
};
|
||
let label_exp = format!("expected `{}`", token_str);
|
||
match self.recover_closing_delimiter(&[t.clone()], err) {
|
||
Err(e) => err = e,
|
||
Ok(recovered) => {
|
||
return Ok(recovered);
|
||
}
|
||
}
|
||
let cm = self.sess.source_map();
|
||
match (cm.lookup_line(self.span.lo()), cm.lookup_line(sp.lo())) {
|
||
(Ok(ref a), Ok(ref b)) if a.line == b.line => {
|
||
// When the spans are in the same line, it means that the only content
|
||
// between them is whitespace, point only at the found token.
|
||
err.span_label(self.span, label_exp);
|
||
}
|
||
_ => {
|
||
err.span_label(sp, label_exp);
|
||
err.span_label(self.span, "unexpected token");
|
||
}
|
||
}
|
||
Err(err)
|
||
}
|
||
} else {
|
||
self.expect_one_of(slice::from_ref(t), &[])
|
||
}
|
||
}
|
||
|
||
fn recover_closing_delimiter(
|
||
&mut self,
|
||
tokens: &[token::Token],
|
||
mut err: DiagnosticBuilder<'a>,
|
||
) -> PResult<'a, bool> {
|
||
let mut pos = None;
|
||
// we want to use the last closing delim that would apply
|
||
for (i, unmatched) in self.unclosed_delims.iter().enumerate().rev() {
|
||
if tokens.contains(&token::CloseDelim(unmatched.expected_delim))
|
||
&& Some(self.span) > unmatched.unclosed_span
|
||
{
|
||
pos = Some(i);
|
||
}
|
||
}
|
||
match pos {
|
||
Some(pos) => {
|
||
// Recover and assume that the detected unclosed delimiter was meant for
|
||
// this location. Emit the diagnostic and act as if the delimiter was
|
||
// present for the parser's sake.
|
||
|
||
// Don't attempt to recover from this unclosed delimiter more than once.
|
||
let unmatched = self.unclosed_delims.remove(pos);
|
||
let delim = TokenType::Token(token::CloseDelim(unmatched.expected_delim));
|
||
|
||
// We want to suggest the inclusion of the closing delimiter where it makes
|
||
// the most sense, which is immediately after the last token:
|
||
//
|
||
// {foo(bar {}}
|
||
// - ^
|
||
// | |
|
||
// | help: `)` may belong here (FIXME: #58270)
|
||
// |
|
||
// unclosed delimiter
|
||
if let Some(sp) = unmatched.unclosed_span {
|
||
err.span_label(sp, "unclosed delimiter");
|
||
}
|
||
err.span_suggestion_short(
|
||
self.sess.source_map().next_point(self.prev_span),
|
||
&format!("{} may belong here", delim.to_string()),
|
||
delim.to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
err.emit();
|
||
self.expected_tokens.clear(); // reduce errors
|
||
Ok(true)
|
||
}
|
||
_ => Err(err),
|
||
}
|
||
}
|
||
|
||
/// Expect next token to be edible or inedible token. If edible,
|
||
/// then consume it; if inedible, then return without consuming
|
||
/// anything. Signal a fatal error if next token is unexpected.
|
||
pub fn expect_one_of(
|
||
&mut self,
|
||
edible: &[token::Token],
|
||
inedible: &[token::Token],
|
||
) -> PResult<'a, bool /* recovered */> {
|
||
fn tokens_to_string(tokens: &[TokenType]) -> String {
|
||
let mut i = tokens.iter();
|
||
// This might be a sign we need a connect method on Iterator.
|
||
let b = i.next()
|
||
.map_or(String::new(), |t| t.to_string());
|
||
i.enumerate().fold(b, |mut b, (i, a)| {
|
||
if tokens.len() > 2 && i == tokens.len() - 2 {
|
||
b.push_str(", or ");
|
||
} else if tokens.len() == 2 && i == tokens.len() - 2 {
|
||
b.push_str(" or ");
|
||
} else {
|
||
b.push_str(", ");
|
||
}
|
||
b.push_str(&a.to_string());
|
||
b
|
||
})
|
||
}
|
||
if edible.contains(&self.token) {
|
||
self.bump();
|
||
Ok(false)
|
||
} else if inedible.contains(&self.token) {
|
||
// leave it in the input
|
||
Ok(false)
|
||
} else {
|
||
let mut expected = edible.iter()
|
||
.map(|x| TokenType::Token(x.clone()))
|
||
.chain(inedible.iter().map(|x| TokenType::Token(x.clone())))
|
||
.chain(self.expected_tokens.iter().cloned())
|
||
.collect::<Vec<_>>();
|
||
expected.sort_by_cached_key(|x| x.to_string());
|
||
expected.dedup();
|
||
let expect = tokens_to_string(&expected[..]);
|
||
let actual = self.this_token_to_string();
|
||
let (msg_exp, (label_sp, label_exp)) = if expected.len() > 1 {
|
||
let short_expect = if expected.len() > 6 {
|
||
format!("{} possible tokens", expected.len())
|
||
} else {
|
||
expect.clone()
|
||
};
|
||
(format!("expected one of {}, found `{}`", expect, actual),
|
||
(self.sess.source_map().next_point(self.prev_span),
|
||
format!("expected one of {} here", short_expect)))
|
||
} else if expected.is_empty() {
|
||
(format!("unexpected token: `{}`", actual),
|
||
(self.prev_span, "unexpected token after this".to_string()))
|
||
} else {
|
||
(format!("expected {}, found `{}`", expect, actual),
|
||
(self.sess.source_map().next_point(self.prev_span),
|
||
format!("expected {} here", expect)))
|
||
};
|
||
let mut err = self.fatal(&msg_exp);
|
||
if self.token.is_ident_named("and") {
|
||
err.span_suggestion_short(
|
||
self.span,
|
||
"use `&&` instead of `and` for the boolean operator",
|
||
"&&".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
if self.token.is_ident_named("or") {
|
||
err.span_suggestion_short(
|
||
self.span,
|
||
"use `||` instead of `or` for the boolean operator",
|
||
"||".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
let sp = if self.token == token::Token::Eof {
|
||
// This is EOF, don't want to point at the following char, but rather the last token
|
||
self.prev_span
|
||
} else {
|
||
label_sp
|
||
};
|
||
match self.recover_closing_delimiter(&expected.iter().filter_map(|tt| match tt {
|
||
TokenType::Token(t) => Some(t.clone()),
|
||
_ => None,
|
||
}).collect::<Vec<_>>(), err) {
|
||
Err(e) => err = e,
|
||
Ok(recovered) => {
|
||
return Ok(recovered);
|
||
}
|
||
}
|
||
|
||
let cm = self.sess.source_map();
|
||
match (cm.lookup_line(self.span.lo()), cm.lookup_line(sp.lo())) {
|
||
(Ok(ref a), Ok(ref b)) if a.line == b.line => {
|
||
// When the spans are in the same line, it means that the only content between
|
||
// them is whitespace, point at the found token in that case:
|
||
//
|
||
// X | () => { syntax error };
|
||
// | ^^^^^ expected one of 8 possible tokens here
|
||
//
|
||
// instead of having:
|
||
//
|
||
// X | () => { syntax error };
|
||
// | -^^^^^ unexpected token
|
||
// | |
|
||
// | expected one of 8 possible tokens here
|
||
err.span_label(self.span, label_exp);
|
||
}
|
||
_ if self.prev_span == syntax_pos::DUMMY_SP => {
|
||
// Account for macro context where the previous span might not be
|
||
// available to avoid incorrect output (#54841).
|
||
err.span_label(self.span, "unexpected token");
|
||
}
|
||
_ => {
|
||
err.span_label(sp, label_exp);
|
||
err.span_label(self.span, "unexpected token");
|
||
}
|
||
}
|
||
Err(err)
|
||
}
|
||
}
|
||
|
||
/// Returns the span of expr, if it was not interpolated or the span of the interpolated token.
|
||
fn interpolated_or_expr_span(&self,
|
||
expr: PResult<'a, P<Expr>>)
|
||
-> PResult<'a, (Span, P<Expr>)> {
|
||
expr.map(|e| {
|
||
if self.prev_token_kind == PrevTokenKind::Interpolated {
|
||
(self.prev_span, e)
|
||
} else {
|
||
(e.span, e)
|
||
}
|
||
})
|
||
}
|
||
|
||
fn expected_ident_found(&self) -> DiagnosticBuilder<'a> {
|
||
let mut err = self.struct_span_err(self.span,
|
||
&format!("expected identifier, found {}",
|
||
self.this_token_descr()));
|
||
if let token::Ident(ident, false) = &self.token {
|
||
if ident.is_reserved() && !ident.is_path_segment_keyword() &&
|
||
ident.name != keywords::Underscore.name()
|
||
{
|
||
err.span_suggestion(
|
||
self.span,
|
||
"you can escape reserved keywords to use them as identifiers",
|
||
format!("r#{}", ident),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
}
|
||
if let Some(token_descr) = self.token_descr() {
|
||
err.span_label(self.span, format!("expected identifier, found {}", token_descr));
|
||
} else {
|
||
err.span_label(self.span, "expected identifier");
|
||
if self.token == token::Comma && self.look_ahead(1, |t| t.is_ident()) {
|
||
err.span_suggestion(
|
||
self.span,
|
||
"remove this comma",
|
||
String::new(),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
}
|
||
}
|
||
err
|
||
}
|
||
|
||
pub fn parse_ident(&mut self) -> PResult<'a, ast::Ident> {
|
||
self.parse_ident_common(true)
|
||
}
|
||
|
||
fn parse_ident_common(&mut self, recover: bool) -> PResult<'a, ast::Ident> {
|
||
match self.token {
|
||
token::Ident(ident, _) => {
|
||
if self.token.is_reserved_ident() {
|
||
let mut err = self.expected_ident_found();
|
||
if recover {
|
||
err.emit();
|
||
} else {
|
||
return Err(err);
|
||
}
|
||
}
|
||
let span = self.span;
|
||
self.bump();
|
||
Ok(Ident::new(ident.name, span))
|
||
}
|
||
_ => {
|
||
Err(if self.prev_token_kind == PrevTokenKind::DocComment {
|
||
self.span_fatal_err(self.prev_span, Error::UselessDocComment)
|
||
} else {
|
||
self.expected_ident_found()
|
||
})
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Checks if the next token is `tok`, and returns `true` if so.
|
||
///
|
||
/// This method will automatically add `tok` to `expected_tokens` if `tok` is not
|
||
/// encountered.
|
||
crate fn check(&mut self, tok: &token::Token) -> bool {
|
||
let is_present = self.token == *tok;
|
||
if !is_present { self.expected_tokens.push(TokenType::Token(tok.clone())); }
|
||
is_present
|
||
}
|
||
|
||
/// Consumes a token 'tok' if it exists. Returns whether the given token was present.
|
||
pub fn eat(&mut self, tok: &token::Token) -> bool {
|
||
let is_present = self.check(tok);
|
||
if is_present { self.bump() }
|
||
is_present
|
||
}
|
||
|
||
fn check_keyword(&mut self, kw: keywords::Keyword) -> bool {
|
||
self.expected_tokens.push(TokenType::Keyword(kw));
|
||
self.token.is_keyword(kw)
|
||
}
|
||
|
||
/// If the next token is the given keyword, eats it and returns
|
||
/// `true`. Otherwise, returns `false`.
|
||
pub fn eat_keyword(&mut self, kw: keywords::Keyword) -> bool {
|
||
if self.check_keyword(kw) {
|
||
self.bump();
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
fn eat_keyword_noexpect(&mut self, kw: keywords::Keyword) -> bool {
|
||
if self.token.is_keyword(kw) {
|
||
self.bump();
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
/// If the given word is not a keyword, signals an error.
|
||
/// If the next token is not the given word, signals an error.
|
||
/// Otherwise, eats it.
|
||
fn expect_keyword(&mut self, kw: keywords::Keyword) -> PResult<'a, ()> {
|
||
if !self.eat_keyword(kw) {
|
||
self.unexpected()
|
||
} else {
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
fn check_ident(&mut self) -> bool {
|
||
if self.token.is_ident() {
|
||
true
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Ident);
|
||
false
|
||
}
|
||
}
|
||
|
||
fn check_path(&mut self) -> bool {
|
||
if self.token.is_path_start() {
|
||
true
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Path);
|
||
false
|
||
}
|
||
}
|
||
|
||
fn check_type(&mut self) -> bool {
|
||
if self.token.can_begin_type() {
|
||
true
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Type);
|
||
false
|
||
}
|
||
}
|
||
|
||
fn check_const_arg(&mut self) -> bool {
|
||
if self.token.can_begin_const_arg() {
|
||
true
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Const);
|
||
false
|
||
}
|
||
}
|
||
|
||
/// Expects and consumes a `+`. if `+=` is seen, replaces it with a `=`
|
||
/// and continues. If a `+` is not seen, returns `false`.
|
||
///
|
||
/// This is used when token-splitting `+=` into `+`.
|
||
/// See issue #47856 for an example of when this may occur.
|
||
fn eat_plus(&mut self) -> bool {
|
||
self.expected_tokens.push(TokenType::Token(token::BinOp(token::Plus)));
|
||
match self.token {
|
||
token::BinOp(token::Plus) => {
|
||
self.bump();
|
||
true
|
||
}
|
||
token::BinOpEq(token::Plus) => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
self.bump_with(token::Eq, span);
|
||
true
|
||
}
|
||
_ => false,
|
||
}
|
||
}
|
||
|
||
|
||
/// Checks to see if the next token is either `+` or `+=`.
|
||
/// Otherwise returns `false`.
|
||
fn check_plus(&mut self) -> bool {
|
||
if self.token.is_like_plus() {
|
||
true
|
||
}
|
||
else {
|
||
self.expected_tokens.push(TokenType::Token(token::BinOp(token::Plus)));
|
||
false
|
||
}
|
||
}
|
||
|
||
/// Expects and consumes an `&`. If `&&` is seen, replaces it with a single
|
||
/// `&` and continues. If an `&` is not seen, signals an error.
|
||
fn expect_and(&mut self) -> PResult<'a, ()> {
|
||
self.expected_tokens.push(TokenType::Token(token::BinOp(token::And)));
|
||
match self.token {
|
||
token::BinOp(token::And) => {
|
||
self.bump();
|
||
Ok(())
|
||
}
|
||
token::AndAnd => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Ok(self.bump_with(token::BinOp(token::And), span))
|
||
}
|
||
_ => self.unexpected()
|
||
}
|
||
}
|
||
|
||
/// Expects and consumes an `|`. If `||` is seen, replaces it with a single
|
||
/// `|` and continues. If an `|` is not seen, signals an error.
|
||
fn expect_or(&mut self) -> PResult<'a, ()> {
|
||
self.expected_tokens.push(TokenType::Token(token::BinOp(token::Or)));
|
||
match self.token {
|
||
token::BinOp(token::Or) => {
|
||
self.bump();
|
||
Ok(())
|
||
}
|
||
token::OrOr => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Ok(self.bump_with(token::BinOp(token::Or), span))
|
||
}
|
||
_ => self.unexpected()
|
||
}
|
||
}
|
||
|
||
fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<ast::Name>) {
|
||
match suffix {
|
||
None => {/* everything ok */}
|
||
Some(suf) => {
|
||
let text = suf.as_str();
|
||
if text.is_empty() {
|
||
self.span_bug(sp, "found empty literal suffix in Some")
|
||
}
|
||
let msg = format!("{} with a suffix is invalid", kind);
|
||
self.struct_span_err(sp, &msg)
|
||
.span_label(sp, msg)
|
||
.emit();
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Attempts to consume a `<`. If `<<` is seen, replaces it with a single
|
||
/// `<` and continue. If `<-` is seen, replaces it with a single `<`
|
||
/// and continue. If a `<` is not seen, returns false.
|
||
///
|
||
/// This is meant to be used when parsing generics on a path to get the
|
||
/// starting token.
|
||
fn eat_lt(&mut self) -> bool {
|
||
self.expected_tokens.push(TokenType::Token(token::Lt));
|
||
let ate = match self.token {
|
||
token::Lt => {
|
||
self.bump();
|
||
true
|
||
}
|
||
token::BinOp(token::Shl) => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
self.bump_with(token::Lt, span);
|
||
true
|
||
}
|
||
token::LArrow => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
self.bump_with(token::BinOp(token::Minus), span);
|
||
true
|
||
}
|
||
_ => false,
|
||
};
|
||
|
||
if ate {
|
||
// See doc comment for `unmatched_angle_bracket_count`.
|
||
self.unmatched_angle_bracket_count += 1;
|
||
self.max_angle_bracket_count += 1;
|
||
debug!("eat_lt: (increment) count={:?}", self.unmatched_angle_bracket_count);
|
||
}
|
||
|
||
ate
|
||
}
|
||
|
||
fn expect_lt(&mut self) -> PResult<'a, ()> {
|
||
if !self.eat_lt() {
|
||
self.unexpected()
|
||
} else {
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
/// Expects and consumes a single `>` token. if a `>>` is seen, replaces it
|
||
/// with a single `>` and continues. If a `>` is not seen, signals an error.
|
||
fn expect_gt(&mut self) -> PResult<'a, ()> {
|
||
self.expected_tokens.push(TokenType::Token(token::Gt));
|
||
let ate = match self.token {
|
||
token::Gt => {
|
||
self.bump();
|
||
Some(())
|
||
}
|
||
token::BinOp(token::Shr) => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Some(self.bump_with(token::Gt, span))
|
||
}
|
||
token::BinOpEq(token::Shr) => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Some(self.bump_with(token::Ge, span))
|
||
}
|
||
token::Ge => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Some(self.bump_with(token::Eq, span))
|
||
}
|
||
_ => None,
|
||
};
|
||
|
||
match ate {
|
||
Some(_) => {
|
||
// See doc comment for `unmatched_angle_bracket_count`.
|
||
if self.unmatched_angle_bracket_count > 0 {
|
||
self.unmatched_angle_bracket_count -= 1;
|
||
debug!("expect_gt: (decrement) count={:?}", self.unmatched_angle_bracket_count);
|
||
}
|
||
|
||
Ok(())
|
||
},
|
||
None => self.unexpected(),
|
||
}
|
||
}
|
||
|
||
/// Eats and discards tokens until one of `kets` is encountered. Respects token trees,
|
||
/// passes through any errors encountered. Used for error recovery.
|
||
fn eat_to_tokens(&mut self, kets: &[&token::Token]) {
|
||
let handler = self.diagnostic();
|
||
|
||
if let Err(ref mut err) = self.parse_seq_to_before_tokens(kets,
|
||
SeqSep::none(),
|
||
TokenExpectType::Expect,
|
||
|p| Ok(p.parse_token_tree())) {
|
||
handler.cancel(err);
|
||
}
|
||
}
|
||
|
||
/// Parses a sequence, including the closing delimiter. The function
|
||
/// `f` must consume tokens until reaching the next separator or
|
||
/// closing bracket.
|
||
pub fn parse_seq_to_end<T, F>(&mut self,
|
||
ket: &token::Token,
|
||
sep: SeqSep,
|
||
f: F)
|
||
-> PResult<'a, Vec<T>> where
|
||
F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
|
||
{
|
||
let (val, recovered) = self.parse_seq_to_before_end(ket, sep, f)?;
|
||
if !recovered {
|
||
self.bump();
|
||
}
|
||
Ok(val)
|
||
}
|
||
|
||
/// Parses a sequence, not including the closing delimiter. The function
|
||
/// `f` must consume tokens until reaching the next separator or
|
||
/// closing bracket.
|
||
pub fn parse_seq_to_before_end<T, F>(
|
||
&mut self,
|
||
ket: &token::Token,
|
||
sep: SeqSep,
|
||
f: F,
|
||
) -> PResult<'a, (Vec<T>, bool)>
|
||
where F: FnMut(&mut Parser<'a>) -> PResult<'a, T>
|
||
{
|
||
self.parse_seq_to_before_tokens(&[ket], sep, TokenExpectType::Expect, f)
|
||
}
|
||
|
||
fn parse_seq_to_before_tokens<T, F>(
|
||
&mut self,
|
||
kets: &[&token::Token],
|
||
sep: SeqSep,
|
||
expect: TokenExpectType,
|
||
mut f: F,
|
||
) -> PResult<'a, (Vec<T>, bool /* recovered */)>
|
||
where F: FnMut(&mut Parser<'a>) -> PResult<'a, T>
|
||
{
|
||
let mut first = true;
|
||
let mut recovered = false;
|
||
let mut v = vec![];
|
||
while !kets.iter().any(|k| {
|
||
match expect {
|
||
TokenExpectType::Expect => self.check(k),
|
||
TokenExpectType::NoExpect => self.token == **k,
|
||
}
|
||
}) {
|
||
match self.token {
|
||
token::CloseDelim(..) | token::Eof => break,
|
||
_ => {}
|
||
};
|
||
if let Some(ref t) = sep.sep {
|
||
if first {
|
||
first = false;
|
||
} else {
|
||
match self.expect(t) {
|
||
Ok(false) => {}
|
||
Ok(true) => {
|
||
recovered = true;
|
||
break;
|
||
}
|
||
Err(mut e) => {
|
||
// Attempt to keep parsing if it was a similar separator
|
||
if let Some(ref tokens) = t.similar_tokens() {
|
||
if tokens.contains(&self.token) {
|
||
self.bump();
|
||
}
|
||
}
|
||
e.emit();
|
||
// Attempt to keep parsing if it was an omitted separator
|
||
match f(self) {
|
||
Ok(t) => {
|
||
v.push(t);
|
||
continue;
|
||
},
|
||
Err(mut e) => {
|
||
e.cancel();
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
if sep.trailing_sep_allowed && kets.iter().any(|k| {
|
||
match expect {
|
||
TokenExpectType::Expect => self.check(k),
|
||
TokenExpectType::NoExpect => self.token == **k,
|
||
}
|
||
}) {
|
||
break;
|
||
}
|
||
|
||
let t = f(self)?;
|
||
v.push(t);
|
||
}
|
||
|
||
Ok((v, recovered))
|
||
}
|
||
|
||
/// Parses a sequence, including the closing delimiter. The function
|
||
/// `f` must consume tokens until reaching the next separator or
|
||
/// closing bracket.
|
||
fn parse_unspanned_seq<T, F>(
|
||
&mut self,
|
||
bra: &token::Token,
|
||
ket: &token::Token,
|
||
sep: SeqSep,
|
||
f: F,
|
||
) -> PResult<'a, Vec<T>> where
|
||
F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
|
||
{
|
||
self.expect(bra)?;
|
||
let (result, recovered) = self.parse_seq_to_before_end(ket, sep, f)?;
|
||
if !recovered {
|
||
self.eat(ket);
|
||
}
|
||
Ok(result)
|
||
}
|
||
|
||
/// Advance the parser by one token
|
||
pub fn bump(&mut self) {
|
||
if self.prev_token_kind == PrevTokenKind::Eof {
|
||
// Bumping after EOF is a bad sign, usually an infinite loop.
|
||
self.bug("attempted to bump the parser past EOF (may be stuck in a loop)");
|
||
}
|
||
|
||
self.prev_span = self.meta_var_span.take().unwrap_or(self.span);
|
||
|
||
// Record last token kind for possible error recovery.
|
||
self.prev_token_kind = match self.token {
|
||
token::DocComment(..) => PrevTokenKind::DocComment,
|
||
token::Comma => PrevTokenKind::Comma,
|
||
token::BinOp(token::Plus) => PrevTokenKind::Plus,
|
||
token::Interpolated(..) => PrevTokenKind::Interpolated,
|
||
token::Eof => PrevTokenKind::Eof,
|
||
token::Ident(..) => PrevTokenKind::Ident,
|
||
_ => PrevTokenKind::Other,
|
||
};
|
||
|
||
let next = self.next_tok();
|
||
self.span = next.sp;
|
||
self.token = next.tok;
|
||
self.expected_tokens.clear();
|
||
// check after each token
|
||
self.process_potential_macro_variable();
|
||
}
|
||
|
||
/// Advance the parser using provided token as a next one. Use this when
|
||
/// consuming a part of a token. For example a single `<` from `<<`.
|
||
fn bump_with(&mut self, next: token::Token, span: Span) {
|
||
self.prev_span = self.span.with_hi(span.lo());
|
||
// It would be incorrect to record the kind of the current token, but
|
||
// fortunately for tokens currently using `bump_with`, the
|
||
// prev_token_kind will be of no use anyway.
|
||
self.prev_token_kind = PrevTokenKind::Other;
|
||
self.span = span;
|
||
self.token = next;
|
||
self.expected_tokens.clear();
|
||
}
|
||
|
||
pub fn look_ahead<R, F>(&self, dist: usize, f: F) -> R where
|
||
F: FnOnce(&token::Token) -> R,
|
||
{
|
||
if dist == 0 {
|
||
return f(&self.token)
|
||
}
|
||
|
||
f(&match self.token_cursor.frame.tree_cursor.look_ahead(dist - 1) {
|
||
Some(tree) => match tree {
|
||
TokenTree::Token(_, tok) => tok,
|
||
TokenTree::Delimited(_, delim, _) => token::OpenDelim(delim),
|
||
},
|
||
None => token::CloseDelim(self.token_cursor.frame.delim),
|
||
})
|
||
}
|
||
|
||
fn look_ahead_span(&self, dist: usize) -> Span {
|
||
if dist == 0 {
|
||
return self.span
|
||
}
|
||
|
||
match self.token_cursor.frame.tree_cursor.look_ahead(dist - 1) {
|
||
Some(TokenTree::Token(span, _)) => span,
|
||
Some(TokenTree::Delimited(span, ..)) => span.entire(),
|
||
None => self.look_ahead_span(dist - 1),
|
||
}
|
||
}
|
||
pub fn fatal(&self, m: &str) -> DiagnosticBuilder<'a> {
|
||
self.sess.span_diagnostic.struct_span_fatal(self.span, m)
|
||
}
|
||
pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> DiagnosticBuilder<'a> {
|
||
self.sess.span_diagnostic.struct_span_fatal(sp, m)
|
||
}
|
||
fn span_fatal_err<S: Into<MultiSpan>>(&self, sp: S, err: Error) -> DiagnosticBuilder<'a> {
|
||
err.span_err(sp, self.diagnostic())
|
||
}
|
||
fn bug(&self, m: &str) -> ! {
|
||
self.sess.span_diagnostic.span_bug(self.span, m)
|
||
}
|
||
fn span_err<S: Into<MultiSpan>>(&self, sp: S, m: &str) {
|
||
self.sess.span_diagnostic.span_err(sp, m)
|
||
}
|
||
fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> DiagnosticBuilder<'a> {
|
||
self.sess.span_diagnostic.struct_span_err(sp, m)
|
||
}
|
||
crate fn span_bug<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> ! {
|
||
self.sess.span_diagnostic.span_bug(sp, m)
|
||
}
|
||
|
||
fn cancel(&self, err: &mut DiagnosticBuilder<'_>) {
|
||
self.sess.span_diagnostic.cancel(err)
|
||
}
|
||
|
||
crate fn diagnostic(&self) -> &'a errors::Handler {
|
||
&self.sess.span_diagnostic
|
||
}
|
||
|
||
/// Is the current token one of the keywords that signals a bare function type?
|
||
fn token_is_bare_fn_keyword(&mut self) -> bool {
|
||
self.check_keyword(keywords::Fn) ||
|
||
self.check_keyword(keywords::Unsafe) ||
|
||
self.check_keyword(keywords::Extern)
|
||
}
|
||
|
||
/// Parses a `TyKind::BareFn` type.
|
||
fn parse_ty_bare_fn(&mut self, generic_params: Vec<GenericParam>) -> PResult<'a, TyKind> {
|
||
/*
|
||
|
||
[unsafe] [extern "ABI"] fn (S) -> T
|
||
^~~~^ ^~~~^ ^~^ ^
|
||
| | | |
|
||
| | | Return type
|
||
| | Argument types
|
||
| |
|
||
| ABI
|
||
Function Style
|
||
*/
|
||
|
||
let unsafety = self.parse_unsafety();
|
||
let abi = if self.eat_keyword(keywords::Extern) {
|
||
self.parse_opt_abi()?.unwrap_or(Abi::C)
|
||
} else {
|
||
Abi::Rust
|
||
};
|
||
|
||
self.expect_keyword(keywords::Fn)?;
|
||
let (inputs, variadic) = self.parse_fn_args(false, true)?;
|
||
let ret_ty = self.parse_ret_ty(false)?;
|
||
let decl = P(FnDecl {
|
||
inputs,
|
||
output: ret_ty,
|
||
variadic,
|
||
});
|
||
Ok(TyKind::BareFn(P(BareFnTy {
|
||
abi,
|
||
unsafety,
|
||
generic_params,
|
||
decl,
|
||
})))
|
||
}
|
||
|
||
/// Parses asyncness: `async` or nothing.
|
||
fn parse_asyncness(&mut self) -> IsAsync {
|
||
if self.eat_keyword(keywords::Async) {
|
||
IsAsync::Async {
|
||
closure_id: ast::DUMMY_NODE_ID,
|
||
return_impl_trait_id: ast::DUMMY_NODE_ID,
|
||
}
|
||
} else {
|
||
IsAsync::NotAsync
|
||
}
|
||
}
|
||
|
||
/// Parses unsafety: `unsafe` or nothing.
|
||
fn parse_unsafety(&mut self) -> Unsafety {
|
||
if self.eat_keyword(keywords::Unsafe) {
|
||
Unsafety::Unsafe
|
||
} else {
|
||
Unsafety::Normal
|
||
}
|
||
}
|
||
|
||
/// Parses the items in a trait declaration.
|
||
pub fn parse_trait_item(&mut self, at_end: &mut bool) -> PResult<'a, TraitItem> {
|
||
maybe_whole!(self, NtTraitItem, |x| x);
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let (mut item, tokens) = self.collect_tokens(|this| {
|
||
this.parse_trait_item_(at_end, attrs)
|
||
})?;
|
||
// See `parse_item` for why this clause is here.
|
||
if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
|
||
item.tokens = Some(tokens);
|
||
}
|
||
Ok(item)
|
||
}
|
||
|
||
fn parse_trait_item_(&mut self,
|
||
at_end: &mut bool,
|
||
mut attrs: Vec<Attribute>) -> PResult<'a, TraitItem> {
|
||
let lo = self.span;
|
||
|
||
let (name, node, generics) = if self.eat_keyword(keywords::Type) {
|
||
self.parse_trait_item_assoc_ty()?
|
||
} else if self.is_const_item() {
|
||
self.expect_keyword(keywords::Const)?;
|
||
let ident = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
let default = if self.eat(&token::Eq) {
|
||
let expr = self.parse_expr()?;
|
||
self.expect(&token::Semi)?;
|
||
Some(expr)
|
||
} else {
|
||
self.expect(&token::Semi)?;
|
||
None
|
||
};
|
||
(ident, TraitItemKind::Const(ty, default), ast::Generics::default())
|
||
} else if let Some(mac) = self.parse_assoc_macro_invoc("trait", None, &mut false)? {
|
||
// trait item macro.
|
||
(keywords::Invalid.ident(), ast::TraitItemKind::Macro(mac), ast::Generics::default())
|
||
} else {
|
||
let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?;
|
||
|
||
let ident = self.parse_ident()?;
|
||
let mut generics = self.parse_generics()?;
|
||
|
||
let d = self.parse_fn_decl_with_self(|p: &mut Parser<'a>| {
|
||
// This is somewhat dubious; We don't want to allow
|
||
// argument names to be left off if there is a
|
||
// definition...
|
||
|
||
// We don't allow argument names to be left off in edition 2018.
|
||
p.parse_arg_general(p.span.rust_2018(), true)
|
||
})?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
|
||
let sig = ast::MethodSig {
|
||
header: FnHeader {
|
||
unsafety,
|
||
constness,
|
||
abi,
|
||
asyncness,
|
||
},
|
||
decl: d,
|
||
};
|
||
|
||
let body = match self.token {
|
||
token::Semi => {
|
||
self.bump();
|
||
*at_end = true;
|
||
debug!("parse_trait_methods(): parsing required method");
|
||
None
|
||
}
|
||
token::OpenDelim(token::Brace) => {
|
||
debug!("parse_trait_methods(): parsing provided method");
|
||
*at_end = true;
|
||
let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(inner_attrs.iter().cloned());
|
||
Some(body)
|
||
}
|
||
token::Interpolated(ref nt) => {
|
||
match **nt {
|
||
token::NtBlock(..) => {
|
||
*at_end = true;
|
||
let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(inner_attrs.iter().cloned());
|
||
Some(body)
|
||
}
|
||
_ => {
|
||
let token_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!("expected `;` or `{{`, found {}",
|
||
token_str));
|
||
err.span_label(self.span, "expected `;` or `{`");
|
||
return Err(err);
|
||
}
|
||
}
|
||
}
|
||
_ => {
|
||
let token_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!("expected `;` or `{{`, found {}",
|
||
token_str));
|
||
err.span_label(self.span, "expected `;` or `{`");
|
||
return Err(err);
|
||
}
|
||
};
|
||
(ident, ast::TraitItemKind::Method(sig, body), generics)
|
||
};
|
||
|
||
Ok(TraitItem {
|
||
id: ast::DUMMY_NODE_ID,
|
||
ident: name,
|
||
attrs,
|
||
generics,
|
||
node,
|
||
span: lo.to(self.prev_span),
|
||
tokens: None,
|
||
})
|
||
}
|
||
|
||
/// Parses an optional return type `[ -> TY ]` in a function declaration.
|
||
fn parse_ret_ty(&mut self, allow_plus: bool) -> PResult<'a, FunctionRetTy> {
|
||
if self.eat(&token::RArrow) {
|
||
Ok(FunctionRetTy::Ty(self.parse_ty_common(allow_plus, true)?))
|
||
} else {
|
||
Ok(FunctionRetTy::Default(self.span.shrink_to_lo()))
|
||
}
|
||
}
|
||
|
||
/// Parses a type.
|
||
pub fn parse_ty(&mut self) -> PResult<'a, P<Ty>> {
|
||
self.parse_ty_common(true, true)
|
||
}
|
||
|
||
/// Parses a type in restricted contexts where `+` is not permitted.
|
||
///
|
||
/// Example 1: `&'a TYPE`
|
||
/// `+` is prohibited to maintain operator priority (P(+) < P(&)).
|
||
/// Example 2: `value1 as TYPE + value2`
|
||
/// `+` is prohibited to avoid interactions with expression grammar.
|
||
fn parse_ty_no_plus(&mut self) -> PResult<'a, P<Ty>> {
|
||
self.parse_ty_common(false, true)
|
||
}
|
||
|
||
fn parse_ty_common(&mut self, allow_plus: bool, allow_qpath_recovery: bool)
|
||
-> PResult<'a, P<Ty>> {
|
||
maybe_whole!(self, NtTy, |x| x);
|
||
|
||
let lo = self.span;
|
||
let mut impl_dyn_multi = false;
|
||
let node = if self.eat(&token::OpenDelim(token::Paren)) {
|
||
// `(TYPE)` is a parenthesized type.
|
||
// `(TYPE,)` is a tuple with a single field of type TYPE.
|
||
let mut ts = vec![];
|
||
let mut last_comma = false;
|
||
while self.token != token::CloseDelim(token::Paren) {
|
||
ts.push(self.parse_ty()?);
|
||
if self.eat(&token::Comma) {
|
||
last_comma = true;
|
||
} else {
|
||
last_comma = false;
|
||
break;
|
||
}
|
||
}
|
||
let trailing_plus = self.prev_token_kind == PrevTokenKind::Plus;
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
|
||
if ts.len() == 1 && !last_comma {
|
||
let ty = ts.into_iter().nth(0).unwrap().into_inner();
|
||
let maybe_bounds = allow_plus && self.token.is_like_plus();
|
||
match ty.node {
|
||
// `(TY_BOUND_NOPAREN) + BOUND + ...`.
|
||
TyKind::Path(None, ref path) if maybe_bounds => {
|
||
self.parse_remaining_bounds(Vec::new(), path.clone(), lo, true)?
|
||
}
|
||
TyKind::TraitObject(ref bounds, TraitObjectSyntax::None)
|
||
if maybe_bounds && bounds.len() == 1 && !trailing_plus => {
|
||
let path = match bounds[0] {
|
||
GenericBound::Trait(ref pt, ..) => pt.trait_ref.path.clone(),
|
||
GenericBound::Outlives(..) => self.bug("unexpected lifetime bound"),
|
||
};
|
||
self.parse_remaining_bounds(Vec::new(), path, lo, true)?
|
||
}
|
||
// `(TYPE)`
|
||
_ => TyKind::Paren(P(ty))
|
||
}
|
||
} else {
|
||
TyKind::Tup(ts)
|
||
}
|
||
} else if self.eat(&token::Not) {
|
||
// Never type `!`
|
||
TyKind::Never
|
||
} else if self.eat(&token::BinOp(token::Star)) {
|
||
// Raw pointer
|
||
TyKind::Ptr(self.parse_ptr()?)
|
||
} else if self.eat(&token::OpenDelim(token::Bracket)) {
|
||
// Array or slice
|
||
let t = self.parse_ty()?;
|
||
// Parse optional `; EXPR` in `[TYPE; EXPR]`
|
||
let t = match self.maybe_parse_fixed_length_of_vec()? {
|
||
None => TyKind::Slice(t),
|
||
Some(length) => TyKind::Array(t, AnonConst {
|
||
id: ast::DUMMY_NODE_ID,
|
||
value: length,
|
||
}),
|
||
};
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
t
|
||
} else if self.check(&token::BinOp(token::And)) || self.check(&token::AndAnd) {
|
||
// Reference
|
||
self.expect_and()?;
|
||
self.parse_borrowed_pointee()?
|
||
} else if self.eat_keyword_noexpect(keywords::Typeof) {
|
||
// `typeof(EXPR)`
|
||
// In order to not be ambiguous, the type must be surrounded by parens.
|
||
self.expect(&token::OpenDelim(token::Paren))?;
|
||
let e = AnonConst {
|
||
id: ast::DUMMY_NODE_ID,
|
||
value: self.parse_expr()?,
|
||
};
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
TyKind::Typeof(e)
|
||
} else if self.eat_keyword(keywords::Underscore) {
|
||
// A type to be inferred `_`
|
||
TyKind::Infer
|
||
} else if self.token_is_bare_fn_keyword() {
|
||
// Function pointer type
|
||
self.parse_ty_bare_fn(Vec::new())?
|
||
} else if self.check_keyword(keywords::For) {
|
||
// Function pointer type or bound list (trait object type) starting with a poly-trait.
|
||
// `for<'lt> [unsafe] [extern "ABI"] fn (&'lt S) -> T`
|
||
// `for<'lt> Trait1<'lt> + Trait2 + 'a`
|
||
let lo = self.span;
|
||
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
||
if self.token_is_bare_fn_keyword() {
|
||
self.parse_ty_bare_fn(lifetime_defs)?
|
||
} else {
|
||
let path = self.parse_path(PathStyle::Type)?;
|
||
let parse_plus = allow_plus && self.check_plus();
|
||
self.parse_remaining_bounds(lifetime_defs, path, lo, parse_plus)?
|
||
}
|
||
} else if self.eat_keyword(keywords::Impl) {
|
||
// Always parse bounds greedily for better error recovery.
|
||
let bounds = self.parse_generic_bounds(None)?;
|
||
impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
|
||
TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds)
|
||
} else if self.check_keyword(keywords::Dyn) &&
|
||
(self.span.rust_2018() ||
|
||
self.look_ahead(1, |t| t.can_begin_bound() &&
|
||
!can_continue_type_after_non_fn_ident(t))) {
|
||
self.bump(); // `dyn`
|
||
// Always parse bounds greedily for better error recovery.
|
||
let bounds = self.parse_generic_bounds(None)?;
|
||
impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
|
||
TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn)
|
||
} else if self.check(&token::Question) ||
|
||
self.check_lifetime() && self.look_ahead(1, |t| t.is_like_plus()) {
|
||
// Bound list (trait object type)
|
||
TyKind::TraitObject(self.parse_generic_bounds_common(allow_plus, None)?,
|
||
TraitObjectSyntax::None)
|
||
} else if self.eat_lt() {
|
||
// Qualified path
|
||
let (qself, path) = self.parse_qpath(PathStyle::Type)?;
|
||
TyKind::Path(Some(qself), path)
|
||
} else if self.token.is_path_start() {
|
||
// Simple path
|
||
let path = self.parse_path(PathStyle::Type)?;
|
||
if self.eat(&token::Not) {
|
||
// Macro invocation in type position
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
let node = Mac_ { path, tts, delim };
|
||
TyKind::Mac(respan(lo.to(self.prev_span), node))
|
||
} else {
|
||
// Just a type path or bound list (trait object type) starting with a trait.
|
||
// `Type`
|
||
// `Trait1 + Trait2 + 'a`
|
||
if allow_plus && self.check_plus() {
|
||
self.parse_remaining_bounds(Vec::new(), path, lo, true)?
|
||
} else {
|
||
TyKind::Path(None, path)
|
||
}
|
||
}
|
||
} else {
|
||
let msg = format!("expected type, found {}", self.this_token_descr());
|
||
return Err(self.fatal(&msg));
|
||
};
|
||
|
||
let span = lo.to(self.prev_span);
|
||
let ty = Ty { node, span, id: ast::DUMMY_NODE_ID };
|
||
|
||
// Try to recover from use of `+` with incorrect priority.
|
||
self.maybe_report_ambiguous_plus(allow_plus, impl_dyn_multi, &ty);
|
||
self.maybe_recover_from_bad_type_plus(allow_plus, &ty)?;
|
||
let ty = self.maybe_recover_from_bad_qpath(ty, allow_qpath_recovery)?;
|
||
|
||
Ok(P(ty))
|
||
}
|
||
|
||
fn parse_remaining_bounds(&mut self, generic_params: Vec<GenericParam>, path: ast::Path,
|
||
lo: Span, parse_plus: bool) -> PResult<'a, TyKind> {
|
||
let poly_trait_ref = PolyTraitRef::new(generic_params, path, lo.to(self.prev_span));
|
||
let mut bounds = vec![GenericBound::Trait(poly_trait_ref, TraitBoundModifier::None)];
|
||
if parse_plus {
|
||
self.eat_plus(); // `+`, or `+=` gets split and `+` is discarded
|
||
bounds.append(&mut self.parse_generic_bounds(None)?);
|
||
}
|
||
Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::None))
|
||
}
|
||
|
||
fn maybe_report_ambiguous_plus(&mut self, allow_plus: bool, impl_dyn_multi: bool, ty: &Ty) {
|
||
if !allow_plus && impl_dyn_multi {
|
||
let sum_with_parens = format!("({})", pprust::ty_to_string(&ty));
|
||
self.struct_span_err(ty.span, "ambiguous `+` in a type")
|
||
.span_suggestion(
|
||
ty.span,
|
||
"use parentheses to disambiguate",
|
||
sum_with_parens,
|
||
Applicability::MachineApplicable
|
||
).emit();
|
||
}
|
||
}
|
||
|
||
fn maybe_recover_from_bad_type_plus(&mut self, allow_plus: bool, ty: &Ty) -> PResult<'a, ()> {
|
||
// Do not add `+` to expected tokens.
|
||
if !allow_plus || !self.token.is_like_plus() {
|
||
return Ok(())
|
||
}
|
||
|
||
self.bump(); // `+`
|
||
let bounds = self.parse_generic_bounds(None)?;
|
||
let sum_span = ty.span.to(self.prev_span);
|
||
|
||
let mut err = struct_span_err!(self.sess.span_diagnostic, sum_span, E0178,
|
||
"expected a path on the left-hand side of `+`, not `{}`", pprust::ty_to_string(ty));
|
||
|
||
match ty.node {
|
||
TyKind::Rptr(ref lifetime, ref mut_ty) => {
|
||
let sum_with_parens = pprust::to_string(|s| {
|
||
use crate::print::pprust::PrintState;
|
||
|
||
s.s.word("&")?;
|
||
s.print_opt_lifetime(lifetime)?;
|
||
s.print_mutability(mut_ty.mutbl)?;
|
||
s.popen()?;
|
||
s.print_type(&mut_ty.ty)?;
|
||
s.print_type_bounds(" +", &bounds)?;
|
||
s.pclose()
|
||
});
|
||
err.span_suggestion(
|
||
sum_span,
|
||
"try adding parentheses",
|
||
sum_with_parens,
|
||
Applicability::MachineApplicable
|
||
);
|
||
}
|
||
TyKind::Ptr(..) | TyKind::BareFn(..) => {
|
||
err.span_label(sum_span, "perhaps you forgot parentheses?");
|
||
}
|
||
_ => {
|
||
err.span_label(sum_span, "expected a path");
|
||
},
|
||
}
|
||
err.emit();
|
||
Ok(())
|
||
}
|
||
|
||
// Try to recover from associated item paths like `[T]::AssocItem`/`(T, U)::AssocItem`.
|
||
fn maybe_recover_from_bad_qpath<T: RecoverQPath>(&mut self, base: T, allow_recovery: bool)
|
||
-> PResult<'a, T> {
|
||
// Do not add `::` to expected tokens.
|
||
if !allow_recovery || self.token != token::ModSep {
|
||
return Ok(base);
|
||
}
|
||
let ty = match base.to_ty() {
|
||
Some(ty) => ty,
|
||
None => return Ok(base),
|
||
};
|
||
|
||
self.bump(); // `::`
|
||
let mut segments = Vec::new();
|
||
self.parse_path_segments(&mut segments, T::PATH_STYLE, true)?;
|
||
|
||
let span = ty.span.to(self.prev_span);
|
||
let path_span = span.to(span); // use an empty path since `position` == 0
|
||
let recovered = base.to_recovered(
|
||
Some(QSelf { ty, path_span, position: 0 }),
|
||
ast::Path { segments, span },
|
||
);
|
||
|
||
self.diagnostic()
|
||
.struct_span_err(span, "missing angle brackets in associated item path")
|
||
.span_suggestion( // this is a best-effort recovery
|
||
span, "try", recovered.to_string(), Applicability::MaybeIncorrect
|
||
).emit();
|
||
|
||
Ok(recovered)
|
||
}
|
||
|
||
fn parse_borrowed_pointee(&mut self) -> PResult<'a, TyKind> {
|
||
let opt_lifetime = if self.check_lifetime() { Some(self.expect_lifetime()) } else { None };
|
||
let mutbl = self.parse_mutability();
|
||
let ty = self.parse_ty_no_plus()?;
|
||
return Ok(TyKind::Rptr(opt_lifetime, MutTy { ty: ty, mutbl: mutbl }));
|
||
}
|
||
|
||
fn parse_ptr(&mut self) -> PResult<'a, MutTy> {
|
||
let mutbl = if self.eat_keyword(keywords::Mut) {
|
||
Mutability::Mutable
|
||
} else if self.eat_keyword(keywords::Const) {
|
||
Mutability::Immutable
|
||
} else {
|
||
let span = self.prev_span;
|
||
let msg = "expected mut or const in raw pointer type";
|
||
self.struct_span_err(span, msg)
|
||
.span_label(span, msg)
|
||
.help("use `*mut T` or `*const T` as appropriate")
|
||
.emit();
|
||
Mutability::Immutable
|
||
};
|
||
let t = self.parse_ty_no_plus()?;
|
||
Ok(MutTy { ty: t, mutbl: mutbl })
|
||
}
|
||
|
||
fn is_named_argument(&mut self) -> bool {
|
||
let offset = match self.token {
|
||
token::Interpolated(ref nt) => match **nt {
|
||
token::NtPat(..) => return self.look_ahead(1, |t| t == &token::Colon),
|
||
_ => 0,
|
||
}
|
||
token::BinOp(token::And) | token::AndAnd => 1,
|
||
_ if self.token.is_keyword(keywords::Mut) => 1,
|
||
_ => 0,
|
||
};
|
||
|
||
self.look_ahead(offset, |t| t.is_ident()) &&
|
||
self.look_ahead(offset + 1, |t| t == &token::Colon)
|
||
}
|
||
|
||
/// Skips unexpected attributes and doc comments in this position and emits an appropriate
|
||
/// error.
|
||
fn eat_incorrect_doc_comment(&mut self, applied_to: &str) {
|
||
if let token::DocComment(_) = self.token {
|
||
let mut err = self.diagnostic().struct_span_err(
|
||
self.span,
|
||
&format!("documentation comments cannot be applied to {}", applied_to),
|
||
);
|
||
err.span_label(self.span, "doc comments are not allowed here");
|
||
err.emit();
|
||
self.bump();
|
||
} else if self.token == token::Pound && self.look_ahead(1, |t| {
|
||
*t == token::OpenDelim(token::Bracket)
|
||
}) {
|
||
let lo = self.span;
|
||
// Skip every token until next possible arg.
|
||
while self.token != token::CloseDelim(token::Bracket) {
|
||
self.bump();
|
||
}
|
||
let sp = lo.to(self.span);
|
||
self.bump();
|
||
let mut err = self.diagnostic().struct_span_err(
|
||
sp,
|
||
&format!("attributes cannot be applied to {}", applied_to),
|
||
);
|
||
err.span_label(sp, "attributes are not allowed here");
|
||
err.emit();
|
||
}
|
||
}
|
||
|
||
/// This version of parse arg doesn't necessarily require identifier names.
|
||
fn parse_arg_general(&mut self, require_name: bool, is_trait_item: bool) -> PResult<'a, Arg> {
|
||
maybe_whole!(self, NtArg, |x| x);
|
||
|
||
if let Ok(Some(_)) = self.parse_self_arg() {
|
||
let mut err = self.struct_span_err(self.prev_span,
|
||
"unexpected `self` argument in function");
|
||
err.span_label(self.prev_span,
|
||
"`self` is only valid as the first argument of an associated function");
|
||
return Err(err);
|
||
}
|
||
|
||
let (pat, ty) = if require_name || self.is_named_argument() {
|
||
debug!("parse_arg_general parse_pat (require_name:{})",
|
||
require_name);
|
||
self.eat_incorrect_doc_comment("method arguments");
|
||
let pat = self.parse_pat(Some("argument name"))?;
|
||
|
||
if let Err(mut err) = self.expect(&token::Colon) {
|
||
// If we find a pattern followed by an identifier, it could be an (incorrect)
|
||
// C-style parameter declaration.
|
||
if self.check_ident() && self.look_ahead(1, |t| {
|
||
*t == token::Comma || *t == token::CloseDelim(token::Paren)
|
||
}) {
|
||
let ident = self.parse_ident().unwrap();
|
||
let span = pat.span.with_hi(ident.span.hi());
|
||
|
||
err.span_suggestion(
|
||
span,
|
||
"declare the type after the parameter binding",
|
||
"<identifier>: <type>",
|
||
Applicability::HasPlaceholders,
|
||
);
|
||
} else if require_name && is_trait_item {
|
||
if let PatKind::Ident(_, ident, _) = pat.node {
|
||
err.span_suggestion(
|
||
pat.span,
|
||
"explicitly ignore parameter",
|
||
format!("_: {}", ident),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
}
|
||
|
||
err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)");
|
||
}
|
||
|
||
return Err(err);
|
||
}
|
||
|
||
self.eat_incorrect_doc_comment("a method argument's type");
|
||
(pat, self.parse_ty()?)
|
||
} else {
|
||
debug!("parse_arg_general ident_to_pat");
|
||
let parser_snapshot_before_ty = self.clone();
|
||
self.eat_incorrect_doc_comment("a method argument's type");
|
||
let mut ty = self.parse_ty();
|
||
if ty.is_ok() && self.token != token::Comma &&
|
||
self.token != token::CloseDelim(token::Paren) {
|
||
// This wasn't actually a type, but a pattern looking like a type,
|
||
// so we are going to rollback and re-parse for recovery.
|
||
ty = self.unexpected();
|
||
}
|
||
match ty {
|
||
Ok(ty) => {
|
||
let ident = Ident::new(keywords::Invalid.name(), self.prev_span);
|
||
let pat = P(Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Ident(
|
||
BindingMode::ByValue(Mutability::Immutable), ident, None),
|
||
span: ty.span,
|
||
});
|
||
(pat, ty)
|
||
}
|
||
Err(mut err) => {
|
||
// Recover from attempting to parse the argument as a type without pattern.
|
||
err.cancel();
|
||
mem::replace(self, parser_snapshot_before_ty);
|
||
let pat = self.parse_pat(Some("argument name"))?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
|
||
let mut err = self.diagnostic().struct_span_err_with_code(
|
||
pat.span,
|
||
"patterns aren't allowed in methods without bodies",
|
||
DiagnosticId::Error("E0642".into()),
|
||
);
|
||
err.span_suggestion_short(
|
||
pat.span,
|
||
"give this argument a name or use an underscore to ignore it",
|
||
"_".to_owned(),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
err.emit();
|
||
|
||
// Pretend the pattern is `_`, to avoid duplicate errors from AST validation.
|
||
let pat = P(Pat {
|
||
node: PatKind::Wild,
|
||
span: pat.span,
|
||
id: ast::DUMMY_NODE_ID
|
||
});
|
||
(pat, ty)
|
||
}
|
||
}
|
||
};
|
||
|
||
Ok(Arg { ty, pat, id: ast::DUMMY_NODE_ID })
|
||
}
|
||
|
||
/// Parses a single function argument.
|
||
crate fn parse_arg(&mut self) -> PResult<'a, Arg> {
|
||
self.parse_arg_general(true, false)
|
||
}
|
||
|
||
/// Parses an argument in a lambda header (e.g., `|arg, arg|`).
|
||
fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> {
|
||
let pat = self.parse_pat(Some("argument name"))?;
|
||
let t = if self.eat(&token::Colon) {
|
||
self.parse_ty()?
|
||
} else {
|
||
P(Ty {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: TyKind::Infer,
|
||
span: self.prev_span,
|
||
})
|
||
};
|
||
Ok(Arg {
|
||
ty: t,
|
||
pat,
|
||
id: ast::DUMMY_NODE_ID
|
||
})
|
||
}
|
||
|
||
fn maybe_parse_fixed_length_of_vec(&mut self) -> PResult<'a, Option<P<ast::Expr>>> {
|
||
if self.eat(&token::Semi) {
|
||
Ok(Some(self.parse_expr()?))
|
||
} else {
|
||
Ok(None)
|
||
}
|
||
}
|
||
|
||
/// Matches `token_lit = LIT_INTEGER | ...`.
|
||
fn parse_lit_token(&mut self) -> PResult<'a, LitKind> {
|
||
let out = match self.token {
|
||
token::Interpolated(ref nt) => match **nt {
|
||
token::NtExpr(ref v) | token::NtLiteral(ref v) => match v.node {
|
||
ExprKind::Lit(ref lit) => { lit.node.clone() }
|
||
_ => { return self.unexpected_last(&self.token); }
|
||
},
|
||
_ => { return self.unexpected_last(&self.token); }
|
||
},
|
||
token::Literal(lit, suf) => {
|
||
let diag = Some((self.span, &self.sess.span_diagnostic));
|
||
let (suffix_illegal, result) = parse::lit_token(lit, suf, diag);
|
||
|
||
if suffix_illegal {
|
||
let sp = self.span;
|
||
self.expect_no_suffix(sp, lit.literal_name(), suf)
|
||
}
|
||
|
||
result.unwrap()
|
||
}
|
||
token::Dot if self.look_ahead(1, |t| match t {
|
||
token::Literal(parse::token::Lit::Integer(_) , _) => true,
|
||
_ => false,
|
||
}) => { // recover from `let x = .4;`
|
||
let lo = self.span;
|
||
self.bump();
|
||
if let token::Literal(
|
||
parse::token::Lit::Integer(val),
|
||
suffix,
|
||
) = self.token {
|
||
let suffix = suffix.and_then(|s| {
|
||
let s = s.as_str().get();
|
||
if ["f32", "f64"].contains(&s) {
|
||
Some(s)
|
||
} else {
|
||
None
|
||
}
|
||
}).unwrap_or("");
|
||
self.bump();
|
||
let sp = lo.to(self.prev_span);
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "float literals must have an integer part");
|
||
err.span_suggestion(
|
||
sp,
|
||
"must have an integer part",
|
||
format!("0.{}{}", val, suffix),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
err.emit();
|
||
return Ok(match suffix {
|
||
"f32" => ast::LitKind::Float(val, ast::FloatTy::F32),
|
||
"f64" => ast::LitKind::Float(val, ast::FloatTy::F64),
|
||
_ => ast::LitKind::FloatUnsuffixed(val),
|
||
});
|
||
} else {
|
||
unreachable!();
|
||
};
|
||
}
|
||
_ => { return self.unexpected_last(&self.token); }
|
||
};
|
||
|
||
self.bump();
|
||
Ok(out)
|
||
}
|
||
|
||
/// Matches `lit = true | false | token_lit`.
|
||
crate fn parse_lit(&mut self) -> PResult<'a, Lit> {
|
||
let lo = self.span;
|
||
let lit = if self.eat_keyword(keywords::True) {
|
||
LitKind::Bool(true)
|
||
} else if self.eat_keyword(keywords::False) {
|
||
LitKind::Bool(false)
|
||
} else {
|
||
let lit = self.parse_lit_token()?;
|
||
lit
|
||
};
|
||
Ok(source_map::Spanned { node: lit, span: lo.to(self.prev_span) })
|
||
}
|
||
|
||
/// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).
|
||
crate fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
|
||
maybe_whole_expr!(self);
|
||
|
||
let minus_lo = self.span;
|
||
let minus_present = self.eat(&token::BinOp(token::Minus));
|
||
let lo = self.span;
|
||
let literal = self.parse_lit()?;
|
||
let hi = self.prev_span;
|
||
let expr = self.mk_expr(lo.to(hi), ExprKind::Lit(literal), ThinVec::new());
|
||
|
||
if minus_present {
|
||
let minus_hi = self.prev_span;
|
||
let unary = self.mk_unary(UnOp::Neg, expr);
|
||
Ok(self.mk_expr(minus_lo.to(minus_hi), unary, ThinVec::new()))
|
||
} else {
|
||
Ok(expr)
|
||
}
|
||
}
|
||
|
||
fn parse_path_segment_ident(&mut self) -> PResult<'a, ast::Ident> {
|
||
match self.token {
|
||
token::Ident(ident, _) if self.token.is_path_segment_keyword() => {
|
||
let span = self.span;
|
||
self.bump();
|
||
Ok(Ident::new(ident.name, span))
|
||
}
|
||
_ => self.parse_ident(),
|
||
}
|
||
}
|
||
|
||
fn parse_ident_or_underscore(&mut self) -> PResult<'a, ast::Ident> {
|
||
match self.token {
|
||
token::Ident(ident, false) if ident.name == keywords::Underscore.name() => {
|
||
let span = self.span;
|
||
self.bump();
|
||
Ok(Ident::new(ident.name, span))
|
||
}
|
||
_ => self.parse_ident(),
|
||
}
|
||
}
|
||
|
||
/// Parses a qualified path.
|
||
/// Assumes that the leading `<` has been parsed already.
|
||
///
|
||
/// `qualified_path = <type [as trait_ref]>::path`
|
||
///
|
||
/// # Examples
|
||
/// `<T>::default`
|
||
/// `<T as U>::a`
|
||
/// `<T as U>::F::a<S>` (without disambiguator)
|
||
/// `<T as U>::F::a::<S>` (with disambiguator)
|
||
fn parse_qpath(&mut self, style: PathStyle) -> PResult<'a, (QSelf, ast::Path)> {
|
||
let lo = self.prev_span;
|
||
let ty = self.parse_ty()?;
|
||
|
||
// `path` will contain the prefix of the path up to the `>`,
|
||
// if any (e.g., `U` in the `<T as U>::*` examples
|
||
// above). `path_span` has the span of that path, or an empty
|
||
// span in the case of something like `<T>::Bar`.
|
||
let (mut path, path_span);
|
||
if self.eat_keyword(keywords::As) {
|
||
let path_lo = self.span;
|
||
path = self.parse_path(PathStyle::Type)?;
|
||
path_span = path_lo.to(self.prev_span);
|
||
} else {
|
||
path = ast::Path { segments: Vec::new(), span: syntax_pos::DUMMY_SP };
|
||
path_span = self.span.to(self.span);
|
||
}
|
||
|
||
// See doc comment for `unmatched_angle_bracket_count`.
|
||
self.expect(&token::Gt)?;
|
||
if self.unmatched_angle_bracket_count > 0 {
|
||
self.unmatched_angle_bracket_count -= 1;
|
||
debug!("parse_qpath: (decrement) count={:?}", self.unmatched_angle_bracket_count);
|
||
}
|
||
|
||
self.expect(&token::ModSep)?;
|
||
|
||
let qself = QSelf { ty, path_span, position: path.segments.len() };
|
||
self.parse_path_segments(&mut path.segments, style, true)?;
|
||
|
||
Ok((qself, ast::Path { segments: path.segments, span: lo.to(self.prev_span) }))
|
||
}
|
||
|
||
/// Parses simple paths.
|
||
///
|
||
/// `path = [::] segment+`
|
||
/// `segment = ident | ident[::]<args> | ident[::](args) [-> type]`
|
||
///
|
||
/// # Examples
|
||
/// `a::b::C<D>` (without disambiguator)
|
||
/// `a::b::C::<D>` (with disambiguator)
|
||
/// `Fn(Args)` (without disambiguator)
|
||
/// `Fn::(Args)` (with disambiguator)
|
||
pub fn parse_path(&mut self, style: PathStyle) -> PResult<'a, ast::Path> {
|
||
self.parse_path_common(style, true)
|
||
}
|
||
|
||
crate fn parse_path_common(&mut self, style: PathStyle, enable_warning: bool)
|
||
-> PResult<'a, ast::Path> {
|
||
maybe_whole!(self, NtPath, |path| {
|
||
if style == PathStyle::Mod &&
|
||
path.segments.iter().any(|segment| segment.args.is_some()) {
|
||
self.diagnostic().span_err(path.span, "unexpected generic arguments in path");
|
||
}
|
||
path
|
||
});
|
||
|
||
let lo = self.meta_var_span.unwrap_or(self.span);
|
||
let mut segments = Vec::new();
|
||
let mod_sep_ctxt = self.span.ctxt();
|
||
if self.eat(&token::ModSep) {
|
||
segments.push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt)));
|
||
}
|
||
self.parse_path_segments(&mut segments, style, enable_warning)?;
|
||
|
||
Ok(ast::Path { segments, span: lo.to(self.prev_span) })
|
||
}
|
||
|
||
/// Like `parse_path`, but also supports parsing `Word` meta items into paths for
|
||
/// backwards-compatibility. This is used when parsing derive macro paths in `#[derive]`
|
||
/// attributes.
|
||
pub fn parse_path_allowing_meta(&mut self, style: PathStyle) -> PResult<'a, ast::Path> {
|
||
let meta_ident = match self.token {
|
||
token::Interpolated(ref nt) => match **nt {
|
||
token::NtMeta(ref meta) => match meta.node {
|
||
ast::MetaItemKind::Word => Some(meta.ident.clone()),
|
||
_ => None,
|
||
},
|
||
_ => None,
|
||
},
|
||
_ => None,
|
||
};
|
||
if let Some(path) = meta_ident {
|
||
self.bump();
|
||
return Ok(path);
|
||
}
|
||
self.parse_path(style)
|
||
}
|
||
|
||
fn parse_path_segments(&mut self,
|
||
segments: &mut Vec<PathSegment>,
|
||
style: PathStyle,
|
||
enable_warning: bool)
|
||
-> PResult<'a, ()> {
|
||
loop {
|
||
let segment = self.parse_path_segment(style, enable_warning)?;
|
||
if style == PathStyle::Expr {
|
||
// In order to check for trailing angle brackets, we must have finished
|
||
// recursing (`parse_path_segment` can indirectly call this function),
|
||
// that is, the next token must be the highlighted part of the below example:
|
||
//
|
||
// `Foo::<Bar as Baz<T>>::Qux`
|
||
// ^ here
|
||
//
|
||
// As opposed to the below highlight (if we had only finished the first
|
||
// recursion):
|
||
//
|
||
// `Foo::<Bar as Baz<T>>::Qux`
|
||
// ^ here
|
||
//
|
||
// `PathStyle::Expr` is only provided at the root invocation and never in
|
||
// `parse_path_segment` to recurse and therefore can be checked to maintain
|
||
// this invariant.
|
||
self.check_trailing_angle_brackets(&segment, token::ModSep);
|
||
}
|
||
segments.push(segment);
|
||
|
||
if self.is_import_coupler() || !self.eat(&token::ModSep) {
|
||
return Ok(());
|
||
}
|
||
}
|
||
}
|
||
|
||
fn parse_path_segment(&mut self, style: PathStyle, enable_warning: bool)
|
||
-> PResult<'a, PathSegment> {
|
||
let ident = self.parse_path_segment_ident()?;
|
||
|
||
let is_args_start = |token: &token::Token| match *token {
|
||
token::Lt | token::BinOp(token::Shl) | token::OpenDelim(token::Paren) => true,
|
||
_ => false,
|
||
};
|
||
let check_args_start = |this: &mut Self| {
|
||
this.expected_tokens.extend_from_slice(
|
||
&[TokenType::Token(token::Lt), TokenType::Token(token::OpenDelim(token::Paren))]
|
||
);
|
||
is_args_start(&this.token)
|
||
};
|
||
|
||
Ok(if style == PathStyle::Type && check_args_start(self) ||
|
||
style != PathStyle::Mod && self.check(&token::ModSep)
|
||
&& self.look_ahead(1, |t| is_args_start(t)) {
|
||
// Generic arguments are found - `<`, `(`, `::<` or `::(`.
|
||
if self.eat(&token::ModSep) && style == PathStyle::Type && enable_warning {
|
||
self.diagnostic().struct_span_warn(self.prev_span, "unnecessary path disambiguator")
|
||
.span_label(self.prev_span, "try removing `::`").emit();
|
||
}
|
||
let lo = self.span;
|
||
|
||
// We use `style == PathStyle::Expr` to check if this is in a recursion or not. If
|
||
// it isn't, then we reset the unmatched angle bracket count as we're about to start
|
||
// parsing a new path.
|
||
if style == PathStyle::Expr {
|
||
self.unmatched_angle_bracket_count = 0;
|
||
self.max_angle_bracket_count = 0;
|
||
}
|
||
|
||
let args = if self.eat_lt() {
|
||
// `<'a, T, A = U>`
|
||
let (args, bindings) =
|
||
self.parse_generic_args_with_leaning_angle_bracket_recovery(style, lo)?;
|
||
self.expect_gt()?;
|
||
let span = lo.to(self.prev_span);
|
||
AngleBracketedArgs { args, bindings, span }.into()
|
||
} else {
|
||
// `(T, U) -> R`
|
||
self.bump(); // `(`
|
||
let (inputs, recovered) = self.parse_seq_to_before_tokens(
|
||
&[&token::CloseDelim(token::Paren)],
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
TokenExpectType::Expect,
|
||
|p| p.parse_ty())?;
|
||
if !recovered {
|
||
self.bump(); // `)`
|
||
}
|
||
let span = lo.to(self.prev_span);
|
||
let output = if self.eat(&token::RArrow) {
|
||
Some(self.parse_ty_common(false, false)?)
|
||
} else {
|
||
None
|
||
};
|
||
ParenthesizedArgs { inputs, output, span }.into()
|
||
};
|
||
|
||
PathSegment { ident, args, id: ast::DUMMY_NODE_ID }
|
||
} else {
|
||
// Generic arguments are not found.
|
||
PathSegment::from_ident(ident)
|
||
})
|
||
}
|
||
|
||
crate fn check_lifetime(&mut self) -> bool {
|
||
self.expected_tokens.push(TokenType::Lifetime);
|
||
self.token.is_lifetime()
|
||
}
|
||
|
||
/// Parses a single lifetime `'a` or panics.
|
||
crate fn expect_lifetime(&mut self) -> Lifetime {
|
||
if let Some(ident) = self.token.lifetime() {
|
||
let span = self.span;
|
||
self.bump();
|
||
Lifetime { ident: Ident::new(ident.name, span), id: ast::DUMMY_NODE_ID }
|
||
} else {
|
||
self.span_bug(self.span, "not a lifetime")
|
||
}
|
||
}
|
||
|
||
fn eat_label(&mut self) -> Option<Label> {
|
||
if let Some(ident) = self.token.lifetime() {
|
||
let span = self.span;
|
||
self.bump();
|
||
Some(Label { ident: Ident::new(ident.name, span) })
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
/// Parses mutability (`mut` or nothing).
|
||
fn parse_mutability(&mut self) -> Mutability {
|
||
if self.eat_keyword(keywords::Mut) {
|
||
Mutability::Mutable
|
||
} else {
|
||
Mutability::Immutable
|
||
}
|
||
}
|
||
|
||
fn parse_field_name(&mut self) -> PResult<'a, Ident> {
|
||
if let token::Literal(token::Integer(name), None) = self.token {
|
||
self.bump();
|
||
Ok(Ident::new(name, self.prev_span))
|
||
} else {
|
||
self.parse_ident_common(false)
|
||
}
|
||
}
|
||
|
||
/// Parse ident (COLON expr)?
|
||
fn parse_field(&mut self) -> PResult<'a, Field> {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
|
||
// Check if a colon exists one ahead. This means we're parsing a fieldname.
|
||
let (fieldname, expr, is_shorthand) = if self.look_ahead(1, |t| {
|
||
t == &token::Colon || t == &token::Eq
|
||
}) {
|
||
let fieldname = self.parse_field_name()?;
|
||
|
||
// Check for an equals token. This means the source incorrectly attempts to
|
||
// initialize a field with an eq rather than a colon.
|
||
if self.token == token::Eq {
|
||
self.diagnostic()
|
||
.struct_span_err(self.span, "expected `:`, found `=`")
|
||
.span_suggestion(
|
||
fieldname.span.shrink_to_hi().to(self.span),
|
||
"replace equals symbol with a colon",
|
||
":".to_string(),
|
||
Applicability::MachineApplicable,
|
||
)
|
||
.emit();
|
||
}
|
||
self.bump(); // `:`
|
||
(fieldname, self.parse_expr()?, false)
|
||
} else {
|
||
let fieldname = self.parse_ident_common(false)?;
|
||
|
||
// Mimic `x: x` for the `x` field shorthand.
|
||
let path = ast::Path::from_ident(fieldname);
|
||
let expr = self.mk_expr(fieldname.span, ExprKind::Path(None, path), ThinVec::new());
|
||
(fieldname, expr, true)
|
||
};
|
||
Ok(ast::Field {
|
||
ident: fieldname,
|
||
span: lo.to(expr.span),
|
||
expr,
|
||
is_shorthand,
|
||
attrs: attrs.into(),
|
||
})
|
||
}
|
||
|
||
fn mk_expr(&mut self, span: Span, node: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> {
|
||
P(Expr { node, span, attrs, id: ast::DUMMY_NODE_ID })
|
||
}
|
||
|
||
fn mk_unary(&mut self, unop: ast::UnOp, expr: P<Expr>) -> ast::ExprKind {
|
||
ExprKind::Unary(unop, expr)
|
||
}
|
||
|
||
fn mk_binary(&mut self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind {
|
||
ExprKind::Binary(binop, lhs, rhs)
|
||
}
|
||
|
||
fn mk_call(&mut self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::ExprKind {
|
||
ExprKind::Call(f, args)
|
||
}
|
||
|
||
fn mk_index(&mut self, expr: P<Expr>, idx: P<Expr>) -> ast::ExprKind {
|
||
ExprKind::Index(expr, idx)
|
||
}
|
||
|
||
fn mk_range(&mut self,
|
||
start: Option<P<Expr>>,
|
||
end: Option<P<Expr>>,
|
||
limits: RangeLimits)
|
||
-> PResult<'a, ast::ExprKind> {
|
||
if end.is_none() && limits == RangeLimits::Closed {
|
||
Err(self.span_fatal_err(self.span, Error::InclusiveRangeWithNoEnd))
|
||
} else {
|
||
Ok(ExprKind::Range(start, end, limits))
|
||
}
|
||
}
|
||
|
||
fn mk_assign_op(&mut self, binop: ast::BinOp,
|
||
lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind {
|
||
ExprKind::AssignOp(binop, lhs, rhs)
|
||
}
|
||
|
||
pub fn mk_mac_expr(&mut self, span: Span, m: Mac_, attrs: ThinVec<Attribute>) -> P<Expr> {
|
||
P(Expr {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: ExprKind::Mac(source_map::Spanned {node: m, span: span}),
|
||
span,
|
||
attrs,
|
||
})
|
||
}
|
||
|
||
fn expect_delimited_token_tree(&mut self) -> PResult<'a, (MacDelimiter, TokenStream)> {
|
||
let delim = match self.token {
|
||
token::OpenDelim(delim) => delim,
|
||
_ => {
|
||
let msg = "expected open delimiter";
|
||
let mut err = self.fatal(msg);
|
||
err.span_label(self.span, msg);
|
||
return Err(err)
|
||
}
|
||
};
|
||
let tts = match self.parse_token_tree() {
|
||
TokenTree::Delimited(_, _, tts) => tts,
|
||
_ => unreachable!(),
|
||
};
|
||
let delim = match delim {
|
||
token::Paren => MacDelimiter::Parenthesis,
|
||
token::Bracket => MacDelimiter::Bracket,
|
||
token::Brace => MacDelimiter::Brace,
|
||
token::NoDelim => self.bug("unexpected no delimiter"),
|
||
};
|
||
Ok((delim, tts.into()))
|
||
}
|
||
|
||
/// At the bottom (top?) of the precedence hierarchy,
|
||
/// Parses things like parenthesized exprs, macros, `return`, etc.
|
||
///
|
||
/// N.B., this does not parse outer attributes, and is private because it only works
|
||
/// correctly if called from `parse_dot_or_call_expr()`.
|
||
fn parse_bottom_expr(&mut self) -> PResult<'a, P<Expr>> {
|
||
maybe_whole_expr!(self);
|
||
|
||
// Outer attributes are already parsed and will be
|
||
// added to the return value after the fact.
|
||
//
|
||
// Therefore, prevent sub-parser from parsing
|
||
// attributes by giving them a empty "already parsed" list.
|
||
let mut attrs = ThinVec::new();
|
||
|
||
let lo = self.span;
|
||
let mut hi = self.span;
|
||
|
||
let ex: ExprKind;
|
||
|
||
// Note: when adding new syntax here, don't forget to adjust Token::can_begin_expr().
|
||
match self.token {
|
||
token::OpenDelim(token::Paren) => {
|
||
self.bump();
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
// (e) is parenthesized e
|
||
// (e,) is a tuple with only one field, e
|
||
let mut es = vec![];
|
||
let mut trailing_comma = false;
|
||
let mut recovered = false;
|
||
while self.token != token::CloseDelim(token::Paren) {
|
||
es.push(self.parse_expr()?);
|
||
recovered = self.expect_one_of(
|
||
&[],
|
||
&[token::Comma, token::CloseDelim(token::Paren)],
|
||
)?;
|
||
if self.eat(&token::Comma) {
|
||
trailing_comma = true;
|
||
} else {
|
||
trailing_comma = false;
|
||
break;
|
||
}
|
||
}
|
||
if !recovered {
|
||
self.bump();
|
||
}
|
||
|
||
hi = self.prev_span;
|
||
ex = if es.len() == 1 && !trailing_comma {
|
||
ExprKind::Paren(es.into_iter().nth(0).unwrap())
|
||
} else {
|
||
ExprKind::Tup(es)
|
||
};
|
||
}
|
||
token::OpenDelim(token::Brace) => {
|
||
return self.parse_block_expr(None, lo, BlockCheckMode::Default, attrs);
|
||
}
|
||
token::BinOp(token::Or) | token::OrOr => {
|
||
return self.parse_lambda_expr(attrs);
|
||
}
|
||
token::OpenDelim(token::Bracket) => {
|
||
self.bump();
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
if self.eat(&token::CloseDelim(token::Bracket)) {
|
||
// Empty vector.
|
||
ex = ExprKind::Array(Vec::new());
|
||
} else {
|
||
// Nonempty vector.
|
||
let first_expr = self.parse_expr()?;
|
||
if self.eat(&token::Semi) {
|
||
// Repeating array syntax: [ 0; 512 ]
|
||
let count = AnonConst {
|
||
id: ast::DUMMY_NODE_ID,
|
||
value: self.parse_expr()?,
|
||
};
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
ex = ExprKind::Repeat(first_expr, count);
|
||
} else if self.eat(&token::Comma) {
|
||
// Vector with two or more elements.
|
||
let remaining_exprs = self.parse_seq_to_end(
|
||
&token::CloseDelim(token::Bracket),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| Ok(p.parse_expr()?)
|
||
)?;
|
||
let mut exprs = vec![first_expr];
|
||
exprs.extend(remaining_exprs);
|
||
ex = ExprKind::Array(exprs);
|
||
} else {
|
||
// Vector with one element.
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
ex = ExprKind::Array(vec![first_expr]);
|
||
}
|
||
}
|
||
hi = self.prev_span;
|
||
}
|
||
_ => {
|
||
if self.eat_lt() {
|
||
let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
|
||
hi = path.span;
|
||
return Ok(self.mk_expr(lo.to(hi), ExprKind::Path(Some(qself), path), attrs));
|
||
}
|
||
if self.span.rust_2018() && self.check_keyword(keywords::Async)
|
||
{
|
||
if self.is_async_block() { // check for `async {` and `async move {`
|
||
return self.parse_async_block(attrs);
|
||
} else {
|
||
return self.parse_lambda_expr(attrs);
|
||
}
|
||
}
|
||
if self.check_keyword(keywords::Move) || self.check_keyword(keywords::Static) {
|
||
return self.parse_lambda_expr(attrs);
|
||
}
|
||
if self.eat_keyword(keywords::If) {
|
||
return self.parse_if_expr(attrs);
|
||
}
|
||
if self.eat_keyword(keywords::For) {
|
||
let lo = self.prev_span;
|
||
return self.parse_for_expr(None, lo, attrs);
|
||
}
|
||
if self.eat_keyword(keywords::While) {
|
||
let lo = self.prev_span;
|
||
return self.parse_while_expr(None, lo, attrs);
|
||
}
|
||
if let Some(label) = self.eat_label() {
|
||
let lo = label.ident.span;
|
||
self.expect(&token::Colon)?;
|
||
if self.eat_keyword(keywords::While) {
|
||
return self.parse_while_expr(Some(label), lo, attrs)
|
||
}
|
||
if self.eat_keyword(keywords::For) {
|
||
return self.parse_for_expr(Some(label), lo, attrs)
|
||
}
|
||
if self.eat_keyword(keywords::Loop) {
|
||
return self.parse_loop_expr(Some(label), lo, attrs)
|
||
}
|
||
if self.token == token::OpenDelim(token::Brace) {
|
||
return self.parse_block_expr(Some(label),
|
||
lo,
|
||
BlockCheckMode::Default,
|
||
attrs);
|
||
}
|
||
let msg = "expected `while`, `for`, `loop` or `{` after a label";
|
||
let mut err = self.fatal(msg);
|
||
err.span_label(self.span, msg);
|
||
return Err(err);
|
||
}
|
||
if self.eat_keyword(keywords::Loop) {
|
||
let lo = self.prev_span;
|
||
return self.parse_loop_expr(None, lo, attrs);
|
||
}
|
||
if self.eat_keyword(keywords::Continue) {
|
||
let label = self.eat_label();
|
||
let ex = ExprKind::Continue(label);
|
||
let hi = self.prev_span;
|
||
return Ok(self.mk_expr(lo.to(hi), ex, attrs));
|
||
}
|
||
if self.eat_keyword(keywords::Match) {
|
||
let match_sp = self.prev_span;
|
||
return self.parse_match_expr(attrs).map_err(|mut err| {
|
||
err.span_label(match_sp, "while parsing this match expression");
|
||
err
|
||
});
|
||
}
|
||
if self.eat_keyword(keywords::Unsafe) {
|
||
return self.parse_block_expr(
|
||
None,
|
||
lo,
|
||
BlockCheckMode::Unsafe(ast::UserProvided),
|
||
attrs);
|
||
}
|
||
if self.is_do_catch_block() {
|
||
let mut db = self.fatal("found removed `do catch` syntax");
|
||
db.help("Following RFC #2388, the new non-placeholder syntax is `try`");
|
||
return Err(db);
|
||
}
|
||
if self.is_try_block() {
|
||
let lo = self.span;
|
||
assert!(self.eat_keyword(keywords::Try));
|
||
return self.parse_try_block(lo, attrs);
|
||
}
|
||
if self.eat_keyword(keywords::Return) {
|
||
if self.token.can_begin_expr() {
|
||
let e = self.parse_expr()?;
|
||
hi = e.span;
|
||
ex = ExprKind::Ret(Some(e));
|
||
} else {
|
||
ex = ExprKind::Ret(None);
|
||
}
|
||
} else if self.eat_keyword(keywords::Break) {
|
||
let label = self.eat_label();
|
||
let e = if self.token.can_begin_expr()
|
||
&& !(self.token == token::OpenDelim(token::Brace)
|
||
&& self.restrictions.contains(
|
||
Restrictions::NO_STRUCT_LITERAL)) {
|
||
Some(self.parse_expr()?)
|
||
} else {
|
||
None
|
||
};
|
||
ex = ExprKind::Break(label, e);
|
||
hi = self.prev_span;
|
||
} else if self.eat_keyword(keywords::Yield) {
|
||
if self.token.can_begin_expr() {
|
||
let e = self.parse_expr()?;
|
||
hi = e.span;
|
||
ex = ExprKind::Yield(Some(e));
|
||
} else {
|
||
ex = ExprKind::Yield(None);
|
||
}
|
||
} else if self.token.is_keyword(keywords::Let) {
|
||
// Catch this syntax error here, instead of in `parse_ident`, so
|
||
// that we can explicitly mention that let is not to be used as an expression
|
||
let mut db = self.fatal("expected expression, found statement (`let`)");
|
||
db.span_label(self.span, "expected expression");
|
||
db.note("variable declaration using `let` is a statement");
|
||
return Err(db);
|
||
} else if self.token.is_path_start() {
|
||
let pth = self.parse_path(PathStyle::Expr)?;
|
||
|
||
// `!`, as an operator, is prefix, so we know this isn't that
|
||
if self.eat(&token::Not) {
|
||
// MACRO INVOCATION expression
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
let hi = self.prev_span;
|
||
let node = Mac_ { path: pth, tts, delim };
|
||
return Ok(self.mk_mac_expr(lo.to(hi), node, attrs))
|
||
}
|
||
if self.check(&token::OpenDelim(token::Brace)) {
|
||
// This is a struct literal, unless we're prohibited
|
||
// from parsing struct literals here.
|
||
let prohibited = self.restrictions.contains(
|
||
Restrictions::NO_STRUCT_LITERAL
|
||
);
|
||
if !prohibited {
|
||
return self.parse_struct_expr(lo, pth, attrs);
|
||
}
|
||
}
|
||
|
||
hi = pth.span;
|
||
ex = ExprKind::Path(None, pth);
|
||
} else {
|
||
if !self.unclosed_delims.is_empty() && self.check(&token::Semi) {
|
||
// Don't complain about bare semicolons after unclosed braces
|
||
// recovery in order to keep the error count down. Fixing the
|
||
// delimiters will possibly also fix the bare semicolon found in
|
||
// expression context. For example, silence the following error:
|
||
// ```
|
||
// error: expected expression, found `;`
|
||
// --> file.rs:2:13
|
||
// |
|
||
// 2 | foo(bar(;
|
||
// | ^ expected expression
|
||
// ```
|
||
self.bump();
|
||
return Ok(self.mk_expr(self.span, ExprKind::Err, ThinVec::new()));
|
||
}
|
||
match self.parse_literal_maybe_minus() {
|
||
Ok(expr) => {
|
||
hi = expr.span;
|
||
ex = expr.node.clone();
|
||
}
|
||
Err(mut err) => {
|
||
self.cancel(&mut err);
|
||
let msg = format!("expected expression, found {}",
|
||
self.this_token_descr());
|
||
let mut err = self.fatal(&msg);
|
||
err.span_label(self.span, "expected expression");
|
||
return Err(err);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
let expr = Expr { node: ex, span: lo.to(hi), id: ast::DUMMY_NODE_ID, attrs };
|
||
let expr = self.maybe_recover_from_bad_qpath(expr, true)?;
|
||
|
||
return Ok(P(expr));
|
||
}
|
||
|
||
fn parse_struct_expr(&mut self, lo: Span, pth: ast::Path, mut attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
let struct_sp = lo.to(self.prev_span);
|
||
self.bump();
|
||
let mut fields = Vec::new();
|
||
let mut base = None;
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
if self.eat(&token::DotDot) {
|
||
let exp_span = self.prev_span;
|
||
match self.parse_expr() {
|
||
Ok(e) => {
|
||
base = Some(e);
|
||
}
|
||
Err(mut e) => {
|
||
e.emit();
|
||
self.recover_stmt();
|
||
}
|
||
}
|
||
if self.token == token::Comma {
|
||
let mut err = self.sess.span_diagnostic.mut_span_err(
|
||
exp_span.to(self.prev_span),
|
||
"cannot use a comma after the base struct",
|
||
);
|
||
err.span_suggestion_short(
|
||
self.span,
|
||
"remove this comma",
|
||
String::new(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
err.note("the base struct must always be the last field");
|
||
err.emit();
|
||
self.recover_stmt();
|
||
}
|
||
break;
|
||
}
|
||
|
||
let mut recovery_field = None;
|
||
if let token::Ident(ident, _) = self.token {
|
||
if !self.token.is_reserved_ident() && self.look_ahead(1, |t| *t == token::Colon) {
|
||
// Use in case of error after field-looking code: `S { foo: () with a }`
|
||
let mut ident = ident.clone();
|
||
ident.span = self.span;
|
||
recovery_field = Some(ast::Field {
|
||
ident,
|
||
span: self.span,
|
||
expr: self.mk_expr(self.span, ExprKind::Err, ThinVec::new()),
|
||
is_shorthand: false,
|
||
attrs: ThinVec::new(),
|
||
});
|
||
}
|
||
}
|
||
let mut parsed_field = None;
|
||
match self.parse_field() {
|
||
Ok(f) => parsed_field = Some(f),
|
||
Err(mut e) => {
|
||
e.span_label(struct_sp, "while parsing this struct");
|
||
e.emit();
|
||
|
||
// If the next token is a comma, then try to parse
|
||
// what comes next as additional fields, rather than
|
||
// bailing out until next `}`.
|
||
if self.token != token::Comma {
|
||
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
|
||
if self.token != token::Comma {
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
match self.expect_one_of(&[token::Comma],
|
||
&[token::CloseDelim(token::Brace)]) {
|
||
Ok(_) => if let Some(f) = parsed_field.or(recovery_field) {
|
||
// only include the field if there's no parse error for the field name
|
||
fields.push(f);
|
||
}
|
||
Err(mut e) => {
|
||
if let Some(f) = recovery_field {
|
||
fields.push(f);
|
||
}
|
||
e.span_label(struct_sp, "while parsing this struct");
|
||
e.emit();
|
||
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
|
||
self.eat(&token::Comma);
|
||
}
|
||
}
|
||
}
|
||
|
||
let span = lo.to(self.span);
|
||
self.expect(&token::CloseDelim(token::Brace))?;
|
||
return Ok(self.mk_expr(span, ExprKind::Struct(pth, fields, base), attrs));
|
||
}
|
||
|
||
fn parse_or_use_outer_attributes(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, ThinVec<Attribute>> {
|
||
if let Some(attrs) = already_parsed_attrs {
|
||
Ok(attrs)
|
||
} else {
|
||
self.parse_outer_attributes().map(|a| a.into())
|
||
}
|
||
}
|
||
|
||
/// Parses a block or unsafe block.
|
||
fn parse_block_expr(&mut self, opt_label: Option<Label>,
|
||
lo: Span, blk_mode: BlockCheckMode,
|
||
outer_attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
|
||
let mut attrs = outer_attrs;
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
let blk = self.parse_block_tail(lo, blk_mode)?;
|
||
return Ok(self.mk_expr(blk.span, ExprKind::Block(blk, opt_label), attrs));
|
||
}
|
||
|
||
/// Parses `a.b` or `a(13)` or `a[4]` or just `a`.
|
||
fn parse_dot_or_call_expr(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
|
||
|
||
let b = self.parse_bottom_expr();
|
||
let (span, b) = self.interpolated_or_expr_span(b)?;
|
||
self.parse_dot_or_call_expr_with(b, span, attrs)
|
||
}
|
||
|
||
fn parse_dot_or_call_expr_with(&mut self,
|
||
e0: P<Expr>,
|
||
lo: Span,
|
||
mut attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
// Stitch the list of outer attributes onto the return value.
|
||
// A little bit ugly, but the best way given the current code
|
||
// structure
|
||
self.parse_dot_or_call_expr_with_(e0, lo)
|
||
.map(|expr|
|
||
expr.map(|mut expr| {
|
||
attrs.extend::<Vec<_>>(expr.attrs.into());
|
||
expr.attrs = attrs;
|
||
match expr.node {
|
||
ExprKind::If(..) | ExprKind::IfLet(..) => {
|
||
if !expr.attrs.is_empty() {
|
||
// Just point to the first attribute in there...
|
||
let span = expr.attrs[0].span;
|
||
|
||
self.span_err(span,
|
||
"attributes are not yet allowed on `if` \
|
||
expressions");
|
||
}
|
||
}
|
||
_ => {}
|
||
}
|
||
expr
|
||
})
|
||
)
|
||
}
|
||
|
||
// Assuming we have just parsed `.`, continue parsing into an expression.
|
||
fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
|
||
let segment = self.parse_path_segment(PathStyle::Expr, true)?;
|
||
self.check_trailing_angle_brackets(&segment, token::OpenDelim(token::Paren));
|
||
|
||
Ok(match self.token {
|
||
token::OpenDelim(token::Paren) => {
|
||
// Method call `expr.f()`
|
||
let mut args = self.parse_unspanned_seq(
|
||
&token::OpenDelim(token::Paren),
|
||
&token::CloseDelim(token::Paren),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| Ok(p.parse_expr()?)
|
||
)?;
|
||
args.insert(0, self_arg);
|
||
|
||
let span = lo.to(self.prev_span);
|
||
self.mk_expr(span, ExprKind::MethodCall(segment, args), ThinVec::new())
|
||
}
|
||
_ => {
|
||
// Field access `expr.f`
|
||
if let Some(args) = segment.args {
|
||
self.span_err(args.span(),
|
||
"field expressions may not have generic arguments");
|
||
}
|
||
|
||
let span = lo.to(self.prev_span);
|
||
self.mk_expr(span, ExprKind::Field(self_arg, segment.ident), ThinVec::new())
|
||
}
|
||
})
|
||
}
|
||
|
||
/// This function checks if there are trailing angle brackets and produces
|
||
/// a diagnostic to suggest removing them.
|
||
///
|
||
/// ```ignore (diagnostic)
|
||
/// let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
|
||
/// ^^ help: remove extra angle brackets
|
||
/// ```
|
||
fn check_trailing_angle_brackets(&mut self, segment: &PathSegment, end: token::Token) {
|
||
// This function is intended to be invoked after parsing a path segment where there are two
|
||
// cases:
|
||
//
|
||
// 1. A specific token is expected after the path segment.
|
||
// eg. `x.foo(`, `x.foo::<u32>(` (parenthesis - method call),
|
||
// `Foo::`, or `Foo::<Bar>::` (mod sep - continued path).
|
||
// 2. No specific token is expected after the path segment.
|
||
// eg. `x.foo` (field access)
|
||
//
|
||
// This function is called after parsing `.foo` and before parsing the token `end` (if
|
||
// present). This includes any angle bracket arguments, such as `.foo::<u32>` or
|
||
// `Foo::<Bar>`.
|
||
|
||
// We only care about trailing angle brackets if we previously parsed angle bracket
|
||
// arguments. This helps stop us incorrectly suggesting that extra angle brackets be
|
||
// removed in this case:
|
||
//
|
||
// `x.foo >> (3)` (where `x.foo` is a `u32` for example)
|
||
//
|
||
// This case is particularly tricky as we won't notice it just looking at the tokens -
|
||
// it will appear the same (in terms of upcoming tokens) as below (since the `::<u32>` will
|
||
// have already been parsed):
|
||
//
|
||
// `x.foo::<u32>>>(3)`
|
||
let parsed_angle_bracket_args = segment.args
|
||
.as_ref()
|
||
.map(|args| args.is_angle_bracketed())
|
||
.unwrap_or(false);
|
||
|
||
debug!(
|
||
"check_trailing_angle_brackets: parsed_angle_bracket_args={:?}",
|
||
parsed_angle_bracket_args,
|
||
);
|
||
if !parsed_angle_bracket_args {
|
||
return;
|
||
}
|
||
|
||
// Keep the span at the start so we can highlight the sequence of `>` characters to be
|
||
// removed.
|
||
let lo = self.span;
|
||
|
||
// We need to look-ahead to see if we have `>` characters without moving the cursor forward
|
||
// (since we might have the field access case and the characters we're eating are
|
||
// actual operators and not trailing characters - ie `x.foo >> 3`).
|
||
let mut position = 0;
|
||
|
||
// We can encounter `>` or `>>` tokens in any order, so we need to keep track of how
|
||
// many of each (so we can correctly pluralize our error messages) and continue to
|
||
// advance.
|
||
let mut number_of_shr = 0;
|
||
let mut number_of_gt = 0;
|
||
while self.look_ahead(position, |t| {
|
||
trace!("check_trailing_angle_brackets: t={:?}", t);
|
||
if *t == token::BinOp(token::BinOpToken::Shr) {
|
||
number_of_shr += 1;
|
||
true
|
||
} else if *t == token::Gt {
|
||
number_of_gt += 1;
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}) {
|
||
position += 1;
|
||
}
|
||
|
||
// If we didn't find any trailing `>` characters, then we have nothing to error about.
|
||
debug!(
|
||
"check_trailing_angle_brackets: number_of_gt={:?} number_of_shr={:?}",
|
||
number_of_gt, number_of_shr,
|
||
);
|
||
if number_of_gt < 1 && number_of_shr < 1 {
|
||
return;
|
||
}
|
||
|
||
// Finally, double check that we have our end token as otherwise this is the
|
||
// second case.
|
||
if self.look_ahead(position, |t| {
|
||
trace!("check_trailing_angle_brackets: t={:?}", t);
|
||
*t == end
|
||
}) {
|
||
// Eat from where we started until the end token so that parsing can continue
|
||
// as if we didn't have those extra angle brackets.
|
||
self.eat_to_tokens(&[&end]);
|
||
let span = lo.until(self.span);
|
||
|
||
let plural = number_of_gt > 1 || number_of_shr >= 1;
|
||
self.diagnostic()
|
||
.struct_span_err(
|
||
span,
|
||
&format!("unmatched angle bracket{}", if plural { "s" } else { "" }),
|
||
)
|
||
.span_suggestion(
|
||
span,
|
||
&format!("remove extra angle bracket{}", if plural { "s" } else { "" }),
|
||
String::new(),
|
||
Applicability::MachineApplicable,
|
||
)
|
||
.emit();
|
||
}
|
||
}
|
||
|
||
fn parse_dot_or_call_expr_with_(&mut self, e0: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
|
||
let mut e = e0;
|
||
let mut hi;
|
||
loop {
|
||
// expr?
|
||
while self.eat(&token::Question) {
|
||
let hi = self.prev_span;
|
||
e = self.mk_expr(lo.to(hi), ExprKind::Try(e), ThinVec::new());
|
||
}
|
||
|
||
// expr.f
|
||
if self.eat(&token::Dot) {
|
||
match self.token {
|
||
token::Ident(..) => {
|
||
e = self.parse_dot_suffix(e, lo)?;
|
||
}
|
||
token::Literal(token::Integer(name), _) => {
|
||
let span = self.span;
|
||
self.bump();
|
||
let field = ExprKind::Field(e, Ident::new(name, span));
|
||
e = self.mk_expr(lo.to(span), field, ThinVec::new());
|
||
}
|
||
token::Literal(token::Float(n), _suf) => {
|
||
self.bump();
|
||
let fstr = n.as_str();
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(self.prev_span, &format!("unexpected token: `{}`", n));
|
||
err.span_label(self.prev_span, "unexpected token");
|
||
if fstr.chars().all(|x| "0123456789.".contains(x)) {
|
||
let float = match fstr.parse::<f64>().ok() {
|
||
Some(f) => f,
|
||
None => continue,
|
||
};
|
||
let sugg = pprust::to_string(|s| {
|
||
use crate::print::pprust::PrintState;
|
||
s.popen()?;
|
||
s.print_expr(&e)?;
|
||
s.s.word( ".")?;
|
||
s.print_usize(float.trunc() as usize)?;
|
||
s.pclose()?;
|
||
s.s.word(".")?;
|
||
s.s.word(fstr.splitn(2, ".").last().unwrap().to_string())
|
||
});
|
||
err.span_suggestion(
|
||
lo.to(self.prev_span),
|
||
"try parenthesizing the first index",
|
||
sugg,
|
||
Applicability::MachineApplicable
|
||
);
|
||
}
|
||
return Err(err);
|
||
|
||
}
|
||
_ => {
|
||
// FIXME Could factor this out into non_fatal_unexpected or something.
|
||
let actual = self.this_token_to_string();
|
||
self.span_err(self.span, &format!("unexpected token: `{}`", actual));
|
||
}
|
||
}
|
||
continue;
|
||
}
|
||
if self.expr_is_complete(&e) { break; }
|
||
match self.token {
|
||
// expr(...)
|
||
token::OpenDelim(token::Paren) => {
|
||
let es = self.parse_unspanned_seq(
|
||
&token::OpenDelim(token::Paren),
|
||
&token::CloseDelim(token::Paren),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| Ok(p.parse_expr()?)
|
||
)?;
|
||
hi = self.prev_span;
|
||
|
||
let nd = self.mk_call(e, es);
|
||
e = self.mk_expr(lo.to(hi), nd, ThinVec::new());
|
||
}
|
||
|
||
// expr[...]
|
||
// Could be either an index expression or a slicing expression.
|
||
token::OpenDelim(token::Bracket) => {
|
||
self.bump();
|
||
let ix = self.parse_expr()?;
|
||
hi = self.span;
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
let index = self.mk_index(e, ix);
|
||
e = self.mk_expr(lo.to(hi), index, ThinVec::new())
|
||
}
|
||
_ => return Ok(e)
|
||
}
|
||
}
|
||
return Ok(e);
|
||
}
|
||
|
||
crate fn process_potential_macro_variable(&mut self) {
|
||
let (token, span) = match self.token {
|
||
token::Dollar if self.span.ctxt() != syntax_pos::hygiene::SyntaxContext::empty() &&
|
||
self.look_ahead(1, |t| t.is_ident()) => {
|
||
self.bump();
|
||
let name = match self.token {
|
||
token::Ident(ident, _) => ident,
|
||
_ => unreachable!()
|
||
};
|
||
let mut err = self.fatal(&format!("unknown macro variable `{}`", name));
|
||
err.span_label(self.span, "unknown macro variable");
|
||
err.emit();
|
||
self.bump();
|
||
return
|
||
}
|
||
token::Interpolated(ref nt) => {
|
||
self.meta_var_span = Some(self.span);
|
||
// Interpolated identifier and lifetime tokens are replaced with usual identifier
|
||
// and lifetime tokens, so the former are never encountered during normal parsing.
|
||
match **nt {
|
||
token::NtIdent(ident, is_raw) => (token::Ident(ident, is_raw), ident.span),
|
||
token::NtLifetime(ident) => (token::Lifetime(ident), ident.span),
|
||
_ => return,
|
||
}
|
||
}
|
||
_ => return,
|
||
};
|
||
self.token = token;
|
||
self.span = span;
|
||
}
|
||
|
||
/// Parses a single token tree from the input.
|
||
crate fn parse_token_tree(&mut self) -> TokenTree {
|
||
match self.token {
|
||
token::OpenDelim(..) => {
|
||
let frame = mem::replace(&mut self.token_cursor.frame,
|
||
self.token_cursor.stack.pop().unwrap());
|
||
self.span = frame.span.entire();
|
||
self.bump();
|
||
TokenTree::Delimited(
|
||
frame.span,
|
||
frame.delim,
|
||
frame.tree_cursor.stream.into(),
|
||
)
|
||
},
|
||
token::CloseDelim(_) | token::Eof => unreachable!(),
|
||
_ => {
|
||
let (token, span) = (mem::replace(&mut self.token, token::Whitespace), self.span);
|
||
self.bump();
|
||
TokenTree::Token(span, token)
|
||
}
|
||
}
|
||
}
|
||
|
||
// parse a stream of tokens into a list of TokenTree's,
|
||
// up to EOF.
|
||
pub fn parse_all_token_trees(&mut self) -> PResult<'a, Vec<TokenTree>> {
|
||
let mut tts = Vec::new();
|
||
while self.token != token::Eof {
|
||
tts.push(self.parse_token_tree());
|
||
}
|
||
Ok(tts)
|
||
}
|
||
|
||
pub fn parse_tokens(&mut self) -> TokenStream {
|
||
let mut result = Vec::new();
|
||
loop {
|
||
match self.token {
|
||
token::Eof | token::CloseDelim(..) => break,
|
||
_ => result.push(self.parse_token_tree().into()),
|
||
}
|
||
}
|
||
TokenStream::new(result)
|
||
}
|
||
|
||
/// Parse a prefix-unary-operator expr
|
||
fn parse_prefix_expr(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
|
||
let lo = self.span;
|
||
// Note: when adding new unary operators, don't forget to adjust Token::can_begin_expr()
|
||
let (hi, ex) = match self.token {
|
||
token::Not => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(lo.to(span), self.mk_unary(UnOp::Not, e))
|
||
}
|
||
// Suggest `!` for bitwise negation when encountering a `~`
|
||
token::Tilde => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
let span_of_tilde = lo;
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(span_of_tilde, "`~` cannot be used as a unary operator");
|
||
err.span_suggestion_short(
|
||
span_of_tilde,
|
||
"use `!` to perform bitwise negation",
|
||
"!".to_owned(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
err.emit();
|
||
(lo.to(span), self.mk_unary(UnOp::Not, e))
|
||
}
|
||
token::BinOp(token::Minus) => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(lo.to(span), self.mk_unary(UnOp::Neg, e))
|
||
}
|
||
token::BinOp(token::Star) => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(lo.to(span), self.mk_unary(UnOp::Deref, e))
|
||
}
|
||
token::BinOp(token::And) | token::AndAnd => {
|
||
self.expect_and()?;
|
||
let m = self.parse_mutability();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(lo.to(span), ExprKind::AddrOf(m, e))
|
||
}
|
||
token::Ident(..) if self.token.is_keyword(keywords::In) => {
|
||
self.bump();
|
||
let place = self.parse_expr_res(
|
||
Restrictions::NO_STRUCT_LITERAL,
|
||
None,
|
||
)?;
|
||
let blk = self.parse_block()?;
|
||
let span = blk.span;
|
||
let blk_expr = self.mk_expr(span, ExprKind::Block(blk, None), ThinVec::new());
|
||
(lo.to(span), ExprKind::ObsoleteInPlace(place, blk_expr))
|
||
}
|
||
token::Ident(..) if self.token.is_keyword(keywords::Box) => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(lo.to(span), ExprKind::Box(e))
|
||
}
|
||
token::Ident(..) if self.token.is_ident_named("not") => {
|
||
// `not` is just an ordinary identifier in Rust-the-language,
|
||
// but as `rustc`-the-compiler, we can issue clever diagnostics
|
||
// for confused users who really want to say `!`
|
||
let token_cannot_continue_expr = |t: &token::Token| match *t {
|
||
// These tokens can start an expression after `!`, but
|
||
// can't continue an expression after an ident
|
||
token::Ident(ident, is_raw) => token::ident_can_begin_expr(ident, is_raw),
|
||
token::Literal(..) | token::Pound => true,
|
||
token::Interpolated(ref nt) => match **nt {
|
||
token::NtIdent(..) | token::NtExpr(..) |
|
||
token::NtBlock(..) | token::NtPath(..) => true,
|
||
_ => false,
|
||
},
|
||
_ => false
|
||
};
|
||
let cannot_continue_expr = self.look_ahead(1, token_cannot_continue_expr);
|
||
if cannot_continue_expr {
|
||
self.bump();
|
||
// Emit the error ...
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(self.span,
|
||
&format!("unexpected {} after identifier",
|
||
self.this_token_descr()));
|
||
// span the `not` plus trailing whitespace to avoid
|
||
// trailing whitespace after the `!` in our suggestion
|
||
let to_replace = self.sess.source_map()
|
||
.span_until_non_whitespace(lo.to(self.span));
|
||
err.span_suggestion_short(
|
||
to_replace,
|
||
"use `!` to perform logical negation",
|
||
"!".to_owned(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
err.emit();
|
||
// —and recover! (just as if we were in the block
|
||
// for the `token::Not` arm)
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(lo.to(span), self.mk_unary(UnOp::Not, e))
|
||
} else {
|
||
return self.parse_dot_or_call_expr(Some(attrs));
|
||
}
|
||
}
|
||
_ => { return self.parse_dot_or_call_expr(Some(attrs)); }
|
||
};
|
||
return Ok(self.mk_expr(lo.to(hi), ex, attrs));
|
||
}
|
||
|
||
/// Parses an associative expression.
|
||
///
|
||
/// This parses an expression accounting for associativity and precedence of the operators in
|
||
/// the expression.
|
||
#[inline]
|
||
fn parse_assoc_expr(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
self.parse_assoc_expr_with(0, already_parsed_attrs.into())
|
||
}
|
||
|
||
/// Parses an associative expression with operators of at least `min_prec` precedence.
|
||
fn parse_assoc_expr_with(&mut self,
|
||
min_prec: usize,
|
||
lhs: LhsExpr)
|
||
-> PResult<'a, P<Expr>> {
|
||
let mut lhs = if let LhsExpr::AlreadyParsed(expr) = lhs {
|
||
expr
|
||
} else {
|
||
let attrs = match lhs {
|
||
LhsExpr::AttributesParsed(attrs) => Some(attrs),
|
||
_ => None,
|
||
};
|
||
if [token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token) {
|
||
return self.parse_prefix_range_expr(attrs);
|
||
} else {
|
||
self.parse_prefix_expr(attrs)?
|
||
}
|
||
};
|
||
|
||
if self.expr_is_complete(&lhs) {
|
||
// Semi-statement forms are odd. See https://github.com/rust-lang/rust/issues/29071
|
||
return Ok(lhs);
|
||
}
|
||
self.expected_tokens.push(TokenType::Operator);
|
||
while let Some(op) = AssocOp::from_token(&self.token) {
|
||
|
||
// Adjust the span for interpolated LHS to point to the `$lhs` token and not to what
|
||
// it refers to. Interpolated identifiers are unwrapped early and never show up here
|
||
// as `PrevTokenKind::Interpolated` so if LHS is a single identifier we always process
|
||
// it as "interpolated", it doesn't change the answer for non-interpolated idents.
|
||
let lhs_span = match (self.prev_token_kind, &lhs.node) {
|
||
(PrevTokenKind::Interpolated, _) => self.prev_span,
|
||
(PrevTokenKind::Ident, &ExprKind::Path(None, ref path))
|
||
if path.segments.len() == 1 => self.prev_span,
|
||
_ => lhs.span,
|
||
};
|
||
|
||
let cur_op_span = self.span;
|
||
let restrictions = if op.is_assign_like() {
|
||
self.restrictions & Restrictions::NO_STRUCT_LITERAL
|
||
} else {
|
||
self.restrictions
|
||
};
|
||
if op.precedence() < min_prec {
|
||
break;
|
||
}
|
||
// Check for deprecated `...` syntax
|
||
if self.token == token::DotDotDot && op == AssocOp::DotDotEq {
|
||
self.err_dotdotdot_syntax(self.span);
|
||
}
|
||
|
||
self.bump();
|
||
if op.is_comparison() {
|
||
self.check_no_chained_comparison(&lhs, &op);
|
||
}
|
||
// Special cases:
|
||
if op == AssocOp::As {
|
||
lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Cast)?;
|
||
continue
|
||
} else if op == AssocOp::Colon {
|
||
lhs = match self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Type) {
|
||
Ok(lhs) => lhs,
|
||
Err(mut err) => {
|
||
err.span_label(self.span,
|
||
"expecting a type here because of type ascription");
|
||
let cm = self.sess.source_map();
|
||
let cur_pos = cm.lookup_char_pos(self.span.lo());
|
||
let op_pos = cm.lookup_char_pos(cur_op_span.hi());
|
||
if cur_pos.line != op_pos.line {
|
||
err.span_suggestion(
|
||
cur_op_span,
|
||
"try using a semicolon",
|
||
";".to_string(),
|
||
Applicability::MaybeIncorrect // speculative
|
||
);
|
||
}
|
||
return Err(err);
|
||
}
|
||
};
|
||
continue
|
||
} else if op == AssocOp::DotDot || op == AssocOp::DotDotEq {
|
||
// If we didn’t have to handle `x..`/`x..=`, it would be pretty easy to
|
||
// generalise it to the Fixity::None code.
|
||
//
|
||
// We have 2 alternatives here: `x..y`/`x..=y` and `x..`/`x..=` The other
|
||
// two variants are handled with `parse_prefix_range_expr` call above.
|
||
let rhs = if self.is_at_start_of_range_notation_rhs() {
|
||
Some(self.parse_assoc_expr_with(op.precedence() + 1,
|
||
LhsExpr::NotYetParsed)?)
|
||
} else {
|
||
None
|
||
};
|
||
let (lhs_span, rhs_span) = (lhs.span, if let Some(ref x) = rhs {
|
||
x.span
|
||
} else {
|
||
cur_op_span
|
||
});
|
||
let limits = if op == AssocOp::DotDot {
|
||
RangeLimits::HalfOpen
|
||
} else {
|
||
RangeLimits::Closed
|
||
};
|
||
|
||
let r = self.mk_range(Some(lhs), rhs, limits)?;
|
||
lhs = self.mk_expr(lhs_span.to(rhs_span), r, ThinVec::new());
|
||
break
|
||
}
|
||
|
||
let rhs = match op.fixity() {
|
||
Fixity::Right => self.with_res(
|
||
restrictions - Restrictions::STMT_EXPR,
|
||
|this| {
|
||
this.parse_assoc_expr_with(op.precedence(),
|
||
LhsExpr::NotYetParsed)
|
||
}),
|
||
Fixity::Left => self.with_res(
|
||
restrictions - Restrictions::STMT_EXPR,
|
||
|this| {
|
||
this.parse_assoc_expr_with(op.precedence() + 1,
|
||
LhsExpr::NotYetParsed)
|
||
}),
|
||
// We currently have no non-associative operators that are not handled above by
|
||
// the special cases. The code is here only for future convenience.
|
||
Fixity::None => self.with_res(
|
||
restrictions - Restrictions::STMT_EXPR,
|
||
|this| {
|
||
this.parse_assoc_expr_with(op.precedence() + 1,
|
||
LhsExpr::NotYetParsed)
|
||
}),
|
||
}?;
|
||
|
||
// Make sure that the span of the parent node is larger than the span of lhs and rhs,
|
||
// including the attributes.
|
||
let lhs_span = lhs
|
||
.attrs
|
||
.iter()
|
||
.filter(|a| a.style == AttrStyle::Outer)
|
||
.next()
|
||
.map_or(lhs_span, |a| a.span);
|
||
let span = lhs_span.to(rhs.span);
|
||
lhs = match op {
|
||
AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide |
|
||
AssocOp::Modulus | AssocOp::LAnd | AssocOp::LOr | AssocOp::BitXor |
|
||
AssocOp::BitAnd | AssocOp::BitOr | AssocOp::ShiftLeft | AssocOp::ShiftRight |
|
||
AssocOp::Equal | AssocOp::Less | AssocOp::LessEqual | AssocOp::NotEqual |
|
||
AssocOp::Greater | AssocOp::GreaterEqual => {
|
||
let ast_op = op.to_ast_binop().unwrap();
|
||
let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs);
|
||
self.mk_expr(span, binary, ThinVec::new())
|
||
}
|
||
AssocOp::Assign =>
|
||
self.mk_expr(span, ExprKind::Assign(lhs, rhs), ThinVec::new()),
|
||
AssocOp::ObsoleteInPlace =>
|
||
self.mk_expr(span, ExprKind::ObsoleteInPlace(lhs, rhs), ThinVec::new()),
|
||
AssocOp::AssignOp(k) => {
|
||
let aop = match k {
|
||
token::Plus => BinOpKind::Add,
|
||
token::Minus => BinOpKind::Sub,
|
||
token::Star => BinOpKind::Mul,
|
||
token::Slash => BinOpKind::Div,
|
||
token::Percent => BinOpKind::Rem,
|
||
token::Caret => BinOpKind::BitXor,
|
||
token::And => BinOpKind::BitAnd,
|
||
token::Or => BinOpKind::BitOr,
|
||
token::Shl => BinOpKind::Shl,
|
||
token::Shr => BinOpKind::Shr,
|
||
};
|
||
let aopexpr = self.mk_assign_op(source_map::respan(cur_op_span, aop), lhs, rhs);
|
||
self.mk_expr(span, aopexpr, ThinVec::new())
|
||
}
|
||
AssocOp::As | AssocOp::Colon | AssocOp::DotDot | AssocOp::DotDotEq => {
|
||
self.bug("AssocOp should have been handled by special case")
|
||
}
|
||
};
|
||
|
||
if op.fixity() == Fixity::None { break }
|
||
}
|
||
Ok(lhs)
|
||
}
|
||
|
||
fn parse_assoc_op_cast(&mut self, lhs: P<Expr>, lhs_span: Span,
|
||
expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind)
|
||
-> PResult<'a, P<Expr>> {
|
||
let mk_expr = |this: &mut Self, rhs: P<Ty>| {
|
||
this.mk_expr(lhs_span.to(rhs.span), expr_kind(lhs, rhs), ThinVec::new())
|
||
};
|
||
|
||
// Save the state of the parser before parsing type normally, in case there is a
|
||
// LessThan comparison after this cast.
|
||
let parser_snapshot_before_type = self.clone();
|
||
match self.parse_ty_no_plus() {
|
||
Ok(rhs) => {
|
||
Ok(mk_expr(self, rhs))
|
||
}
|
||
Err(mut type_err) => {
|
||
// Rewind to before attempting to parse the type with generics, to recover
|
||
// from situations like `x as usize < y` in which we first tried to parse
|
||
// `usize < y` as a type with generic arguments.
|
||
let parser_snapshot_after_type = self.clone();
|
||
mem::replace(self, parser_snapshot_before_type);
|
||
|
||
match self.parse_path(PathStyle::Expr) {
|
||
Ok(path) => {
|
||
let (op_noun, op_verb) = match self.token {
|
||
token::Lt => ("comparison", "comparing"),
|
||
token::BinOp(token::Shl) => ("shift", "shifting"),
|
||
_ => {
|
||
// We can end up here even without `<` being the next token, for
|
||
// example because `parse_ty_no_plus` returns `Err` on keywords,
|
||
// but `parse_path` returns `Ok` on them due to error recovery.
|
||
// Return original error and parser state.
|
||
mem::replace(self, parser_snapshot_after_type);
|
||
return Err(type_err);
|
||
}
|
||
};
|
||
|
||
// Successfully parsed the type path leaving a `<` yet to parse.
|
||
type_err.cancel();
|
||
|
||
// Report non-fatal diagnostics, keep `x as usize` as an expression
|
||
// in AST and continue parsing.
|
||
let msg = format!("`<` is interpreted as a start of generic \
|
||
arguments for `{}`, not a {}", path, op_noun);
|
||
let mut err = self.sess.span_diagnostic.struct_span_err(self.span, &msg);
|
||
err.span_label(self.look_ahead_span(1).to(parser_snapshot_after_type.span),
|
||
"interpreted as generic arguments");
|
||
err.span_label(self.span, format!("not interpreted as {}", op_noun));
|
||
|
||
let expr = mk_expr(self, P(Ty {
|
||
span: path.span,
|
||
node: TyKind::Path(None, path),
|
||
id: ast::DUMMY_NODE_ID
|
||
}));
|
||
|
||
let expr_str = self.sess.source_map().span_to_snippet(expr.span)
|
||
.unwrap_or_else(|_| pprust::expr_to_string(&expr));
|
||
err.span_suggestion(
|
||
expr.span,
|
||
&format!("try {} the cast value", op_verb),
|
||
format!("({})", expr_str),
|
||
Applicability::MachineApplicable
|
||
);
|
||
err.emit();
|
||
|
||
Ok(expr)
|
||
}
|
||
Err(mut path_err) => {
|
||
// Couldn't parse as a path, return original error and parser state.
|
||
path_err.cancel();
|
||
mem::replace(self, parser_snapshot_after_type);
|
||
Err(type_err)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Produce an error if comparison operators are chained (RFC #558).
|
||
/// We only need to check lhs, not rhs, because all comparison ops
|
||
/// have same precedence and are left-associative
|
||
fn check_no_chained_comparison(&mut self, lhs: &Expr, outer_op: &AssocOp) {
|
||
debug_assert!(outer_op.is_comparison(),
|
||
"check_no_chained_comparison: {:?} is not comparison",
|
||
outer_op);
|
||
match lhs.node {
|
||
ExprKind::Binary(op, _, _) if op.node.is_comparison() => {
|
||
// respan to include both operators
|
||
let op_span = op.span.to(self.span);
|
||
let mut err = self.diagnostic().struct_span_err(op_span,
|
||
"chained comparison operators require parentheses");
|
||
if op.node == BinOpKind::Lt &&
|
||
*outer_op == AssocOp::Less || // Include `<` to provide this recommendation
|
||
*outer_op == AssocOp::Greater // even in a case like the following:
|
||
{ // Foo<Bar<Baz<Qux, ()>>>
|
||
err.help(
|
||
"use `::<...>` instead of `<...>` if you meant to specify type arguments");
|
||
err.help("or use `(...)` if you meant to specify fn arguments");
|
||
}
|
||
err.emit();
|
||
}
|
||
_ => {}
|
||
}
|
||
}
|
||
|
||
/// Parse prefix-forms of range notation: `..expr`, `..`, `..=expr`
|
||
fn parse_prefix_range_expr(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
// Check for deprecated `...` syntax
|
||
if self.token == token::DotDotDot {
|
||
self.err_dotdotdot_syntax(self.span);
|
||
}
|
||
|
||
debug_assert!([token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token),
|
||
"parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq",
|
||
self.token);
|
||
let tok = self.token.clone();
|
||
let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
|
||
let lo = self.span;
|
||
let mut hi = self.span;
|
||
self.bump();
|
||
let opt_end = if self.is_at_start_of_range_notation_rhs() {
|
||
// RHS must be parsed with more associativity than the dots.
|
||
let next_prec = AssocOp::from_token(&tok).unwrap().precedence() + 1;
|
||
Some(self.parse_assoc_expr_with(next_prec,
|
||
LhsExpr::NotYetParsed)
|
||
.map(|x|{
|
||
hi = x.span;
|
||
x
|
||
})?)
|
||
} else {
|
||
None
|
||
};
|
||
let limits = if tok == token::DotDot {
|
||
RangeLimits::HalfOpen
|
||
} else {
|
||
RangeLimits::Closed
|
||
};
|
||
|
||
let r = self.mk_range(None, opt_end, limits)?;
|
||
Ok(self.mk_expr(lo.to(hi), r, attrs))
|
||
}
|
||
|
||
fn is_at_start_of_range_notation_rhs(&self) -> bool {
|
||
if self.token.can_begin_expr() {
|
||
// parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
|
||
if self.token == token::OpenDelim(token::Brace) {
|
||
return !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
|
||
}
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
/// Parses an `if` or `if let` expression (`if` token already eaten).
|
||
fn parse_if_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
if self.check_keyword(keywords::Let) {
|
||
return self.parse_if_let_expr(attrs);
|
||
}
|
||
let lo = self.prev_span;
|
||
let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
||
|
||
// Verify that the parsed `if` condition makes sense as a condition. If it is a block, then
|
||
// verify that the last statement is either an implicit return (no `;`) or an explicit
|
||
// return. This won't catch blocks with an explicit `return`, but that would be caught by
|
||
// the dead code lint.
|
||
if self.eat_keyword(keywords::Else) || !cond.returns() {
|
||
let sp = self.sess.source_map().next_point(lo);
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "missing condition for `if` statement");
|
||
err.span_label(sp, "expected if condition here");
|
||
return Err(err)
|
||
}
|
||
let not_block = self.token != token::OpenDelim(token::Brace);
|
||
let thn = self.parse_block().map_err(|mut err| {
|
||
if not_block {
|
||
err.span_label(lo, "this `if` statement has a condition, but no block");
|
||
}
|
||
err
|
||
})?;
|
||
let mut els: Option<P<Expr>> = None;
|
||
let mut hi = thn.span;
|
||
if self.eat_keyword(keywords::Else) {
|
||
let elexpr = self.parse_else_expr()?;
|
||
hi = elexpr.span;
|
||
els = Some(elexpr);
|
||
}
|
||
Ok(self.mk_expr(lo.to(hi), ExprKind::If(cond, thn, els), attrs))
|
||
}
|
||
|
||
/// Parses an `if let` expression (`if` token already eaten).
|
||
fn parse_if_let_expr(&mut self, attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
let lo = self.prev_span;
|
||
self.expect_keyword(keywords::Let)?;
|
||
let pats = self.parse_pats()?;
|
||
self.expect(&token::Eq)?;
|
||
let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
||
let thn = self.parse_block()?;
|
||
let (hi, els) = if self.eat_keyword(keywords::Else) {
|
||
let expr = self.parse_else_expr()?;
|
||
(expr.span, Some(expr))
|
||
} else {
|
||
(thn.span, None)
|
||
};
|
||
Ok(self.mk_expr(lo.to(hi), ExprKind::IfLet(pats, expr, thn, els), attrs))
|
||
}
|
||
|
||
/// Parses `move |args| expr`.
|
||
fn parse_lambda_expr(&mut self,
|
||
attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>>
|
||
{
|
||
let lo = self.span;
|
||
let movability = if self.eat_keyword(keywords::Static) {
|
||
Movability::Static
|
||
} else {
|
||
Movability::Movable
|
||
};
|
||
let asyncness = if self.span.rust_2018() {
|
||
self.parse_asyncness()
|
||
} else {
|
||
IsAsync::NotAsync
|
||
};
|
||
let capture_clause = if self.eat_keyword(keywords::Move) {
|
||
CaptureBy::Value
|
||
} else {
|
||
CaptureBy::Ref
|
||
};
|
||
let decl = self.parse_fn_block_decl()?;
|
||
let decl_hi = self.prev_span;
|
||
let body = match decl.output {
|
||
FunctionRetTy::Default(_) => {
|
||
let restrictions = self.restrictions - Restrictions::STMT_EXPR;
|
||
self.parse_expr_res(restrictions, None)?
|
||
},
|
||
_ => {
|
||
// If an explicit return type is given, require a
|
||
// block to appear (RFC 968).
|
||
let body_lo = self.span;
|
||
self.parse_block_expr(None, body_lo, BlockCheckMode::Default, ThinVec::new())?
|
||
}
|
||
};
|
||
|
||
Ok(self.mk_expr(
|
||
lo.to(body.span),
|
||
ExprKind::Closure(capture_clause, asyncness, movability, decl, body, lo.to(decl_hi)),
|
||
attrs))
|
||
}
|
||
|
||
// `else` token already eaten
|
||
fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
|
||
if self.eat_keyword(keywords::If) {
|
||
return self.parse_if_expr(ThinVec::new());
|
||
} else {
|
||
let blk = self.parse_block()?;
|
||
return Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None), ThinVec::new()));
|
||
}
|
||
}
|
||
|
||
/// Parse a 'for' .. 'in' expression ('for' token already eaten)
|
||
fn parse_for_expr(&mut self, opt_label: Option<Label>,
|
||
span_lo: Span,
|
||
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
// Parse: `for <src_pat> in <src_expr> <src_loop_block>`
|
||
|
||
let pat = self.parse_top_level_pat()?;
|
||
if !self.eat_keyword(keywords::In) {
|
||
let in_span = self.prev_span.between(self.span);
|
||
let mut err = self.sess.span_diagnostic
|
||
.struct_span_err(in_span, "missing `in` in `for` loop");
|
||
err.span_suggestion_short(
|
||
in_span, "try adding `in` here", " in ".into(),
|
||
// has been misleading, at least in the past (closed Issue #48492)
|
||
Applicability::MaybeIncorrect
|
||
);
|
||
err.emit();
|
||
}
|
||
let in_span = self.prev_span;
|
||
if self.eat_keyword(keywords::In) {
|
||
// a common typo: `for _ in in bar {}`
|
||
let mut err = self.sess.span_diagnostic.struct_span_err(
|
||
self.prev_span,
|
||
"expected iterable, found keyword `in`",
|
||
);
|
||
err.span_suggestion_short(
|
||
in_span.until(self.prev_span),
|
||
"remove the duplicated `in`",
|
||
String::new(),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
err.note("if you meant to use emplacement syntax, it is obsolete (for now, anyway)");
|
||
err.note("for more information on the status of emplacement syntax, see <\
|
||
https://github.com/rust-lang/rust/issues/27779#issuecomment-378416911>");
|
||
err.emit();
|
||
}
|
||
let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
||
let (iattrs, loop_block) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
|
||
let hi = self.prev_span;
|
||
Ok(self.mk_expr(span_lo.to(hi), ExprKind::ForLoop(pat, expr, loop_block, opt_label), attrs))
|
||
}
|
||
|
||
/// Parses a `while` or `while let` expression (`while` token already eaten).
|
||
fn parse_while_expr(&mut self, opt_label: Option<Label>,
|
||
span_lo: Span,
|
||
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
if self.token.is_keyword(keywords::Let) {
|
||
return self.parse_while_let_expr(opt_label, span_lo, attrs);
|
||
}
|
||
let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
||
let (iattrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
let span = span_lo.to(body.span);
|
||
return Ok(self.mk_expr(span, ExprKind::While(cond, body, opt_label), attrs));
|
||
}
|
||
|
||
/// Parses a `while let` expression (`while` token already eaten).
|
||
fn parse_while_let_expr(&mut self, opt_label: Option<Label>,
|
||
span_lo: Span,
|
||
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
self.expect_keyword(keywords::Let)?;
|
||
let pats = self.parse_pats()?;
|
||
self.expect(&token::Eq)?;
|
||
let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
||
let (iattrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
let span = span_lo.to(body.span);
|
||
return Ok(self.mk_expr(span, ExprKind::WhileLet(pats, expr, body, opt_label), attrs));
|
||
}
|
||
|
||
// parse `loop {...}`, `loop` token already eaten
|
||
fn parse_loop_expr(&mut self, opt_label: Option<Label>,
|
||
span_lo: Span,
|
||
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
let (iattrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
let span = span_lo.to(body.span);
|
||
Ok(self.mk_expr(span, ExprKind::Loop(body, opt_label), attrs))
|
||
}
|
||
|
||
/// Parses an `async move {...}` expression.
|
||
pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>>
|
||
{
|
||
let span_lo = self.span;
|
||
self.expect_keyword(keywords::Async)?;
|
||
let capture_clause = if self.eat_keyword(keywords::Move) {
|
||
CaptureBy::Value
|
||
} else {
|
||
CaptureBy::Ref
|
||
};
|
||
let (iattrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
Ok(self.mk_expr(
|
||
span_lo.to(body.span),
|
||
ExprKind::Async(capture_clause, ast::DUMMY_NODE_ID, body), attrs))
|
||
}
|
||
|
||
/// Parses a `try {...}` expression (`try` token already eaten).
|
||
fn parse_try_block(&mut self, span_lo: Span, mut attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>>
|
||
{
|
||
let (iattrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
Ok(self.mk_expr(span_lo.to(body.span), ExprKind::TryBlock(body), attrs))
|
||
}
|
||
|
||
// `match` token already eaten
|
||
fn parse_match_expr(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
let match_span = self.prev_span;
|
||
let lo = self.prev_span;
|
||
let discriminant = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL,
|
||
None)?;
|
||
if let Err(mut e) = self.expect(&token::OpenDelim(token::Brace)) {
|
||
if self.token == token::Token::Semi {
|
||
e.span_suggestion_short(
|
||
match_span,
|
||
"try removing this `match`",
|
||
String::new(),
|
||
Applicability::MaybeIncorrect // speculative
|
||
);
|
||
}
|
||
return Err(e)
|
||
}
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
let mut arms: Vec<Arm> = Vec::new();
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
match self.parse_arm() {
|
||
Ok(arm) => arms.push(arm),
|
||
Err(mut e) => {
|
||
// Recover by skipping to the end of the block.
|
||
e.emit();
|
||
self.recover_stmt();
|
||
let span = lo.to(self.span);
|
||
if self.token == token::CloseDelim(token::Brace) {
|
||
self.bump();
|
||
}
|
||
return Ok(self.mk_expr(span, ExprKind::Match(discriminant, arms), attrs));
|
||
}
|
||
}
|
||
}
|
||
let hi = self.span;
|
||
self.bump();
|
||
return Ok(self.mk_expr(lo.to(hi), ExprKind::Match(discriminant, arms), attrs));
|
||
}
|
||
|
||
crate fn parse_arm(&mut self) -> PResult<'a, Arm> {
|
||
maybe_whole!(self, NtArm, |x| x);
|
||
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let pats = self.parse_pats()?;
|
||
let guard = if self.eat_keyword(keywords::If) {
|
||
Some(Guard::If(self.parse_expr()?))
|
||
} else {
|
||
None
|
||
};
|
||
let arrow_span = self.span;
|
||
self.expect(&token::FatArrow)?;
|
||
let arm_start_span = self.span;
|
||
|
||
let expr = self.parse_expr_res(Restrictions::STMT_EXPR, None)
|
||
.map_err(|mut err| {
|
||
err.span_label(arrow_span, "while parsing the `match` arm starting here");
|
||
err
|
||
})?;
|
||
|
||
let require_comma = classify::expr_requires_semi_to_be_stmt(&expr)
|
||
&& self.token != token::CloseDelim(token::Brace);
|
||
|
||
if require_comma {
|
||
let cm = self.sess.source_map();
|
||
self.expect_one_of(&[token::Comma], &[token::CloseDelim(token::Brace)])
|
||
.map_err(|mut err| {
|
||
match (cm.span_to_lines(expr.span), cm.span_to_lines(arm_start_span)) {
|
||
(Ok(ref expr_lines), Ok(ref arm_start_lines))
|
||
if arm_start_lines.lines[0].end_col == expr_lines.lines[0].end_col
|
||
&& expr_lines.lines.len() == 2
|
||
&& self.token == token::FatArrow => {
|
||
// We check whether there's any trailing code in the parse span,
|
||
// if there isn't, we very likely have the following:
|
||
//
|
||
// X | &Y => "y"
|
||
// | -- - missing comma
|
||
// | |
|
||
// | arrow_span
|
||
// X | &X => "x"
|
||
// | - ^^ self.span
|
||
// | |
|
||
// | parsed until here as `"y" & X`
|
||
err.span_suggestion_short(
|
||
cm.next_point(arm_start_span),
|
||
"missing a comma here to end this `match` arm",
|
||
",".to_owned(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
}
|
||
_ => {
|
||
err.span_label(arrow_span,
|
||
"while parsing the `match` arm starting here");
|
||
}
|
||
}
|
||
err
|
||
})?;
|
||
} else {
|
||
self.eat(&token::Comma);
|
||
}
|
||
|
||
Ok(ast::Arm {
|
||
attrs,
|
||
pats,
|
||
guard,
|
||
body: expr,
|
||
})
|
||
}
|
||
|
||
/// Parses an expression.
|
||
#[inline]
|
||
pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
|
||
self.parse_expr_res(Restrictions::empty(), None)
|
||
}
|
||
|
||
/// Evaluates the closure with restrictions in place.
|
||
///
|
||
/// Afters the closure is evaluated, restrictions are reset.
|
||
fn with_res<F, T>(&mut self, r: Restrictions, f: F) -> T
|
||
where F: FnOnce(&mut Self) -> T
|
||
{
|
||
let old = self.restrictions;
|
||
self.restrictions = r;
|
||
let r = f(self);
|
||
self.restrictions = old;
|
||
return r;
|
||
|
||
}
|
||
|
||
/// Parses an expression, subject to the given restrictions.
|
||
#[inline]
|
||
fn parse_expr_res(&mut self, r: Restrictions,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
self.with_res(r, |this| this.parse_assoc_expr(already_parsed_attrs))
|
||
}
|
||
|
||
/// Parses the RHS of a local variable declaration (e.g., '= 14;').
|
||
fn parse_initializer(&mut self, skip_eq: bool) -> PResult<'a, Option<P<Expr>>> {
|
||
if self.eat(&token::Eq) {
|
||
Ok(Some(self.parse_expr()?))
|
||
} else if skip_eq {
|
||
Ok(Some(self.parse_expr()?))
|
||
} else {
|
||
Ok(None)
|
||
}
|
||
}
|
||
|
||
/// Parses patterns, separated by '|' s.
|
||
fn parse_pats(&mut self) -> PResult<'a, Vec<P<Pat>>> {
|
||
// Allow a '|' before the pats (RFC 1925 + RFC 2530)
|
||
self.eat(&token::BinOp(token::Or));
|
||
|
||
let mut pats = Vec::new();
|
||
loop {
|
||
pats.push(self.parse_top_level_pat()?);
|
||
|
||
if self.token == token::OrOr {
|
||
let mut err = self.struct_span_err(self.span,
|
||
"unexpected token `||` after pattern");
|
||
err.span_suggestion(
|
||
self.span,
|
||
"use a single `|` to specify multiple patterns",
|
||
"|".to_owned(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
err.emit();
|
||
self.bump();
|
||
} else if self.eat(&token::BinOp(token::Or)) {
|
||
// This is a No-op. Continue the loop to parse the next
|
||
// pattern.
|
||
} else {
|
||
return Ok(pats);
|
||
}
|
||
};
|
||
}
|
||
|
||
// Parses a parenthesized list of patterns like
|
||
// `()`, `(p)`, `(p,)`, `(p, q)`, or `(p, .., q)`. Returns:
|
||
// - a vector of the patterns that were parsed
|
||
// - an option indicating the index of the `..` element
|
||
// - a boolean indicating whether a trailing comma was present.
|
||
// Trailing commas are significant because (p) and (p,) are different patterns.
|
||
fn parse_parenthesized_pat_list(&mut self) -> PResult<'a, (Vec<P<Pat>>, Option<usize>, bool)> {
|
||
self.expect(&token::OpenDelim(token::Paren))?;
|
||
let result = self.parse_pat_list()?;
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
Ok(result)
|
||
}
|
||
|
||
fn parse_pat_list(&mut self) -> PResult<'a, (Vec<P<Pat>>, Option<usize>, bool)> {
|
||
let mut fields = Vec::new();
|
||
let mut ddpos = None;
|
||
let mut trailing_comma = false;
|
||
loop {
|
||
if self.eat(&token::DotDot) {
|
||
if ddpos.is_none() {
|
||
ddpos = Some(fields.len());
|
||
} else {
|
||
// Emit a friendly error, ignore `..` and continue parsing
|
||
self.struct_span_err(
|
||
self.prev_span,
|
||
"`..` can only be used once per tuple or tuple struct pattern",
|
||
)
|
||
.span_label(self.prev_span, "can only be used once per pattern")
|
||
.emit();
|
||
}
|
||
} else if !self.check(&token::CloseDelim(token::Paren)) {
|
||
fields.push(self.parse_pat(None)?);
|
||
} else {
|
||
break
|
||
}
|
||
|
||
trailing_comma = self.eat(&token::Comma);
|
||
if !trailing_comma {
|
||
break
|
||
}
|
||
}
|
||
|
||
if ddpos == Some(fields.len()) && trailing_comma {
|
||
// `..` needs to be followed by `)` or `, pat`, `..,)` is disallowed.
|
||
let msg = "trailing comma is not permitted after `..`";
|
||
self.struct_span_err(self.prev_span, msg)
|
||
.span_label(self.prev_span, msg)
|
||
.emit();
|
||
}
|
||
|
||
Ok((fields, ddpos, trailing_comma))
|
||
}
|
||
|
||
fn parse_pat_vec_elements(
|
||
&mut self,
|
||
) -> PResult<'a, (Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>)> {
|
||
let mut before = Vec::new();
|
||
let mut slice = None;
|
||
let mut after = Vec::new();
|
||
let mut first = true;
|
||
let mut before_slice = true;
|
||
|
||
while self.token != token::CloseDelim(token::Bracket) {
|
||
if first {
|
||
first = false;
|
||
} else {
|
||
self.expect(&token::Comma)?;
|
||
|
||
if self.token == token::CloseDelim(token::Bracket)
|
||
&& (before_slice || !after.is_empty()) {
|
||
break
|
||
}
|
||
}
|
||
|
||
if before_slice {
|
||
if self.eat(&token::DotDot) {
|
||
|
||
if self.check(&token::Comma) ||
|
||
self.check(&token::CloseDelim(token::Bracket)) {
|
||
slice = Some(P(Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Wild,
|
||
span: self.prev_span,
|
||
}));
|
||
before_slice = false;
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
|
||
let subpat = self.parse_pat(None)?;
|
||
if before_slice && self.eat(&token::DotDot) {
|
||
slice = Some(subpat);
|
||
before_slice = false;
|
||
} else if before_slice {
|
||
before.push(subpat);
|
||
} else {
|
||
after.push(subpat);
|
||
}
|
||
}
|
||
|
||
Ok((before, slice, after))
|
||
}
|
||
|
||
fn parse_pat_field(
|
||
&mut self,
|
||
lo: Span,
|
||
attrs: Vec<Attribute>
|
||
) -> PResult<'a, source_map::Spanned<ast::FieldPat>> {
|
||
// Check if a colon exists one ahead. This means we're parsing a fieldname.
|
||
let hi;
|
||
let (subpat, fieldname, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
|
||
// Parsing a pattern of the form "fieldname: pat"
|
||
let fieldname = self.parse_field_name()?;
|
||
self.bump();
|
||
let pat = self.parse_pat(None)?;
|
||
hi = pat.span;
|
||
(pat, fieldname, false)
|
||
} else {
|
||
// Parsing a pattern of the form "(box) (ref) (mut) fieldname"
|
||
let is_box = self.eat_keyword(keywords::Box);
|
||
let boxed_span = self.span;
|
||
let is_ref = self.eat_keyword(keywords::Ref);
|
||
let is_mut = self.eat_keyword(keywords::Mut);
|
||
let fieldname = self.parse_ident()?;
|
||
hi = self.prev_span;
|
||
|
||
let bind_type = match (is_ref, is_mut) {
|
||
(true, true) => BindingMode::ByRef(Mutability::Mutable),
|
||
(true, false) => BindingMode::ByRef(Mutability::Immutable),
|
||
(false, true) => BindingMode::ByValue(Mutability::Mutable),
|
||
(false, false) => BindingMode::ByValue(Mutability::Immutable),
|
||
};
|
||
let fieldpat = P(Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Ident(bind_type, fieldname, None),
|
||
span: boxed_span.to(hi),
|
||
});
|
||
|
||
let subpat = if is_box {
|
||
P(Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Box(fieldpat),
|
||
span: lo.to(hi),
|
||
})
|
||
} else {
|
||
fieldpat
|
||
};
|
||
(subpat, fieldname, true)
|
||
};
|
||
|
||
Ok(source_map::Spanned {
|
||
span: lo.to(hi),
|
||
node: ast::FieldPat {
|
||
ident: fieldname,
|
||
pat: subpat,
|
||
is_shorthand,
|
||
attrs: attrs.into(),
|
||
}
|
||
})
|
||
}
|
||
|
||
/// Parses the fields of a struct-like pattern.
|
||
fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<source_map::Spanned<ast::FieldPat>>, bool)> {
|
||
let mut fields = Vec::new();
|
||
let mut etc = false;
|
||
let mut ate_comma = true;
|
||
let mut delayed_err: Option<DiagnosticBuilder<'a>> = None;
|
||
let mut etc_span = None;
|
||
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
|
||
// check that a comma comes after every field
|
||
if !ate_comma {
|
||
let err = self.struct_span_err(self.prev_span, "expected `,`");
|
||
if let Some(mut delayed) = delayed_err {
|
||
delayed.emit();
|
||
}
|
||
return Err(err);
|
||
}
|
||
ate_comma = false;
|
||
|
||
if self.check(&token::DotDot) || self.token == token::DotDotDot {
|
||
etc = true;
|
||
let mut etc_sp = self.span;
|
||
|
||
if self.token == token::DotDotDot { // Issue #46718
|
||
// Accept `...` as if it were `..` to avoid further errors
|
||
let mut err = self.struct_span_err(self.span,
|
||
"expected field pattern, found `...`");
|
||
err.span_suggestion(
|
||
self.span,
|
||
"to omit remaining fields, use one fewer `.`",
|
||
"..".to_owned(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
err.emit();
|
||
}
|
||
self.bump(); // `..` || `...`
|
||
|
||
if self.token == token::CloseDelim(token::Brace) {
|
||
etc_span = Some(etc_sp);
|
||
break;
|
||
}
|
||
let token_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!("expected `}}`, found {}", token_str));
|
||
|
||
err.span_label(self.span, "expected `}`");
|
||
let mut comma_sp = None;
|
||
if self.token == token::Comma { // Issue #49257
|
||
etc_sp = etc_sp.to(self.sess.source_map().span_until_non_whitespace(self.span));
|
||
err.span_label(etc_sp,
|
||
"`..` must be at the end and cannot have a trailing comma");
|
||
comma_sp = Some(self.span);
|
||
self.bump();
|
||
ate_comma = true;
|
||
}
|
||
|
||
etc_span = Some(etc_sp.until(self.span));
|
||
if self.token == token::CloseDelim(token::Brace) {
|
||
// If the struct looks otherwise well formed, recover and continue.
|
||
if let Some(sp) = comma_sp {
|
||
err.span_suggestion_short(
|
||
sp,
|
||
"remove this comma",
|
||
String::new(),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
}
|
||
err.emit();
|
||
break;
|
||
} else if self.token.is_ident() && ate_comma {
|
||
// Accept fields coming after `..,`.
|
||
// This way we avoid "pattern missing fields" errors afterwards.
|
||
// We delay this error until the end in order to have a span for a
|
||
// suggested fix.
|
||
if let Some(mut delayed_err) = delayed_err {
|
||
delayed_err.emit();
|
||
return Err(err);
|
||
} else {
|
||
delayed_err = Some(err);
|
||
}
|
||
} else {
|
||
if let Some(mut err) = delayed_err {
|
||
err.emit();
|
||
}
|
||
return Err(err);
|
||
}
|
||
}
|
||
|
||
fields.push(match self.parse_pat_field(lo, attrs) {
|
||
Ok(field) => field,
|
||
Err(err) => {
|
||
if let Some(mut delayed_err) = delayed_err {
|
||
delayed_err.emit();
|
||
}
|
||
return Err(err);
|
||
}
|
||
});
|
||
ate_comma = self.eat(&token::Comma);
|
||
}
|
||
|
||
if let Some(mut err) = delayed_err {
|
||
if let Some(etc_span) = etc_span {
|
||
err.multipart_suggestion(
|
||
"move the `..` to the end of the field list",
|
||
vec![
|
||
(etc_span, String::new()),
|
||
(self.span, format!("{}.. }}", if ate_comma { "" } else { ", " })),
|
||
],
|
||
Applicability::MachineApplicable,
|
||
);
|
||
}
|
||
err.emit();
|
||
}
|
||
return Ok((fields, etc));
|
||
}
|
||
|
||
fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
|
||
if self.token.is_path_start() {
|
||
let lo = self.span;
|
||
let (qself, path) = if self.eat_lt() {
|
||
// Parse a qualified path
|
||
let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
|
||
(Some(qself), path)
|
||
} else {
|
||
// Parse an unqualified path
|
||
(None, self.parse_path(PathStyle::Expr)?)
|
||
};
|
||
let hi = self.prev_span;
|
||
Ok(self.mk_expr(lo.to(hi), ExprKind::Path(qself, path), ThinVec::new()))
|
||
} else {
|
||
self.parse_literal_maybe_minus()
|
||
}
|
||
}
|
||
|
||
// helper function to decide whether to parse as ident binding or to try to do
|
||
// something more complex like range patterns
|
||
fn parse_as_ident(&mut self) -> bool {
|
||
self.look_ahead(1, |t| match *t {
|
||
token::OpenDelim(token::Paren) | token::OpenDelim(token::Brace) |
|
||
token::DotDotDot | token::DotDotEq | token::ModSep | token::Not => Some(false),
|
||
// ensure slice patterns [a, b.., c] and [a, b, c..] don't go into the
|
||
// range pattern branch
|
||
token::DotDot => None,
|
||
_ => Some(true),
|
||
}).unwrap_or_else(|| self.look_ahead(2, |t| match *t {
|
||
token::Comma | token::CloseDelim(token::Bracket) => true,
|
||
_ => false,
|
||
}))
|
||
}
|
||
|
||
/// A wrapper around `parse_pat` with some special error handling for the
|
||
/// "top-level" patterns in a match arm, `for` loop, `let`, &c. (in contrast
|
||
/// to subpatterns within such).
|
||
fn parse_top_level_pat(&mut self) -> PResult<'a, P<Pat>> {
|
||
let pat = self.parse_pat(None)?;
|
||
if self.token == token::Comma {
|
||
// An unexpected comma after a top-level pattern is a clue that the
|
||
// user (perhaps more accustomed to some other language) forgot the
|
||
// parentheses in what should have been a tuple pattern; return a
|
||
// suggestion-enhanced error here rather than choking on the comma
|
||
// later.
|
||
let comma_span = self.span;
|
||
self.bump();
|
||
if let Err(mut err) = self.parse_pat_list() {
|
||
// We didn't expect this to work anyway; we just wanted
|
||
// to advance to the end of the comma-sequence so we know
|
||
// the span to suggest parenthesizing
|
||
err.cancel();
|
||
}
|
||
let seq_span = pat.span.to(self.prev_span);
|
||
let mut err = self.struct_span_err(comma_span,
|
||
"unexpected `,` in pattern");
|
||
if let Ok(seq_snippet) = self.sess.source_map().span_to_snippet(seq_span) {
|
||
err.span_suggestion(
|
||
seq_span,
|
||
"try adding parentheses to match on a tuple..",
|
||
format!("({})", seq_snippet),
|
||
Applicability::MachineApplicable
|
||
).span_suggestion(
|
||
seq_span,
|
||
"..or a vertical bar to match on multiple alternatives",
|
||
format!("{}", seq_snippet.replace(",", " |")),
|
||
Applicability::MachineApplicable
|
||
);
|
||
}
|
||
return Err(err);
|
||
}
|
||
Ok(pat)
|
||
}
|
||
|
||
/// Parses a pattern.
|
||
pub fn parse_pat(&mut self, expected: Option<&'static str>) -> PResult<'a, P<Pat>> {
|
||
self.parse_pat_with_range_pat(true, expected)
|
||
}
|
||
|
||
/// Parses a pattern, with a setting whether modern range patterns (e.g., `a..=b`, `a..b` are
|
||
/// allowed).
|
||
fn parse_pat_with_range_pat(
|
||
&mut self,
|
||
allow_range_pat: bool,
|
||
expected: Option<&'static str>,
|
||
) -> PResult<'a, P<Pat>> {
|
||
maybe_whole!(self, NtPat, |x| x);
|
||
|
||
let lo = self.span;
|
||
let pat;
|
||
match self.token {
|
||
token::BinOp(token::And) | token::AndAnd => {
|
||
// Parse &pat / &mut pat
|
||
self.expect_and()?;
|
||
let mutbl = self.parse_mutability();
|
||
if let token::Lifetime(ident) = self.token {
|
||
let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern",
|
||
ident));
|
||
err.span_label(self.span, "unexpected lifetime");
|
||
return Err(err);
|
||
}
|
||
let subpat = self.parse_pat_with_range_pat(false, expected)?;
|
||
pat = PatKind::Ref(subpat, mutbl);
|
||
}
|
||
token::OpenDelim(token::Paren) => {
|
||
// Parse (pat,pat,pat,...) as tuple pattern
|
||
let (fields, ddpos, trailing_comma) = self.parse_parenthesized_pat_list()?;
|
||
pat = if fields.len() == 1 && ddpos.is_none() && !trailing_comma {
|
||
PatKind::Paren(fields.into_iter().nth(0).unwrap())
|
||
} else {
|
||
PatKind::Tuple(fields, ddpos)
|
||
};
|
||
}
|
||
token::OpenDelim(token::Bracket) => {
|
||
// Parse [pat,pat,...] as slice pattern
|
||
self.bump();
|
||
let (before, slice, after) = self.parse_pat_vec_elements()?;
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
pat = PatKind::Slice(before, slice, after);
|
||
}
|
||
// At this point, token != &, &&, (, [
|
||
_ => if self.eat_keyword(keywords::Underscore) {
|
||
// Parse _
|
||
pat = PatKind::Wild;
|
||
} else if self.eat_keyword(keywords::Mut) {
|
||
// Parse mut ident @ pat / mut ref ident @ pat
|
||
let mutref_span = self.prev_span.to(self.span);
|
||
let binding_mode = if self.eat_keyword(keywords::Ref) {
|
||
self.diagnostic()
|
||
.struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect")
|
||
.span_suggestion(
|
||
mutref_span,
|
||
"try switching the order",
|
||
"ref mut".into(),
|
||
Applicability::MachineApplicable
|
||
).emit();
|
||
BindingMode::ByRef(Mutability::Mutable)
|
||
} else {
|
||
BindingMode::ByValue(Mutability::Mutable)
|
||
};
|
||
pat = self.parse_pat_ident(binding_mode)?;
|
||
} else if self.eat_keyword(keywords::Ref) {
|
||
// Parse ref ident @ pat / ref mut ident @ pat
|
||
let mutbl = self.parse_mutability();
|
||
pat = self.parse_pat_ident(BindingMode::ByRef(mutbl))?;
|
||
} else if self.eat_keyword(keywords::Box) {
|
||
// Parse box pat
|
||
let subpat = self.parse_pat_with_range_pat(false, None)?;
|
||
pat = PatKind::Box(subpat);
|
||
} else if self.token.is_ident() && !self.token.is_reserved_ident() &&
|
||
self.parse_as_ident() {
|
||
// Parse ident @ pat
|
||
// This can give false positives and parse nullary enums,
|
||
// they are dealt with later in resolve
|
||
let binding_mode = BindingMode::ByValue(Mutability::Immutable);
|
||
pat = self.parse_pat_ident(binding_mode)?;
|
||
} else if self.token.is_path_start() {
|
||
// Parse pattern starting with a path
|
||
let (qself, path) = if self.eat_lt() {
|
||
// Parse a qualified path
|
||
let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
|
||
(Some(qself), path)
|
||
} else {
|
||
// Parse an unqualified path
|
||
(None, self.parse_path(PathStyle::Expr)?)
|
||
};
|
||
match self.token {
|
||
token::Not if qself.is_none() => {
|
||
// Parse macro invocation
|
||
self.bump();
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
let mac = respan(lo.to(self.prev_span), Mac_ { path, tts, delim });
|
||
pat = PatKind::Mac(mac);
|
||
}
|
||
token::DotDotDot | token::DotDotEq | token::DotDot => {
|
||
let end_kind = match self.token {
|
||
token::DotDot => RangeEnd::Excluded,
|
||
token::DotDotDot => RangeEnd::Included(RangeSyntax::DotDotDot),
|
||
token::DotDotEq => RangeEnd::Included(RangeSyntax::DotDotEq),
|
||
_ => panic!("can only parse `..`/`...`/`..=` for ranges \
|
||
(checked above)"),
|
||
};
|
||
let op_span = self.span;
|
||
// Parse range
|
||
let span = lo.to(self.prev_span);
|
||
let begin = self.mk_expr(span, ExprKind::Path(qself, path), ThinVec::new());
|
||
self.bump();
|
||
let end = self.parse_pat_range_end()?;
|
||
let op = Spanned { span: op_span, node: end_kind };
|
||
pat = PatKind::Range(begin, end, op);
|
||
}
|
||
token::OpenDelim(token::Brace) => {
|
||
if qself.is_some() {
|
||
let msg = "unexpected `{` after qualified path";
|
||
let mut err = self.fatal(msg);
|
||
err.span_label(self.span, msg);
|
||
return Err(err);
|
||
}
|
||
// Parse struct pattern
|
||
self.bump();
|
||
let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
|
||
e.emit();
|
||
self.recover_stmt();
|
||
(vec![], false)
|
||
});
|
||
self.bump();
|
||
pat = PatKind::Struct(path, fields, etc);
|
||
}
|
||
token::OpenDelim(token::Paren) => {
|
||
if qself.is_some() {
|
||
let msg = "unexpected `(` after qualified path";
|
||
let mut err = self.fatal(msg);
|
||
err.span_label(self.span, msg);
|
||
return Err(err);
|
||
}
|
||
// Parse tuple struct or enum pattern
|
||
let (fields, ddpos, _) = self.parse_parenthesized_pat_list()?;
|
||
pat = PatKind::TupleStruct(path, fields, ddpos)
|
||
}
|
||
_ => pat = PatKind::Path(qself, path),
|
||
}
|
||
} else {
|
||
// Try to parse everything else as literal with optional minus
|
||
match self.parse_literal_maybe_minus() {
|
||
Ok(begin) => {
|
||
let op_span = self.span;
|
||
if self.check(&token::DotDot) || self.check(&token::DotDotEq) ||
|
||
self.check(&token::DotDotDot) {
|
||
let end_kind = if self.eat(&token::DotDotDot) {
|
||
RangeEnd::Included(RangeSyntax::DotDotDot)
|
||
} else if self.eat(&token::DotDotEq) {
|
||
RangeEnd::Included(RangeSyntax::DotDotEq)
|
||
} else if self.eat(&token::DotDot) {
|
||
RangeEnd::Excluded
|
||
} else {
|
||
panic!("impossible case: we already matched \
|
||
on a range-operator token")
|
||
};
|
||
let end = self.parse_pat_range_end()?;
|
||
let op = Spanned { span: op_span, node: end_kind };
|
||
pat = PatKind::Range(begin, end, op);
|
||
} else {
|
||
pat = PatKind::Lit(begin);
|
||
}
|
||
}
|
||
Err(mut err) => {
|
||
self.cancel(&mut err);
|
||
let expected = expected.unwrap_or("pattern");
|
||
let msg = format!(
|
||
"expected {}, found {}",
|
||
expected,
|
||
self.this_token_descr(),
|
||
);
|
||
let mut err = self.fatal(&msg);
|
||
err.span_label(self.span, format!("expected {}", expected));
|
||
return Err(err);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
let pat = Pat { node: pat, span: lo.to(self.prev_span), id: ast::DUMMY_NODE_ID };
|
||
let pat = self.maybe_recover_from_bad_qpath(pat, true)?;
|
||
|
||
if !allow_range_pat {
|
||
match pat.node {
|
||
PatKind::Range(
|
||
_, _, Spanned { node: RangeEnd::Included(RangeSyntax::DotDotDot), .. }
|
||
) => {},
|
||
PatKind::Range(..) => {
|
||
let mut err = self.struct_span_err(
|
||
pat.span,
|
||
"the range pattern here has ambiguous interpretation",
|
||
);
|
||
err.span_suggestion(
|
||
pat.span,
|
||
"add parentheses to clarify the precedence",
|
||
format!("({})", pprust::pat_to_string(&pat)),
|
||
// "ambiguous interpretation" implies that we have to be guessing
|
||
Applicability::MaybeIncorrect
|
||
);
|
||
return Err(err);
|
||
}
|
||
_ => {}
|
||
}
|
||
}
|
||
|
||
Ok(P(pat))
|
||
}
|
||
|
||
/// Parses `ident` or `ident @ pat`.
|
||
/// used by the copy foo and ref foo patterns to give a good
|
||
/// error message when parsing mistakes like `ref foo(a, b)`.
|
||
fn parse_pat_ident(&mut self,
|
||
binding_mode: ast::BindingMode)
|
||
-> PResult<'a, PatKind> {
|
||
let ident = self.parse_ident()?;
|
||
let sub = if self.eat(&token::At) {
|
||
Some(self.parse_pat(Some("binding pattern"))?)
|
||
} else {
|
||
None
|
||
};
|
||
|
||
// just to be friendly, if they write something like
|
||
// ref Some(i)
|
||
// we end up here with ( as the current token. This shortly
|
||
// leads to a parse error. Note that if there is no explicit
|
||
// binding mode then we do not end up here, because the lookahead
|
||
// will direct us over to parse_enum_variant()
|
||
if self.token == token::OpenDelim(token::Paren) {
|
||
return Err(self.span_fatal(
|
||
self.prev_span,
|
||
"expected identifier, found enum pattern"))
|
||
}
|
||
|
||
Ok(PatKind::Ident(binding_mode, ident, sub))
|
||
}
|
||
|
||
/// Parses a local variable declaration.
|
||
fn parse_local(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Local>> {
|
||
let lo = self.prev_span;
|
||
let pat = self.parse_top_level_pat()?;
|
||
|
||
let (err, ty) = if self.eat(&token::Colon) {
|
||
// Save the state of the parser before parsing type normally, in case there is a `:`
|
||
// instead of an `=` typo.
|
||
let parser_snapshot_before_type = self.clone();
|
||
let colon_sp = self.prev_span;
|
||
match self.parse_ty() {
|
||
Ok(ty) => (None, Some(ty)),
|
||
Err(mut err) => {
|
||
// Rewind to before attempting to parse the type and continue parsing
|
||
let parser_snapshot_after_type = self.clone();
|
||
mem::replace(self, parser_snapshot_before_type);
|
||
|
||
let snippet = self.sess.source_map().span_to_snippet(pat.span).unwrap();
|
||
err.span_label(pat.span, format!("while parsing the type for `{}`", snippet));
|
||
(Some((parser_snapshot_after_type, colon_sp, err)), None)
|
||
}
|
||
}
|
||
} else {
|
||
(None, None)
|
||
};
|
||
let init = match (self.parse_initializer(err.is_some()), err) {
|
||
(Ok(init), None) => { // init parsed, ty parsed
|
||
init
|
||
}
|
||
(Ok(init), Some((_, colon_sp, mut err))) => { // init parsed, ty error
|
||
// Could parse the type as if it were the initializer, it is likely there was a
|
||
// typo in the code: `:` instead of `=`. Add suggestion and emit the error.
|
||
err.span_suggestion_short(
|
||
colon_sp,
|
||
"use `=` if you meant to assign",
|
||
"=".to_string(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
err.emit();
|
||
// As this was parsed successfully, continue as if the code has been fixed for the
|
||
// rest of the file. It will still fail due to the emitted error, but we avoid
|
||
// extra noise.
|
||
init
|
||
}
|
||
(Err(mut init_err), Some((snapshot, _, ty_err))) => { // init error, ty error
|
||
init_err.cancel();
|
||
// Couldn't parse the type nor the initializer, only raise the type error and
|
||
// return to the parser state before parsing the type as the initializer.
|
||
// let x: <parse_error>;
|
||
mem::replace(self, snapshot);
|
||
return Err(ty_err);
|
||
}
|
||
(Err(err), None) => { // init error, ty parsed
|
||
// Couldn't parse the initializer and we're not attempting to recover a failed
|
||
// parse of the type, return the error.
|
||
return Err(err);
|
||
}
|
||
};
|
||
let hi = if self.token == token::Semi {
|
||
self.span
|
||
} else {
|
||
self.prev_span
|
||
};
|
||
Ok(P(ast::Local {
|
||
ty,
|
||
pat,
|
||
init,
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
attrs,
|
||
}))
|
||
}
|
||
|
||
/// Parses a structure field.
|
||
fn parse_name_and_ty(&mut self,
|
||
lo: Span,
|
||
vis: Visibility,
|
||
attrs: Vec<Attribute>)
|
||
-> PResult<'a, StructField> {
|
||
let name = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
Ok(StructField {
|
||
span: lo.to(self.prev_span),
|
||
ident: Some(name),
|
||
vis,
|
||
id: ast::DUMMY_NODE_ID,
|
||
ty,
|
||
attrs,
|
||
})
|
||
}
|
||
|
||
/// Emits an expected-item-after-attributes error.
|
||
fn expected_item_err(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> {
|
||
let message = match attrs.last() {
|
||
Some(&Attribute { is_sugared_doc: true, .. }) => "expected item after doc comment",
|
||
_ => "expected item after attributes",
|
||
};
|
||
|
||
let mut err = self.diagnostic().struct_span_err(self.prev_span, message);
|
||
if attrs.last().unwrap().is_sugared_doc {
|
||
err.span_label(self.prev_span, "this doc comment doesn't document anything");
|
||
}
|
||
Err(err)
|
||
}
|
||
|
||
/// Parse a statement. This stops just before trailing semicolons on everything but items.
|
||
/// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
|
||
pub fn parse_stmt(&mut self) -> PResult<'a, Option<Stmt>> {
|
||
Ok(self.parse_stmt_(true))
|
||
}
|
||
|
||
// Eat tokens until we can be relatively sure we reached the end of the
|
||
// statement. This is something of a best-effort heuristic.
|
||
//
|
||
// We terminate when we find an unmatched `}` (without consuming it).
|
||
fn recover_stmt(&mut self) {
|
||
self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore)
|
||
}
|
||
|
||
// If `break_on_semi` is `Break`, then we will stop consuming tokens after
|
||
// finding (and consuming) a `;` outside of `{}` or `[]` (note that this is
|
||
// approximate - it can mean we break too early due to macros, but that
|
||
// should only lead to sub-optimal recovery, not inaccurate parsing).
|
||
//
|
||
// If `break_on_block` is `Break`, then we will stop consuming tokens
|
||
// after finding (and consuming) a brace-delimited block.
|
||
fn recover_stmt_(&mut self, break_on_semi: SemiColonMode, break_on_block: BlockMode) {
|
||
let mut brace_depth = 0;
|
||
let mut bracket_depth = 0;
|
||
let mut in_block = false;
|
||
debug!("recover_stmt_ enter loop (semi={:?}, block={:?})",
|
||
break_on_semi, break_on_block);
|
||
loop {
|
||
debug!("recover_stmt_ loop {:?}", self.token);
|
||
match self.token {
|
||
token::OpenDelim(token::DelimToken::Brace) => {
|
||
brace_depth += 1;
|
||
self.bump();
|
||
if break_on_block == BlockMode::Break &&
|
||
brace_depth == 1 &&
|
||
bracket_depth == 0 {
|
||
in_block = true;
|
||
}
|
||
}
|
||
token::OpenDelim(token::DelimToken::Bracket) => {
|
||
bracket_depth += 1;
|
||
self.bump();
|
||
}
|
||
token::CloseDelim(token::DelimToken::Brace) => {
|
||
if brace_depth == 0 {
|
||
debug!("recover_stmt_ return - close delim {:?}", self.token);
|
||
break;
|
||
}
|
||
brace_depth -= 1;
|
||
self.bump();
|
||
if in_block && bracket_depth == 0 && brace_depth == 0 {
|
||
debug!("recover_stmt_ return - block end {:?}", self.token);
|
||
break;
|
||
}
|
||
}
|
||
token::CloseDelim(token::DelimToken::Bracket) => {
|
||
bracket_depth -= 1;
|
||
if bracket_depth < 0 {
|
||
bracket_depth = 0;
|
||
}
|
||
self.bump();
|
||
}
|
||
token::Eof => {
|
||
debug!("recover_stmt_ return - Eof");
|
||
break;
|
||
}
|
||
token::Semi => {
|
||
self.bump();
|
||
if break_on_semi == SemiColonMode::Break &&
|
||
brace_depth == 0 &&
|
||
bracket_depth == 0 {
|
||
debug!("recover_stmt_ return - Semi");
|
||
break;
|
||
}
|
||
}
|
||
token::Comma => {
|
||
if break_on_semi == SemiColonMode::Comma &&
|
||
brace_depth == 0 &&
|
||
bracket_depth == 0 {
|
||
debug!("recover_stmt_ return - Semi");
|
||
break;
|
||
} else {
|
||
self.bump();
|
||
}
|
||
}
|
||
_ => {
|
||
self.bump()
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
fn parse_stmt_(&mut self, macro_legacy_warnings: bool) -> Option<Stmt> {
|
||
self.parse_stmt_without_recovery(macro_legacy_warnings).unwrap_or_else(|mut e| {
|
||
e.emit();
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
|
||
None
|
||
})
|
||
}
|
||
|
||
fn is_async_block(&mut self) -> bool {
|
||
self.token.is_keyword(keywords::Async) &&
|
||
(
|
||
( // `async move {`
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Move)) &&
|
||
self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))
|
||
) || ( // `async {`
|
||
self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace))
|
||
)
|
||
)
|
||
}
|
||
|
||
fn is_do_catch_block(&mut self) -> bool {
|
||
self.token.is_keyword(keywords::Do) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Catch)) &&
|
||
self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace)) &&
|
||
!self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
|
||
}
|
||
|
||
fn is_try_block(&mut self) -> bool {
|
||
self.token.is_keyword(keywords::Try) &&
|
||
self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) &&
|
||
self.span.rust_2018() &&
|
||
// prevent `while try {} {}`, `if try {} {} else {}`, etc.
|
||
!self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
|
||
}
|
||
|
||
fn is_union_item(&self) -> bool {
|
||
self.token.is_keyword(keywords::Union) &&
|
||
self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
|
||
}
|
||
|
||
fn is_crate_vis(&self) -> bool {
|
||
self.token.is_keyword(keywords::Crate) && self.look_ahead(1, |t| t != &token::ModSep)
|
||
}
|
||
|
||
fn is_existential_type_decl(&self) -> bool {
|
||
self.token.is_keyword(keywords::Existential) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Type))
|
||
}
|
||
|
||
fn is_auto_trait_item(&mut self) -> bool {
|
||
// auto trait
|
||
(self.token.is_keyword(keywords::Auto)
|
||
&& self.look_ahead(1, |t| t.is_keyword(keywords::Trait)))
|
||
|| // unsafe auto trait
|
||
(self.token.is_keyword(keywords::Unsafe) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Auto)) &&
|
||
self.look_ahead(2, |t| t.is_keyword(keywords::Trait)))
|
||
}
|
||
|
||
fn eat_macro_def(&mut self, attrs: &[Attribute], vis: &Visibility, lo: Span)
|
||
-> PResult<'a, Option<P<Item>>> {
|
||
let token_lo = self.span;
|
||
let (ident, def) = match self.token {
|
||
token::Ident(ident, false) if ident.name == keywords::Macro.name() => {
|
||
self.bump();
|
||
let ident = self.parse_ident()?;
|
||
let tokens = if self.check(&token::OpenDelim(token::Brace)) {
|
||
match self.parse_token_tree() {
|
||
TokenTree::Delimited(_, _, tts) => tts,
|
||
_ => unreachable!(),
|
||
}
|
||
} else if self.check(&token::OpenDelim(token::Paren)) {
|
||
let args = self.parse_token_tree();
|
||
let body = if self.check(&token::OpenDelim(token::Brace)) {
|
||
self.parse_token_tree()
|
||
} else {
|
||
self.unexpected()?;
|
||
unreachable!()
|
||
};
|
||
TokenStream::new(vec![
|
||
args.into(),
|
||
TokenTree::Token(token_lo.to(self.prev_span), token::FatArrow).into(),
|
||
body.into(),
|
||
])
|
||
} else {
|
||
self.unexpected()?;
|
||
unreachable!()
|
||
};
|
||
|
||
(ident, ast::MacroDef { tokens: tokens.into(), legacy: false })
|
||
}
|
||
token::Ident(ident, _) if ident.name == "macro_rules" &&
|
||
self.look_ahead(1, |t| *t == token::Not) => {
|
||
let prev_span = self.prev_span;
|
||
self.complain_if_pub_macro(&vis.node, prev_span);
|
||
self.bump();
|
||
self.bump();
|
||
|
||
let ident = self.parse_ident()?;
|
||
let (delim, tokens) = self.expect_delimited_token_tree()?;
|
||
if delim != MacDelimiter::Brace {
|
||
if !self.eat(&token::Semi) {
|
||
let msg = "macros that expand to items must either \
|
||
be surrounded with braces or followed by a semicolon";
|
||
self.span_err(self.prev_span, msg);
|
||
}
|
||
}
|
||
|
||
(ident, ast::MacroDef { tokens: tokens, legacy: true })
|
||
}
|
||
_ => return Ok(None),
|
||
};
|
||
|
||
let span = lo.to(self.prev_span);
|
||
Ok(Some(self.mk_item(span, ident, ItemKind::MacroDef(def), vis.clone(), attrs.to_vec())))
|
||
}
|
||
|
||
fn parse_stmt_without_recovery(&mut self,
|
||
macro_legacy_warnings: bool)
|
||
-> PResult<'a, Option<Stmt>> {
|
||
maybe_whole!(self, NtStmt, |x| Some(x));
|
||
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
|
||
Ok(Some(if self.eat_keyword(keywords::Let) {
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: StmtKind::Local(self.parse_local(attrs.into())?),
|
||
span: lo.to(self.prev_span),
|
||
}
|
||
} else if let Some(macro_def) = self.eat_macro_def(
|
||
&attrs,
|
||
&source_map::respan(lo, VisibilityKind::Inherited),
|
||
lo,
|
||
)? {
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: StmtKind::Item(macro_def),
|
||
span: lo.to(self.prev_span),
|
||
}
|
||
// Starts like a simple path, being careful to avoid contextual keywords
|
||
// such as a union items, item with `crate` visibility or auto trait items.
|
||
// Our goal here is to parse an arbitrary path `a::b::c` but not something that starts
|
||
// like a path (1 token), but it fact not a path.
|
||
// `union::b::c` - path, `union U { ... }` - not a path.
|
||
// `crate::b::c` - path, `crate struct S;` - not a path.
|
||
} else if self.token.is_path_start() &&
|
||
!self.token.is_qpath_start() &&
|
||
!self.is_union_item() &&
|
||
!self.is_crate_vis() &&
|
||
!self.is_existential_type_decl() &&
|
||
!self.is_auto_trait_item() {
|
||
let pth = self.parse_path(PathStyle::Expr)?;
|
||
|
||
if !self.eat(&token::Not) {
|
||
let expr = if self.check(&token::OpenDelim(token::Brace)) {
|
||
self.parse_struct_expr(lo, pth, ThinVec::new())?
|
||
} else {
|
||
let hi = self.prev_span;
|
||
self.mk_expr(lo.to(hi), ExprKind::Path(None, pth), ThinVec::new())
|
||
};
|
||
|
||
let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
|
||
let expr = this.parse_dot_or_call_expr_with(expr, lo, attrs.into())?;
|
||
this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
|
||
})?;
|
||
|
||
return Ok(Some(Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: StmtKind::Expr(expr),
|
||
span: lo.to(self.prev_span),
|
||
}));
|
||
}
|
||
|
||
// it's a macro invocation
|
||
let id = match self.token {
|
||
token::OpenDelim(_) => keywords::Invalid.ident(), // no special identifier
|
||
_ => self.parse_ident()?,
|
||
};
|
||
|
||
// check that we're pointing at delimiters (need to check
|
||
// again after the `if`, because of `parse_ident`
|
||
// consuming more tokens).
|
||
match self.token {
|
||
token::OpenDelim(_) => {}
|
||
_ => {
|
||
// we only expect an ident if we didn't parse one
|
||
// above.
|
||
let ident_str = if id.name == keywords::Invalid.name() {
|
||
"identifier, "
|
||
} else {
|
||
""
|
||
};
|
||
let tok_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!("expected {}`(` or `{{`, found {}",
|
||
ident_str,
|
||
tok_str));
|
||
err.span_label(self.span, format!("expected {}`(` or `{{`", ident_str));
|
||
return Err(err)
|
||
},
|
||
}
|
||
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
let hi = self.prev_span;
|
||
|
||
let style = if delim == MacDelimiter::Brace {
|
||
MacStmtStyle::Braces
|
||
} else {
|
||
MacStmtStyle::NoBraces
|
||
};
|
||
|
||
if id.name == keywords::Invalid.name() {
|
||
let mac = respan(lo.to(hi), Mac_ { path: pth, tts, delim });
|
||
let node = if delim == MacDelimiter::Brace ||
|
||
self.token == token::Semi || self.token == token::Eof {
|
||
StmtKind::Mac(P((mac, style, attrs.into())))
|
||
}
|
||
// We used to incorrectly stop parsing macro-expanded statements here.
|
||
// If the next token will be an error anyway but could have parsed with the
|
||
// earlier behavior, stop parsing here and emit a warning to avoid breakage.
|
||
else if macro_legacy_warnings && self.token.can_begin_expr() && match self.token {
|
||
// These can continue an expression, so we can't stop parsing and warn.
|
||
token::OpenDelim(token::Paren) | token::OpenDelim(token::Bracket) |
|
||
token::BinOp(token::Minus) | token::BinOp(token::Star) |
|
||
token::BinOp(token::And) | token::BinOp(token::Or) |
|
||
token::AndAnd | token::OrOr |
|
||
token::DotDot | token::DotDotDot | token::DotDotEq => false,
|
||
_ => true,
|
||
} {
|
||
self.warn_missing_semicolon();
|
||
StmtKind::Mac(P((mac, style, attrs.into())))
|
||
} else {
|
||
let e = self.mk_mac_expr(lo.to(hi), mac.node, ThinVec::new());
|
||
let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
|
||
let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
|
||
StmtKind::Expr(e)
|
||
};
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
node,
|
||
}
|
||
} else {
|
||
// if it has a special ident, it's definitely an item
|
||
//
|
||
// Require a semicolon or braces.
|
||
if style != MacStmtStyle::Braces {
|
||
if !self.eat(&token::Semi) {
|
||
self.span_err(self.prev_span,
|
||
"macros that expand to items must \
|
||
either be surrounded with braces or \
|
||
followed by a semicolon");
|
||
}
|
||
}
|
||
let span = lo.to(hi);
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span,
|
||
node: StmtKind::Item({
|
||
self.mk_item(
|
||
span, id /*id is good here*/,
|
||
ItemKind::Mac(respan(span, Mac_ { path: pth, tts, delim })),
|
||
respan(lo, VisibilityKind::Inherited),
|
||
attrs)
|
||
}),
|
||
}
|
||
}
|
||
} else {
|
||
// FIXME: Bad copy of attrs
|
||
let old_directory_ownership =
|
||
mem::replace(&mut self.directory.ownership, DirectoryOwnership::UnownedViaBlock);
|
||
let item = self.parse_item_(attrs.clone(), false, true)?;
|
||
self.directory.ownership = old_directory_ownership;
|
||
|
||
match item {
|
||
Some(i) => Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(i.span),
|
||
node: StmtKind::Item(i),
|
||
},
|
||
None => {
|
||
let unused_attrs = |attrs: &[Attribute], s: &mut Self| {
|
||
if !attrs.is_empty() {
|
||
if s.prev_token_kind == PrevTokenKind::DocComment {
|
||
s.span_fatal_err(s.prev_span, Error::UselessDocComment).emit();
|
||
} else if attrs.iter().any(|a| a.style == AttrStyle::Outer) {
|
||
s.span_err(s.span, "expected statement after outer attribute");
|
||
}
|
||
}
|
||
};
|
||
|
||
// Do not attempt to parse an expression if we're done here.
|
||
if self.token == token::Semi {
|
||
unused_attrs(&attrs, self);
|
||
self.bump();
|
||
return Ok(None);
|
||
}
|
||
|
||
if self.token == token::CloseDelim(token::Brace) {
|
||
unused_attrs(&attrs, self);
|
||
return Ok(None);
|
||
}
|
||
|
||
// Remainder are line-expr stmts.
|
||
let e = self.parse_expr_res(
|
||
Restrictions::STMT_EXPR, Some(attrs.into()))?;
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(e.span),
|
||
node: StmtKind::Expr(e),
|
||
}
|
||
}
|
||
}
|
||
}))
|
||
}
|
||
|
||
/// Checks if this expression is a successfully parsed statement.
|
||
fn expr_is_complete(&mut self, e: &Expr) -> bool {
|
||
self.restrictions.contains(Restrictions::STMT_EXPR) &&
|
||
!classify::expr_requires_semi_to_be_stmt(e)
|
||
}
|
||
|
||
/// Parses a block. No inner attributes are allowed.
|
||
pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
|
||
maybe_whole!(self, NtBlock, |x| x);
|
||
|
||
let lo = self.span;
|
||
|
||
if !self.eat(&token::OpenDelim(token::Brace)) {
|
||
let sp = self.span;
|
||
let tok = self.this_token_descr();
|
||
let mut e = self.span_fatal(sp, &format!("expected `{{`, found {}", tok));
|
||
let do_not_suggest_help =
|
||
self.token.is_keyword(keywords::In) || self.token == token::Colon;
|
||
|
||
if self.token.is_ident_named("and") {
|
||
e.span_suggestion_short(
|
||
self.span,
|
||
"use `&&` instead of `and` for the boolean operator",
|
||
"&&".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
if self.token.is_ident_named("or") {
|
||
e.span_suggestion_short(
|
||
self.span,
|
||
"use `||` instead of `or` for the boolean operator",
|
||
"||".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
|
||
// Check to see if the user has written something like
|
||
//
|
||
// if (cond)
|
||
// bar;
|
||
//
|
||
// Which is valid in other languages, but not Rust.
|
||
match self.parse_stmt_without_recovery(false) {
|
||
Ok(Some(stmt)) => {
|
||
if self.look_ahead(1, |t| t == &token::OpenDelim(token::Brace))
|
||
|| do_not_suggest_help {
|
||
// if the next token is an open brace (e.g., `if a b {`), the place-
|
||
// inside-a-block suggestion would be more likely wrong than right
|
||
e.span_label(sp, "expected `{`");
|
||
return Err(e);
|
||
}
|
||
let mut stmt_span = stmt.span;
|
||
// expand the span to include the semicolon, if it exists
|
||
if self.eat(&token::Semi) {
|
||
stmt_span = stmt_span.with_hi(self.prev_span.hi());
|
||
}
|
||
let sugg = pprust::to_string(|s| {
|
||
use crate::print::pprust::{PrintState, INDENT_UNIT};
|
||
s.ibox(INDENT_UNIT)?;
|
||
s.bopen()?;
|
||
s.print_stmt(&stmt)?;
|
||
s.bclose_maybe_open(stmt.span, INDENT_UNIT, false)
|
||
});
|
||
e.span_suggestion(
|
||
stmt_span,
|
||
"try placing this code inside a block",
|
||
sugg,
|
||
// speculative, has been misleading in the past (closed Issue #46836)
|
||
Applicability::MaybeIncorrect
|
||
);
|
||
}
|
||
Err(mut e) => {
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
|
||
self.cancel(&mut e);
|
||
}
|
||
_ => ()
|
||
}
|
||
e.span_label(sp, "expected `{`");
|
||
return Err(e);
|
||
}
|
||
|
||
self.parse_block_tail(lo, BlockCheckMode::Default)
|
||
}
|
||
|
||
/// Parses a block. Inner attributes are allowed.
|
||
fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
|
||
maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
|
||
|
||
let lo = self.span;
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
Ok((self.parse_inner_attributes()?,
|
||
self.parse_block_tail(lo, BlockCheckMode::Default)?))
|
||
}
|
||
|
||
/// Parses the rest of a block expression or function body.
|
||
/// Precondition: already parsed the '{'.
|
||
fn parse_block_tail(&mut self, lo: Span, s: BlockCheckMode) -> PResult<'a, P<Block>> {
|
||
let mut stmts = vec![];
|
||
while !self.eat(&token::CloseDelim(token::Brace)) {
|
||
let stmt = match self.parse_full_stmt(false) {
|
||
Err(mut err) => {
|
||
err.emit();
|
||
self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
|
||
Some(Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: StmtKind::Expr(DummyResult::raw_expr(self.span, true)),
|
||
span: self.span,
|
||
})
|
||
}
|
||
Ok(stmt) => stmt,
|
||
};
|
||
if let Some(stmt) = stmt {
|
||
stmts.push(stmt);
|
||
} else if self.token == token::Eof {
|
||
break;
|
||
} else {
|
||
// Found only `;` or `}`.
|
||
continue;
|
||
};
|
||
}
|
||
Ok(P(ast::Block {
|
||
stmts,
|
||
id: ast::DUMMY_NODE_ID,
|
||
rules: s,
|
||
span: lo.to(self.prev_span),
|
||
}))
|
||
}
|
||
|
||
/// Parses a statement, including the trailing semicolon.
|
||
crate fn parse_full_stmt(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option<Stmt>> {
|
||
// skip looking for a trailing semicolon when we have an interpolated statement
|
||
maybe_whole!(self, NtStmt, |x| Some(x));
|
||
|
||
let mut stmt = match self.parse_stmt_without_recovery(macro_legacy_warnings)? {
|
||
Some(stmt) => stmt,
|
||
None => return Ok(None),
|
||
};
|
||
|
||
match stmt.node {
|
||
StmtKind::Expr(ref expr) if self.token != token::Eof => {
|
||
// expression without semicolon
|
||
if classify::expr_requires_semi_to_be_stmt(expr) {
|
||
// Just check for errors and recover; do not eat semicolon yet.
|
||
if let Err(mut e) =
|
||
self.expect_one_of(&[], &[token::Semi, token::CloseDelim(token::Brace)])
|
||
{
|
||
e.emit();
|
||
self.recover_stmt();
|
||
}
|
||
}
|
||
}
|
||
StmtKind::Local(..) => {
|
||
// We used to incorrectly allow a macro-expanded let statement to lack a semicolon.
|
||
if macro_legacy_warnings && self.token != token::Semi {
|
||
self.warn_missing_semicolon();
|
||
} else {
|
||
self.expect_one_of(&[], &[token::Semi])?;
|
||
}
|
||
}
|
||
_ => {}
|
||
}
|
||
|
||
if self.eat(&token::Semi) {
|
||
stmt = stmt.add_trailing_semicolon();
|
||
}
|
||
|
||
stmt.span = stmt.span.with_hi(self.prev_span.hi());
|
||
Ok(Some(stmt))
|
||
}
|
||
|
||
fn warn_missing_semicolon(&self) {
|
||
self.diagnostic().struct_span_warn(self.span, {
|
||
&format!("expected `;`, found {}", self.this_token_descr())
|
||
}).note({
|
||
"This was erroneously allowed and will become a hard error in a future release"
|
||
}).emit();
|
||
}
|
||
|
||
fn err_dotdotdot_syntax(&self, span: Span) {
|
||
self.diagnostic().struct_span_err(span, {
|
||
"unexpected token: `...`"
|
||
}).span_suggestion(
|
||
span, "use `..` for an exclusive range", "..".to_owned(),
|
||
Applicability::MaybeIncorrect
|
||
).span_suggestion(
|
||
span, "or `..=` for an inclusive range", "..=".to_owned(),
|
||
Applicability::MaybeIncorrect
|
||
).emit();
|
||
}
|
||
|
||
/// Parses bounds of a type parameter `BOUND + BOUND + ...`, possibly with trailing `+`.
|
||
///
|
||
/// ```
|
||
/// BOUND = TY_BOUND | LT_BOUND
|
||
/// LT_BOUND = LIFETIME (e.g., `'a`)
|
||
/// TY_BOUND = TY_BOUND_NOPAREN | (TY_BOUND_NOPAREN)
|
||
/// TY_BOUND_NOPAREN = [?] [for<LT_PARAM_DEFS>] SIMPLE_PATH (e.g., `?for<'a: 'b> m::Trait<'a>`)
|
||
/// ```
|
||
fn parse_generic_bounds_common(&mut self,
|
||
allow_plus: bool,
|
||
colon_span: Option<Span>) -> PResult<'a, GenericBounds> {
|
||
let mut bounds = Vec::new();
|
||
let mut negative_bounds = Vec::new();
|
||
let mut last_plus_span = None;
|
||
loop {
|
||
// This needs to be synchronized with `Token::can_begin_bound`.
|
||
let is_bound_start = self.check_path() || self.check_lifetime() ||
|
||
self.check(&token::Not) || // used for error reporting only
|
||
self.check(&token::Question) ||
|
||
self.check_keyword(keywords::For) ||
|
||
self.check(&token::OpenDelim(token::Paren));
|
||
if is_bound_start {
|
||
let lo = self.span;
|
||
let has_parens = self.eat(&token::OpenDelim(token::Paren));
|
||
let inner_lo = self.span;
|
||
let is_negative = self.eat(&token::Not);
|
||
let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None };
|
||
if self.token.is_lifetime() {
|
||
if let Some(question_span) = question {
|
||
self.span_err(question_span,
|
||
"`?` may only modify trait bounds, not lifetime bounds");
|
||
}
|
||
bounds.push(GenericBound::Outlives(self.expect_lifetime()));
|
||
if has_parens {
|
||
let inner_span = inner_lo.to(self.prev_span);
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
let mut err = self.struct_span_err(
|
||
lo.to(self.prev_span),
|
||
"parenthesized lifetime bounds are not supported"
|
||
);
|
||
if let Ok(snippet) = self.sess.source_map().span_to_snippet(inner_span) {
|
||
err.span_suggestion_short(
|
||
lo.to(self.prev_span),
|
||
"remove the parentheses",
|
||
snippet.to_owned(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
}
|
||
err.emit();
|
||
}
|
||
} else {
|
||
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
||
let path = self.parse_path(PathStyle::Type)?;
|
||
if has_parens {
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
}
|
||
let poly_span = lo.to(self.prev_span);
|
||
if is_negative {
|
||
negative_bounds.push(
|
||
last_plus_span.or(colon_span).unwrap()
|
||
.to(poly_span));
|
||
} else {
|
||
let poly_trait = PolyTraitRef::new(lifetime_defs, path, poly_span);
|
||
let modifier = if question.is_some() {
|
||
TraitBoundModifier::Maybe
|
||
} else {
|
||
TraitBoundModifier::None
|
||
};
|
||
bounds.push(GenericBound::Trait(poly_trait, modifier));
|
||
}
|
||
}
|
||
} else {
|
||
break
|
||
}
|
||
|
||
if !allow_plus || !self.eat_plus() {
|
||
break
|
||
} else {
|
||
last_plus_span = Some(self.prev_span);
|
||
}
|
||
}
|
||
|
||
if !negative_bounds.is_empty() {
|
||
let plural = negative_bounds.len() > 1;
|
||
let mut err = self.struct_span_err(negative_bounds,
|
||
"negative trait bounds are not supported");
|
||
let bound_list = colon_span.unwrap().to(self.prev_span);
|
||
let mut new_bound_list = String::new();
|
||
if !bounds.is_empty() {
|
||
let mut snippets = bounds.iter().map(|bound| bound.span())
|
||
.map(|span| self.sess.source_map().span_to_snippet(span));
|
||
while let Some(Ok(snippet)) = snippets.next() {
|
||
new_bound_list.push_str(" + ");
|
||
new_bound_list.push_str(&snippet);
|
||
}
|
||
new_bound_list = new_bound_list.replacen(" +", ":", 1);
|
||
}
|
||
err.span_suggestion_short(bound_list,
|
||
&format!("remove the trait bound{}",
|
||
if plural { "s" } else { "" }),
|
||
new_bound_list,
|
||
Applicability::MachineApplicable);
|
||
err.emit();
|
||
}
|
||
|
||
return Ok(bounds);
|
||
}
|
||
|
||
fn parse_generic_bounds(&mut self, colon_span: Option<Span>) -> PResult<'a, GenericBounds> {
|
||
self.parse_generic_bounds_common(true, colon_span)
|
||
}
|
||
|
||
/// Parses bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
|
||
///
|
||
/// ```
|
||
/// BOUND = LT_BOUND (e.g., `'a`)
|
||
/// ```
|
||
fn parse_lt_param_bounds(&mut self) -> GenericBounds {
|
||
let mut lifetimes = Vec::new();
|
||
while self.check_lifetime() {
|
||
lifetimes.push(ast::GenericBound::Outlives(self.expect_lifetime()));
|
||
|
||
if !self.eat_plus() {
|
||
break
|
||
}
|
||
}
|
||
lifetimes
|
||
}
|
||
|
||
/// Matches `typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?`.
|
||
fn parse_ty_param(&mut self,
|
||
preceding_attrs: Vec<Attribute>)
|
||
-> PResult<'a, GenericParam> {
|
||
let ident = self.parse_ident()?;
|
||
|
||
// Parse optional colon and param bounds.
|
||
let bounds = if self.eat(&token::Colon) {
|
||
self.parse_generic_bounds(None)?
|
||
} else {
|
||
Vec::new()
|
||
};
|
||
|
||
let default = if self.eat(&token::Eq) {
|
||
Some(self.parse_ty()?)
|
||
} else {
|
||
None
|
||
};
|
||
|
||
Ok(GenericParam {
|
||
ident,
|
||
id: ast::DUMMY_NODE_ID,
|
||
attrs: preceding_attrs.into(),
|
||
bounds,
|
||
kind: GenericParamKind::Type {
|
||
default,
|
||
}
|
||
})
|
||
}
|
||
|
||
/// Parses the following grammar:
|
||
///
|
||
/// TraitItemAssocTy = Ident ["<"...">"] [":" [GenericBounds]] ["where" ...] ["=" Ty]
|
||
fn parse_trait_item_assoc_ty(&mut self)
|
||
-> PResult<'a, (Ident, TraitItemKind, ast::Generics)> {
|
||
let ident = self.parse_ident()?;
|
||
let mut generics = self.parse_generics()?;
|
||
|
||
// Parse optional colon and param bounds.
|
||
let bounds = if self.eat(&token::Colon) {
|
||
self.parse_generic_bounds(None)?
|
||
} else {
|
||
Vec::new()
|
||
};
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
|
||
let default = if self.eat(&token::Eq) {
|
||
Some(self.parse_ty()?)
|
||
} else {
|
||
None
|
||
};
|
||
self.expect(&token::Semi)?;
|
||
|
||
Ok((ident, TraitItemKind::Type(bounds, default), generics))
|
||
}
|
||
|
||
fn parse_const_param(&mut self, preceding_attrs: Vec<Attribute>) -> PResult<'a, GenericParam> {
|
||
self.expect_keyword(keywords::Const)?;
|
||
let ident = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
|
||
Ok(GenericParam {
|
||
ident,
|
||
id: ast::DUMMY_NODE_ID,
|
||
attrs: preceding_attrs.into(),
|
||
bounds: Vec::new(),
|
||
kind: GenericParamKind::Const {
|
||
ty,
|
||
}
|
||
})
|
||
}
|
||
|
||
/// Parses a (possibly empty) list of lifetime and type parameters, possibly including
|
||
/// a trailing comma and erroneous trailing attributes.
|
||
crate fn parse_generic_params(&mut self) -> PResult<'a, Vec<ast::GenericParam>> {
|
||
let mut params = Vec::new();
|
||
loop {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
if self.check_lifetime() {
|
||
let lifetime = self.expect_lifetime();
|
||
// Parse lifetime parameter.
|
||
let bounds = if self.eat(&token::Colon) {
|
||
self.parse_lt_param_bounds()
|
||
} else {
|
||
Vec::new()
|
||
};
|
||
params.push(ast::GenericParam {
|
||
ident: lifetime.ident,
|
||
id: lifetime.id,
|
||
attrs: attrs.into(),
|
||
bounds,
|
||
kind: ast::GenericParamKind::Lifetime,
|
||
});
|
||
} else if self.check_keyword(keywords::Const) {
|
||
// Parse const parameter.
|
||
params.push(self.parse_const_param(attrs)?);
|
||
} else if self.check_ident() {
|
||
// Parse type parameter.
|
||
params.push(self.parse_ty_param(attrs)?);
|
||
} else {
|
||
// Check for trailing attributes and stop parsing.
|
||
if !attrs.is_empty() {
|
||
if !params.is_empty() {
|
||
self.struct_span_err(
|
||
attrs[0].span,
|
||
&format!("trailing attribute after generic parameter"),
|
||
)
|
||
.span_label(attrs[0].span, "attributes must go before parameters")
|
||
.emit();
|
||
} else {
|
||
self.struct_span_err(
|
||
attrs[0].span,
|
||
&format!("attribute without generic parameters"),
|
||
)
|
||
.span_label(
|
||
attrs[0].span,
|
||
"attributes are only permitted when preceding parameters",
|
||
)
|
||
.emit();
|
||
}
|
||
}
|
||
break
|
||
}
|
||
|
||
if !self.eat(&token::Comma) {
|
||
break
|
||
}
|
||
}
|
||
Ok(params)
|
||
}
|
||
|
||
/// Parses a set of optional generic type parameter declarations. Where
|
||
/// clauses are not parsed here, and must be added later via
|
||
/// `parse_where_clause()`.
|
||
///
|
||
/// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
|
||
/// | ( < lifetimes , typaramseq ( , )? > )
|
||
/// where typaramseq = ( typaram ) | ( typaram , typaramseq )
|
||
fn parse_generics(&mut self) -> PResult<'a, ast::Generics> {
|
||
maybe_whole!(self, NtGenerics, |x| x);
|
||
|
||
let span_lo = self.span;
|
||
if self.eat_lt() {
|
||
let params = self.parse_generic_params()?;
|
||
self.expect_gt()?;
|
||
Ok(ast::Generics {
|
||
params,
|
||
where_clause: WhereClause {
|
||
id: ast::DUMMY_NODE_ID,
|
||
predicates: Vec::new(),
|
||
span: syntax_pos::DUMMY_SP,
|
||
},
|
||
span: span_lo.to(self.prev_span),
|
||
})
|
||
} else {
|
||
Ok(ast::Generics::default())
|
||
}
|
||
}
|
||
|
||
/// Parses generic args (within a path segment) with recovery for extra leading angle brackets.
|
||
/// For the purposes of understanding the parsing logic of generic arguments, this function
|
||
/// can be thought of being the same as just calling `self.parse_generic_args()` if the source
|
||
/// had the correct amount of leading angle brackets.
|
||
///
|
||
/// ```ignore (diagnostics)
|
||
/// bar::<<<<T as Foo>::Output>();
|
||
/// ^^ help: remove extra angle brackets
|
||
/// ```
|
||
fn parse_generic_args_with_leaning_angle_bracket_recovery(
|
||
&mut self,
|
||
style: PathStyle,
|
||
lo: Span,
|
||
) -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> {
|
||
// We need to detect whether there are extra leading left angle brackets and produce an
|
||
// appropriate error and suggestion. This cannot be implemented by looking ahead at
|
||
// upcoming tokens for a matching `>` character - if there are unmatched `<` tokens
|
||
// then there won't be matching `>` tokens to find.
|
||
//
|
||
// To explain how this detection works, consider the following example:
|
||
//
|
||
// ```ignore (diagnostics)
|
||
// bar::<<<<T as Foo>::Output>();
|
||
// ^^ help: remove extra angle brackets
|
||
// ```
|
||
//
|
||
// Parsing of the left angle brackets starts in this function. We start by parsing the
|
||
// `<` token (incrementing the counter of unmatched angle brackets on `Parser` via
|
||
// `eat_lt`):
|
||
//
|
||
// *Upcoming tokens:* `<<<<T as Foo>::Output>;`
|
||
// *Unmatched count:* 1
|
||
// *`parse_path_segment` calls deep:* 0
|
||
//
|
||
// This has the effect of recursing as this function is called if a `<` character
|
||
// is found within the expected generic arguments:
|
||
//
|
||
// *Upcoming tokens:* `<<<T as Foo>::Output>;`
|
||
// *Unmatched count:* 2
|
||
// *`parse_path_segment` calls deep:* 1
|
||
//
|
||
// Eventually we will have recursed until having consumed all of the `<` tokens and
|
||
// this will be reflected in the count:
|
||
//
|
||
// *Upcoming tokens:* `T as Foo>::Output>;`
|
||
// *Unmatched count:* 4
|
||
// `parse_path_segment` calls deep:* 3
|
||
//
|
||
// The parser will continue until reaching the first `>` - this will decrement the
|
||
// unmatched angle bracket count and return to the parent invocation of this function
|
||
// having succeeded in parsing:
|
||
//
|
||
// *Upcoming tokens:* `::Output>;`
|
||
// *Unmatched count:* 3
|
||
// *`parse_path_segment` calls deep:* 2
|
||
//
|
||
// This will continue until the next `>` character which will also return successfully
|
||
// to the parent invocation of this function and decrement the count:
|
||
//
|
||
// *Upcoming tokens:* `;`
|
||
// *Unmatched count:* 2
|
||
// *`parse_path_segment` calls deep:* 1
|
||
//
|
||
// At this point, this function will expect to find another matching `>` character but
|
||
// won't be able to and will return an error. This will continue all the way up the
|
||
// call stack until the first invocation:
|
||
//
|
||
// *Upcoming tokens:* `;`
|
||
// *Unmatched count:* 2
|
||
// *`parse_path_segment` calls deep:* 0
|
||
//
|
||
// In doing this, we have managed to work out how many unmatched leading left angle
|
||
// brackets there are, but we cannot recover as the unmatched angle brackets have
|
||
// already been consumed. To remedy this, we keep a snapshot of the parser state
|
||
// before we do the above. We can then inspect whether we ended up with a parsing error
|
||
// and unmatched left angle brackets and if so, restore the parser state before we
|
||
// consumed any `<` characters to emit an error and consume the erroneous tokens to
|
||
// recover by attempting to parse again.
|
||
//
|
||
// In practice, the recursion of this function is indirect and there will be other
|
||
// locations that consume some `<` characters - as long as we update the count when
|
||
// this happens, it isn't an issue.
|
||
|
||
let is_first_invocation = style == PathStyle::Expr;
|
||
// Take a snapshot before attempting to parse - we can restore this later.
|
||
let snapshot = if is_first_invocation {
|
||
Some(self.clone())
|
||
} else {
|
||
None
|
||
};
|
||
|
||
debug!("parse_generic_args_with_leading_angle_bracket_recovery: (snapshotting)");
|
||
match self.parse_generic_args() {
|
||
Ok(value) => Ok(value),
|
||
Err(ref mut e) if is_first_invocation && self.unmatched_angle_bracket_count > 0 => {
|
||
// Cancel error from being unable to find `>`. We know the error
|
||
// must have been this due to a non-zero unmatched angle bracket
|
||
// count.
|
||
e.cancel();
|
||
|
||
// Swap `self` with our backup of the parser state before attempting to parse
|
||
// generic arguments.
|
||
let snapshot = mem::replace(self, snapshot.unwrap());
|
||
|
||
debug!(
|
||
"parse_generic_args_with_leading_angle_bracket_recovery: (snapshot failure) \
|
||
snapshot.count={:?}",
|
||
snapshot.unmatched_angle_bracket_count,
|
||
);
|
||
|
||
// Eat the unmatched angle brackets.
|
||
for _ in 0..snapshot.unmatched_angle_bracket_count {
|
||
self.eat_lt();
|
||
}
|
||
|
||
// Make a span over ${unmatched angle bracket count} characters.
|
||
let span = lo.with_hi(
|
||
lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count)
|
||
);
|
||
let plural = snapshot.unmatched_angle_bracket_count > 1;
|
||
self.diagnostic()
|
||
.struct_span_err(
|
||
span,
|
||
&format!(
|
||
"unmatched angle bracket{}",
|
||
if plural { "s" } else { "" }
|
||
),
|
||
)
|
||
.span_suggestion(
|
||
span,
|
||
&format!(
|
||
"remove extra angle bracket{}",
|
||
if plural { "s" } else { "" }
|
||
),
|
||
String::new(),
|
||
Applicability::MachineApplicable,
|
||
)
|
||
.emit();
|
||
|
||
// Try again without unmatched angle bracket characters.
|
||
self.parse_generic_args()
|
||
},
|
||
Err(e) => Err(e),
|
||
}
|
||
}
|
||
|
||
/// Parses (possibly empty) list of lifetime and type arguments and associated type bindings,
|
||
/// possibly including trailing comma.
|
||
fn parse_generic_args(&mut self) -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> {
|
||
let mut args = Vec::new();
|
||
let mut bindings = Vec::new();
|
||
let mut misplaced_assoc_ty_bindings: Vec<Span> = Vec::new();
|
||
let mut assoc_ty_bindings: Vec<Span> = Vec::new();
|
||
|
||
let args_lo = self.span;
|
||
|
||
loop {
|
||
if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
|
||
// Parse lifetime argument.
|
||
args.push(GenericArg::Lifetime(self.expect_lifetime()));
|
||
misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings);
|
||
} else if self.check_ident() && self.look_ahead(1, |t| t == &token::Eq) {
|
||
// Parse associated type binding.
|
||
let lo = self.span;
|
||
let ident = self.parse_ident()?;
|
||
self.bump();
|
||
let ty = self.parse_ty()?;
|
||
let span = lo.to(self.prev_span);
|
||
bindings.push(TypeBinding {
|
||
id: ast::DUMMY_NODE_ID,
|
||
ident,
|
||
ty,
|
||
span,
|
||
});
|
||
assoc_ty_bindings.push(span);
|
||
} else if self.check_const_arg() {
|
||
// FIXME(const_generics): to distinguish between idents for types and consts,
|
||
// we should introduce a GenericArg::Ident in the AST and distinguish when
|
||
// lowering to the HIR. For now, idents for const args are not permitted.
|
||
|
||
// Parse const argument.
|
||
let expr = if let token::OpenDelim(token::Brace) = self.token {
|
||
self.parse_block_expr(None, self.span, BlockCheckMode::Default, ThinVec::new())?
|
||
} else if self.token.is_ident() {
|
||
// FIXME(const_generics): to distinguish between idents for types and consts,
|
||
// we should introduce a GenericArg::Ident in the AST and distinguish when
|
||
// lowering to the HIR. For now, idents for const args are not permitted.
|
||
return Err(
|
||
self.fatal("identifiers may currently not be used for const generics")
|
||
);
|
||
} else {
|
||
// FIXME(const_generics): this currently conflicts with emplacement syntax
|
||
// with negative integer literals.
|
||
self.parse_literal_maybe_minus()?
|
||
};
|
||
let value = AnonConst {
|
||
id: ast::DUMMY_NODE_ID,
|
||
value: expr,
|
||
};
|
||
args.push(GenericArg::Const(value));
|
||
misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings);
|
||
} else if self.check_type() {
|
||
// Parse type argument.
|
||
args.push(GenericArg::Type(self.parse_ty()?));
|
||
misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings);
|
||
} else {
|
||
break
|
||
}
|
||
|
||
if !self.eat(&token::Comma) {
|
||
break
|
||
}
|
||
}
|
||
|
||
// FIXME: we would like to report this in ast_validation instead, but we currently do not
|
||
// preserve ordering of generic parameters with respect to associated type binding, so we
|
||
// lose that information after parsing.
|
||
if misplaced_assoc_ty_bindings.len() > 0 {
|
||
let mut err = self.struct_span_err(
|
||
args_lo.to(self.prev_span),
|
||
"associated type bindings must be declared after generic parameters",
|
||
);
|
||
for span in misplaced_assoc_ty_bindings {
|
||
err.span_label(
|
||
span,
|
||
"this associated type binding should be moved after the generic parameters",
|
||
);
|
||
}
|
||
err.emit();
|
||
}
|
||
|
||
Ok((args, bindings))
|
||
}
|
||
|
||
/// Parses an optional where-clause and places it in `generics`.
|
||
///
|
||
/// ```ignore (only-for-syntax-highlight)
|
||
/// where T : Trait<U, V> + 'b, 'a : 'b
|
||
/// ```
|
||
fn parse_where_clause(&mut self) -> PResult<'a, WhereClause> {
|
||
maybe_whole!(self, NtWhereClause, |x| x);
|
||
|
||
let mut where_clause = WhereClause {
|
||
id: ast::DUMMY_NODE_ID,
|
||
predicates: Vec::new(),
|
||
span: syntax_pos::DUMMY_SP,
|
||
};
|
||
|
||
if !self.eat_keyword(keywords::Where) {
|
||
return Ok(where_clause);
|
||
}
|
||
let lo = self.prev_span;
|
||
|
||
// We are considering adding generics to the `where` keyword as an alternative higher-rank
|
||
// parameter syntax (as in `where<'a>` or `where<T>`. To avoid that being a breaking
|
||
// change we parse those generics now, but report an error.
|
||
if self.choose_generics_over_qpath() {
|
||
let generics = self.parse_generics()?;
|
||
self.struct_span_err(
|
||
generics.span,
|
||
"generic parameters on `where` clauses are reserved for future use",
|
||
)
|
||
.span_label(generics.span, "currently unsupported")
|
||
.emit();
|
||
}
|
||
|
||
loop {
|
||
let lo = self.span;
|
||
if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
|
||
let lifetime = self.expect_lifetime();
|
||
// Bounds starting with a colon are mandatory, but possibly empty.
|
||
self.expect(&token::Colon)?;
|
||
let bounds = self.parse_lt_param_bounds();
|
||
where_clause.predicates.push(ast::WherePredicate::RegionPredicate(
|
||
ast::WhereRegionPredicate {
|
||
span: lo.to(self.prev_span),
|
||
lifetime,
|
||
bounds,
|
||
}
|
||
));
|
||
} else if self.check_type() {
|
||
// Parse optional `for<'a, 'b>`.
|
||
// This `for` is parsed greedily and applies to the whole predicate,
|
||
// the bounded type can have its own `for` applying only to it.
|
||
// Example 1: for<'a> Trait1<'a>: Trait2<'a /*ok*/>
|
||
// Example 2: (for<'a> Trait1<'a>): Trait2<'a /*not ok*/>
|
||
// Example 3: for<'a> for<'b> Trait1<'a, 'b>: Trait2<'a /*ok*/, 'b /*not ok*/>
|
||
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
||
|
||
// Parse type with mandatory colon and (possibly empty) bounds,
|
||
// or with mandatory equality sign and the second type.
|
||
let ty = self.parse_ty()?;
|
||
if self.eat(&token::Colon) {
|
||
let bounds = self.parse_generic_bounds(None)?;
|
||
where_clause.predicates.push(ast::WherePredicate::BoundPredicate(
|
||
ast::WhereBoundPredicate {
|
||
span: lo.to(self.prev_span),
|
||
bound_generic_params: lifetime_defs,
|
||
bounded_ty: ty,
|
||
bounds,
|
||
}
|
||
));
|
||
// FIXME: Decide what should be used here, `=` or `==`.
|
||
// FIXME: We are just dropping the binders in lifetime_defs on the floor here.
|
||
} else if self.eat(&token::Eq) || self.eat(&token::EqEq) {
|
||
let rhs_ty = self.parse_ty()?;
|
||
where_clause.predicates.push(ast::WherePredicate::EqPredicate(
|
||
ast::WhereEqPredicate {
|
||
span: lo.to(self.prev_span),
|
||
lhs_ty: ty,
|
||
rhs_ty,
|
||
id: ast::DUMMY_NODE_ID,
|
||
}
|
||
));
|
||
} else {
|
||
return self.unexpected();
|
||
}
|
||
} else {
|
||
break
|
||
}
|
||
|
||
if !self.eat(&token::Comma) {
|
||
break
|
||
}
|
||
}
|
||
|
||
where_clause.span = lo.to(self.prev_span);
|
||
Ok(where_clause)
|
||
}
|
||
|
||
fn parse_fn_args(&mut self, named_args: bool, allow_variadic: bool)
|
||
-> PResult<'a, (Vec<Arg> , bool)> {
|
||
self.expect(&token::OpenDelim(token::Paren))?;
|
||
|
||
let sp = self.span;
|
||
let mut variadic = false;
|
||
let (args, recovered): (Vec<Option<Arg>>, bool) =
|
||
self.parse_seq_to_before_end(
|
||
&token::CloseDelim(token::Paren),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| {
|
||
if p.token == token::DotDotDot {
|
||
p.bump();
|
||
variadic = true;
|
||
if allow_variadic {
|
||
if p.token != token::CloseDelim(token::Paren) {
|
||
let span = p.span;
|
||
p.span_err(span,
|
||
"`...` must be last in argument list for variadic function");
|
||
}
|
||
Ok(None)
|
||
} else {
|
||
let span = p.prev_span;
|
||
if p.token == token::CloseDelim(token::Paren) {
|
||
// continue parsing to present any further errors
|
||
p.struct_span_err(
|
||
span,
|
||
"only foreign functions are allowed to be variadic"
|
||
).emit();
|
||
Ok(Some(dummy_arg(span)))
|
||
} else {
|
||
// this function definition looks beyond recovery, stop parsing
|
||
p.span_err(span,
|
||
"only foreign functions are allowed to be variadic");
|
||
Ok(None)
|
||
}
|
||
}
|
||
} else {
|
||
match p.parse_arg_general(named_args, false) {
|
||
Ok(arg) => Ok(Some(arg)),
|
||
Err(mut e) => {
|
||
e.emit();
|
||
let lo = p.prev_span;
|
||
// Skip every token until next possible arg or end.
|
||
p.eat_to_tokens(&[&token::Comma, &token::CloseDelim(token::Paren)]);
|
||
// Create a placeholder argument for proper arg count (#34264).
|
||
let span = lo.to(p.prev_span);
|
||
Ok(Some(dummy_arg(span)))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
)?;
|
||
|
||
if !recovered {
|
||
self.eat(&token::CloseDelim(token::Paren));
|
||
}
|
||
|
||
let args: Vec<_> = args.into_iter().filter_map(|x| x).collect();
|
||
|
||
if variadic && args.is_empty() {
|
||
self.span_err(sp,
|
||
"variadic function must be declared with at least one named argument");
|
||
}
|
||
|
||
Ok((args, variadic))
|
||
}
|
||
|
||
/// Parses the argument list and result type of a function declaration.
|
||
fn parse_fn_decl(&mut self, allow_variadic: bool) -> PResult<'a, P<FnDecl>> {
|
||
|
||
let (args, variadic) = self.parse_fn_args(true, allow_variadic)?;
|
||
let ret_ty = self.parse_ret_ty(true)?;
|
||
|
||
Ok(P(FnDecl {
|
||
inputs: args,
|
||
output: ret_ty,
|
||
variadic,
|
||
}))
|
||
}
|
||
|
||
/// Returns the parsed optional self argument and whether a self shortcut was used.
|
||
fn parse_self_arg(&mut self) -> PResult<'a, Option<Arg>> {
|
||
let expect_ident = |this: &mut Self| match this.token {
|
||
// Preserve hygienic context.
|
||
token::Ident(ident, _) =>
|
||
{ let span = this.span; this.bump(); Ident::new(ident.name, span) }
|
||
_ => unreachable!()
|
||
};
|
||
let isolated_self = |this: &mut Self, n| {
|
||
this.look_ahead(n, |t| t.is_keyword(keywords::SelfLower)) &&
|
||
this.look_ahead(n + 1, |t| t != &token::ModSep)
|
||
};
|
||
|
||
// Parse optional self parameter of a method.
|
||
// Only a limited set of initial token sequences is considered self parameters, anything
|
||
// else is parsed as a normal function parameter list, so some lookahead is required.
|
||
let eself_lo = self.span;
|
||
let (eself, eself_ident, eself_hi) = match self.token {
|
||
token::BinOp(token::And) => {
|
||
// &self
|
||
// &mut self
|
||
// &'lt self
|
||
// &'lt mut self
|
||
// ¬_self
|
||
(if isolated_self(self, 1) {
|
||
self.bump();
|
||
SelfKind::Region(None, Mutability::Immutable)
|
||
} else if self.look_ahead(1, |t| t.is_keyword(keywords::Mut)) &&
|
||
isolated_self(self, 2) {
|
||
self.bump();
|
||
self.bump();
|
||
SelfKind::Region(None, Mutability::Mutable)
|
||
} else if self.look_ahead(1, |t| t.is_lifetime()) &&
|
||
isolated_self(self, 2) {
|
||
self.bump();
|
||
let lt = self.expect_lifetime();
|
||
SelfKind::Region(Some(lt), Mutability::Immutable)
|
||
} else if self.look_ahead(1, |t| t.is_lifetime()) &&
|
||
self.look_ahead(2, |t| t.is_keyword(keywords::Mut)) &&
|
||
isolated_self(self, 3) {
|
||
self.bump();
|
||
let lt = self.expect_lifetime();
|
||
self.bump();
|
||
SelfKind::Region(Some(lt), Mutability::Mutable)
|
||
} else {
|
||
return Ok(None);
|
||
}, expect_ident(self), self.prev_span)
|
||
}
|
||
token::BinOp(token::Star) => {
|
||
// *self
|
||
// *const self
|
||
// *mut self
|
||
// *not_self
|
||
// Emit special error for `self` cases.
|
||
let msg = "cannot pass `self` by raw pointer";
|
||
(if isolated_self(self, 1) {
|
||
self.bump();
|
||
self.struct_span_err(self.span, msg)
|
||
.span_label(self.span, msg)
|
||
.emit();
|
||
SelfKind::Value(Mutability::Immutable)
|
||
} else if self.look_ahead(1, |t| t.is_mutability()) &&
|
||
isolated_self(self, 2) {
|
||
self.bump();
|
||
self.bump();
|
||
self.struct_span_err(self.span, msg)
|
||
.span_label(self.span, msg)
|
||
.emit();
|
||
SelfKind::Value(Mutability::Immutable)
|
||
} else {
|
||
return Ok(None);
|
||
}, expect_ident(self), self.prev_span)
|
||
}
|
||
token::Ident(..) => {
|
||
if isolated_self(self, 0) {
|
||
// self
|
||
// self: TYPE
|
||
let eself_ident = expect_ident(self);
|
||
let eself_hi = self.prev_span;
|
||
(if self.eat(&token::Colon) {
|
||
let ty = self.parse_ty()?;
|
||
SelfKind::Explicit(ty, Mutability::Immutable)
|
||
} else {
|
||
SelfKind::Value(Mutability::Immutable)
|
||
}, eself_ident, eself_hi)
|
||
} else if self.token.is_keyword(keywords::Mut) &&
|
||
isolated_self(self, 1) {
|
||
// mut self
|
||
// mut self: TYPE
|
||
self.bump();
|
||
let eself_ident = expect_ident(self);
|
||
let eself_hi = self.prev_span;
|
||
(if self.eat(&token::Colon) {
|
||
let ty = self.parse_ty()?;
|
||
SelfKind::Explicit(ty, Mutability::Mutable)
|
||
} else {
|
||
SelfKind::Value(Mutability::Mutable)
|
||
}, eself_ident, eself_hi)
|
||
} else {
|
||
return Ok(None);
|
||
}
|
||
}
|
||
_ => return Ok(None),
|
||
};
|
||
|
||
let eself = source_map::respan(eself_lo.to(eself_hi), eself);
|
||
Ok(Some(Arg::from_self(eself, eself_ident)))
|
||
}
|
||
|
||
/// Parses the parameter list and result type of a function that may have a `self` parameter.
|
||
fn parse_fn_decl_with_self<F>(&mut self, parse_arg_fn: F) -> PResult<'a, P<FnDecl>>
|
||
where F: FnMut(&mut Parser<'a>) -> PResult<'a, Arg>,
|
||
{
|
||
self.expect(&token::OpenDelim(token::Paren))?;
|
||
|
||
// Parse optional self argument
|
||
let self_arg = self.parse_self_arg()?;
|
||
|
||
// Parse the rest of the function parameter list.
|
||
let sep = SeqSep::trailing_allowed(token::Comma);
|
||
let (fn_inputs, recovered) = if let Some(self_arg) = self_arg {
|
||
if self.check(&token::CloseDelim(token::Paren)) {
|
||
(vec![self_arg], false)
|
||
} else if self.eat(&token::Comma) {
|
||
let mut fn_inputs = vec![self_arg];
|
||
let (mut input, recovered) = self.parse_seq_to_before_end(
|
||
&token::CloseDelim(token::Paren), sep, parse_arg_fn)?;
|
||
fn_inputs.append(&mut input);
|
||
(fn_inputs, recovered)
|
||
} else {
|
||
return self.unexpected();
|
||
}
|
||
} else {
|
||
self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)?
|
||
};
|
||
|
||
if !recovered {
|
||
// Parse closing paren and return type.
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
}
|
||
Ok(P(FnDecl {
|
||
inputs: fn_inputs,
|
||
output: self.parse_ret_ty(true)?,
|
||
variadic: false
|
||
}))
|
||
}
|
||
|
||
/// Parses the `|arg, arg|` header of a closure.
|
||
fn parse_fn_block_decl(&mut self) -> PResult<'a, P<FnDecl>> {
|
||
let inputs_captures = {
|
||
if self.eat(&token::OrOr) {
|
||
Vec::new()
|
||
} else {
|
||
self.expect(&token::BinOp(token::Or))?;
|
||
let args = self.parse_seq_to_before_tokens(
|
||
&[&token::BinOp(token::Or), &token::OrOr],
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
TokenExpectType::NoExpect,
|
||
|p| p.parse_fn_block_arg()
|
||
)?.0;
|
||
self.expect_or()?;
|
||
args
|
||
}
|
||
};
|
||
let output = self.parse_ret_ty(true)?;
|
||
|
||
Ok(P(FnDecl {
|
||
inputs: inputs_captures,
|
||
output,
|
||
variadic: false
|
||
}))
|
||
}
|
||
|
||
/// Parses the name and optional generic types of a function header.
|
||
fn parse_fn_header(&mut self) -> PResult<'a, (Ident, ast::Generics)> {
|
||
let id = self.parse_ident()?;
|
||
let generics = self.parse_generics()?;
|
||
Ok((id, generics))
|
||
}
|
||
|
||
fn mk_item(&mut self, span: Span, ident: Ident, node: ItemKind, vis: Visibility,
|
||
attrs: Vec<Attribute>) -> P<Item> {
|
||
P(Item {
|
||
ident,
|
||
attrs,
|
||
id: ast::DUMMY_NODE_ID,
|
||
node,
|
||
vis,
|
||
span,
|
||
tokens: None,
|
||
})
|
||
}
|
||
|
||
/// Parses an item-position function declaration.
|
||
fn parse_item_fn(&mut self,
|
||
unsafety: Unsafety,
|
||
asyncness: IsAsync,
|
||
constness: Spanned<Constness>,
|
||
abi: Abi)
|
||
-> PResult<'a, ItemInfo> {
|
||
let (ident, mut generics) = self.parse_fn_header()?;
|
||
let decl = self.parse_fn_decl(false)?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
|
||
let header = FnHeader { unsafety, asyncness, constness, abi };
|
||
Ok((ident, ItemKind::Fn(decl, header, generics, body), Some(inner_attrs)))
|
||
}
|
||
|
||
/// Returns `true` if we are looking at `const ID`
|
||
/// (returns `false` for things like `const fn`, etc.).
|
||
fn is_const_item(&mut self) -> bool {
|
||
self.token.is_keyword(keywords::Const) &&
|
||
!self.look_ahead(1, |t| t.is_keyword(keywords::Fn)) &&
|
||
!self.look_ahead(1, |t| t.is_keyword(keywords::Unsafe))
|
||
}
|
||
|
||
/// Parses all the "front matter" for a `fn` declaration, up to
|
||
/// and including the `fn` keyword:
|
||
///
|
||
/// - `const fn`
|
||
/// - `unsafe fn`
|
||
/// - `const unsafe fn`
|
||
/// - `extern fn`
|
||
/// - etc.
|
||
fn parse_fn_front_matter(&mut self)
|
||
-> PResult<'a, (
|
||
Spanned<Constness>,
|
||
Unsafety,
|
||
IsAsync,
|
||
Abi
|
||
)>
|
||
{
|
||
let is_const_fn = self.eat_keyword(keywords::Const);
|
||
let const_span = self.prev_span;
|
||
let unsafety = self.parse_unsafety();
|
||
let asyncness = self.parse_asyncness();
|
||
let (constness, unsafety, abi) = if is_const_fn {
|
||
(respan(const_span, Constness::Const), unsafety, Abi::Rust)
|
||
} else {
|
||
let abi = if self.eat_keyword(keywords::Extern) {
|
||
self.parse_opt_abi()?.unwrap_or(Abi::C)
|
||
} else {
|
||
Abi::Rust
|
||
};
|
||
(respan(self.prev_span, Constness::NotConst), unsafety, abi)
|
||
};
|
||
self.expect_keyword(keywords::Fn)?;
|
||
Ok((constness, unsafety, asyncness, abi))
|
||
}
|
||
|
||
/// Parses an impl item.
|
||
pub fn parse_impl_item(&mut self, at_end: &mut bool) -> PResult<'a, ImplItem> {
|
||
maybe_whole!(self, NtImplItem, |x| x);
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let (mut item, tokens) = self.collect_tokens(|this| {
|
||
this.parse_impl_item_(at_end, attrs)
|
||
})?;
|
||
|
||
// See `parse_item` for why this clause is here.
|
||
if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
|
||
item.tokens = Some(tokens);
|
||
}
|
||
Ok(item)
|
||
}
|
||
|
||
fn parse_impl_item_(&mut self,
|
||
at_end: &mut bool,
|
||
mut attrs: Vec<Attribute>) -> PResult<'a, ImplItem> {
|
||
let lo = self.span;
|
||
let vis = self.parse_visibility(false)?;
|
||
let defaultness = self.parse_defaultness();
|
||
let (name, node, generics) = if let Some(type_) = self.eat_type() {
|
||
let (name, alias, generics) = type_?;
|
||
let kind = match alias {
|
||
AliasKind::Weak(typ) => ast::ImplItemKind::Type(typ),
|
||
AliasKind::Existential(bounds) => ast::ImplItemKind::Existential(bounds),
|
||
};
|
||
(name, kind, generics)
|
||
} else if self.is_const_item() {
|
||
// This parses the grammar:
|
||
// ImplItemConst = "const" Ident ":" Ty "=" Expr ";"
|
||
self.expect_keyword(keywords::Const)?;
|
||
let name = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let typ = self.parse_ty()?;
|
||
self.expect(&token::Eq)?;
|
||
let expr = self.parse_expr()?;
|
||
self.expect(&token::Semi)?;
|
||
(name, ast::ImplItemKind::Const(typ, expr), ast::Generics::default())
|
||
} else {
|
||
let (name, inner_attrs, generics, node) = self.parse_impl_method(&vis, at_end)?;
|
||
attrs.extend(inner_attrs);
|
||
(name, node, generics)
|
||
};
|
||
|
||
Ok(ImplItem {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(self.prev_span),
|
||
ident: name,
|
||
vis,
|
||
defaultness,
|
||
attrs,
|
||
generics,
|
||
node,
|
||
tokens: None,
|
||
})
|
||
}
|
||
|
||
fn complain_if_pub_macro(&mut self, vis: &VisibilityKind, sp: Span) {
|
||
match *vis {
|
||
VisibilityKind::Inherited => {}
|
||
_ => {
|
||
let is_macro_rules: bool = match self.token {
|
||
token::Ident(sid, _) => sid.name == Symbol::intern("macro_rules"),
|
||
_ => false,
|
||
};
|
||
let mut err = if is_macro_rules {
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "can't qualify macro_rules invocation with `pub`");
|
||
err.span_suggestion(
|
||
sp,
|
||
"try exporting the macro",
|
||
"#[macro_export]".to_owned(),
|
||
Applicability::MaybeIncorrect // speculative
|
||
);
|
||
err
|
||
} else {
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "can't qualify macro invocation with `pub`");
|
||
err.help("try adjusting the macro to put `pub` inside the invocation");
|
||
err
|
||
};
|
||
err.emit();
|
||
}
|
||
}
|
||
}
|
||
|
||
fn missing_assoc_item_kind_err(&mut self, item_type: &str, prev_span: Span)
|
||
-> DiagnosticBuilder<'a>
|
||
{
|
||
let expected_kinds = if item_type == "extern" {
|
||
"missing `fn`, `type`, or `static`"
|
||
} else {
|
||
"missing `fn`, `type`, or `const`"
|
||
};
|
||
|
||
// Given this code `path(`, it seems like this is not
|
||
// setting the visibility of a macro invocation, but rather
|
||
// a mistyped method declaration.
|
||
// Create a diagnostic pointing out that `fn` is missing.
|
||
//
|
||
// x | pub path(&self) {
|
||
// | ^ missing `fn`, `type`, or `const`
|
||
// pub path(
|
||
// ^^ `sp` below will point to this
|
||
let sp = prev_span.between(self.prev_span);
|
||
let mut err = self.diagnostic().struct_span_err(
|
||
sp,
|
||
&format!("{} for {}-item declaration",
|
||
expected_kinds, item_type));
|
||
err.span_label(sp, expected_kinds);
|
||
err
|
||
}
|
||
|
||
/// Parse a method or a macro invocation in a trait impl.
|
||
fn parse_impl_method(&mut self, vis: &Visibility, at_end: &mut bool)
|
||
-> PResult<'a, (Ident, Vec<Attribute>, ast::Generics,
|
||
ast::ImplItemKind)> {
|
||
// code copied from parse_macro_use_or_failure... abstraction!
|
||
if let Some(mac) = self.parse_assoc_macro_invoc("impl", Some(vis), at_end)? {
|
||
// method macro
|
||
Ok((keywords::Invalid.ident(), vec![], ast::Generics::default(),
|
||
ast::ImplItemKind::Macro(mac)))
|
||
} else {
|
||
let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?;
|
||
let ident = self.parse_ident()?;
|
||
let mut generics = self.parse_generics()?;
|
||
let decl = self.parse_fn_decl_with_self(|p| p.parse_arg())?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
*at_end = true;
|
||
let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
|
||
let header = ast::FnHeader { abi, unsafety, constness, asyncness };
|
||
Ok((ident, inner_attrs, generics, ast::ImplItemKind::Method(
|
||
ast::MethodSig { header, decl },
|
||
body
|
||
)))
|
||
}
|
||
}
|
||
|
||
/// Parses `trait Foo { ... }` or `trait Foo = Bar;`.
|
||
fn parse_item_trait(&mut self, is_auto: IsAuto, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
|
||
let ident = self.parse_ident()?;
|
||
let mut tps = self.parse_generics()?;
|
||
|
||
// Parse optional colon and supertrait bounds.
|
||
let bounds = if self.eat(&token::Colon) {
|
||
self.parse_generic_bounds(Some(self.prev_span))?
|
||
} else {
|
||
Vec::new()
|
||
};
|
||
|
||
if self.eat(&token::Eq) {
|
||
// it's a trait alias
|
||
let bounds = self.parse_generic_bounds(None)?;
|
||
tps.where_clause = self.parse_where_clause()?;
|
||
self.expect(&token::Semi)?;
|
||
if is_auto == IsAuto::Yes {
|
||
let msg = "trait aliases cannot be `auto`";
|
||
self.struct_span_err(self.prev_span, msg)
|
||
.span_label(self.prev_span, msg)
|
||
.emit();
|
||
}
|
||
if unsafety != Unsafety::Normal {
|
||
let msg = "trait aliases cannot be `unsafe`";
|
||
self.struct_span_err(self.prev_span, msg)
|
||
.span_label(self.prev_span, msg)
|
||
.emit();
|
||
}
|
||
Ok((ident, ItemKind::TraitAlias(tps, bounds), None))
|
||
} else {
|
||
// it's a normal trait
|
||
tps.where_clause = self.parse_where_clause()?;
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
let mut trait_items = vec![];
|
||
while !self.eat(&token::CloseDelim(token::Brace)) {
|
||
let mut at_end = false;
|
||
match self.parse_trait_item(&mut at_end) {
|
||
Ok(item) => trait_items.push(item),
|
||
Err(mut e) => {
|
||
e.emit();
|
||
if !at_end {
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
Ok((ident, ItemKind::Trait(is_auto, unsafety, tps, bounds, trait_items), None))
|
||
}
|
||
}
|
||
|
||
fn choose_generics_over_qpath(&self) -> bool {
|
||
// There's an ambiguity between generic parameters and qualified paths in impls.
|
||
// If we see `<` it may start both, so we have to inspect some following tokens.
|
||
// The following combinations can only start generics,
|
||
// but not qualified paths (with one exception):
|
||
// `<` `>` - empty generic parameters
|
||
// `<` `#` - generic parameters with attributes
|
||
// `<` (LIFETIME|IDENT) `>` - single generic parameter
|
||
// `<` (LIFETIME|IDENT) `,` - first generic parameter in a list
|
||
// `<` (LIFETIME|IDENT) `:` - generic parameter with bounds
|
||
// `<` (LIFETIME|IDENT) `=` - generic parameter with a default
|
||
// `<` const - generic const parameter
|
||
// The only truly ambiguous case is
|
||
// `<` IDENT `>` `::` IDENT ...
|
||
// we disambiguate it in favor of generics (`impl<T> ::absolute::Path<T> { ... }`)
|
||
// because this is what almost always expected in practice, qualified paths in impls
|
||
// (`impl <Type>::AssocTy { ... }`) aren't even allowed by type checker at the moment.
|
||
self.token == token::Lt &&
|
||
(self.look_ahead(1, |t| t == &token::Pound || t == &token::Gt) ||
|
||
self.look_ahead(1, |t| t.is_lifetime() || t.is_ident()) &&
|
||
self.look_ahead(2, |t| t == &token::Gt || t == &token::Comma ||
|
||
t == &token::Colon || t == &token::Eq) ||
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Const)))
|
||
}
|
||
|
||
fn parse_impl_body(&mut self) -> PResult<'a, (Vec<ImplItem>, Vec<Attribute>)> {
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
let attrs = self.parse_inner_attributes()?;
|
||
|
||
let mut impl_items = Vec::new();
|
||
while !self.eat(&token::CloseDelim(token::Brace)) {
|
||
let mut at_end = false;
|
||
match self.parse_impl_item(&mut at_end) {
|
||
Ok(impl_item) => impl_items.push(impl_item),
|
||
Err(mut err) => {
|
||
err.emit();
|
||
if !at_end {
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
Ok((impl_items, attrs))
|
||
}
|
||
|
||
/// Parses an implementation item, `impl` keyword is already parsed.
|
||
///
|
||
/// impl<'a, T> TYPE { /* impl items */ }
|
||
/// impl<'a, T> TRAIT for TYPE { /* impl items */ }
|
||
/// impl<'a, T> !TRAIT for TYPE { /* impl items */ }
|
||
///
|
||
/// We actually parse slightly more relaxed grammar for better error reporting and recovery.
|
||
/// `impl` GENERICS `!`? TYPE `for`? (TYPE | `..`) (`where` PREDICATES)? `{` BODY `}`
|
||
/// `impl` GENERICS `!`? TYPE (`where` PREDICATES)? `{` BODY `}`
|
||
fn parse_item_impl(&mut self, unsafety: Unsafety, defaultness: Defaultness)
|
||
-> PResult<'a, ItemInfo> {
|
||
// First, parse generic parameters if necessary.
|
||
let mut generics = if self.choose_generics_over_qpath() {
|
||
self.parse_generics()?
|
||
} else {
|
||
ast::Generics::default()
|
||
};
|
||
|
||
// Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type.
|
||
let polarity = if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) {
|
||
self.bump(); // `!`
|
||
ast::ImplPolarity::Negative
|
||
} else {
|
||
ast::ImplPolarity::Positive
|
||
};
|
||
|
||
// Parse both types and traits as a type, then reinterpret if necessary.
|
||
let ty_first = self.parse_ty()?;
|
||
|
||
// If `for` is missing we try to recover.
|
||
let has_for = self.eat_keyword(keywords::For);
|
||
let missing_for_span = self.prev_span.between(self.span);
|
||
|
||
let ty_second = if self.token == token::DotDot {
|
||
// We need to report this error after `cfg` expansion for compatibility reasons
|
||
self.bump(); // `..`, do not add it to expected tokens
|
||
Some(P(Ty { node: TyKind::Err, span: self.prev_span, id: ast::DUMMY_NODE_ID }))
|
||
} else if has_for || self.token.can_begin_type() {
|
||
Some(self.parse_ty()?)
|
||
} else {
|
||
None
|
||
};
|
||
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
|
||
let (impl_items, attrs) = self.parse_impl_body()?;
|
||
|
||
let item_kind = match ty_second {
|
||
Some(ty_second) => {
|
||
// impl Trait for Type
|
||
if !has_for {
|
||
self.struct_span_err(missing_for_span, "missing `for` in a trait impl")
|
||
.span_suggestion_short(
|
||
missing_for_span,
|
||
"add `for` here",
|
||
" for ".to_string(),
|
||
Applicability::MachineApplicable,
|
||
).emit();
|
||
}
|
||
|
||
let ty_first = ty_first.into_inner();
|
||
let path = match ty_first.node {
|
||
// This notably includes paths passed through `ty` macro fragments (#46438).
|
||
TyKind::Path(None, path) => path,
|
||
_ => {
|
||
self.span_err(ty_first.span, "expected a trait, found type");
|
||
ast::Path::from_ident(Ident::new(keywords::Invalid.name(), ty_first.span))
|
||
}
|
||
};
|
||
let trait_ref = TraitRef { path, ref_id: ty_first.id };
|
||
|
||
ItemKind::Impl(unsafety, polarity, defaultness,
|
||
generics, Some(trait_ref), ty_second, impl_items)
|
||
}
|
||
None => {
|
||
// impl Type
|
||
ItemKind::Impl(unsafety, polarity, defaultness,
|
||
generics, None, ty_first, impl_items)
|
||
}
|
||
};
|
||
|
||
Ok((keywords::Invalid.ident(), item_kind, Some(attrs)))
|
||
}
|
||
|
||
fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, Vec<GenericParam>> {
|
||
if self.eat_keyword(keywords::For) {
|
||
self.expect_lt()?;
|
||
let params = self.parse_generic_params()?;
|
||
self.expect_gt()?;
|
||
// We rely on AST validation to rule out invalid cases: There must not be type
|
||
// parameters, and the lifetime parameters must not have bounds.
|
||
Ok(params)
|
||
} else {
|
||
Ok(Vec::new())
|
||
}
|
||
}
|
||
|
||
/// Parses `struct Foo { ... }`.
|
||
fn parse_item_struct(&mut self) -> PResult<'a, ItemInfo> {
|
||
let class_name = self.parse_ident()?;
|
||
|
||
let mut generics = self.parse_generics()?;
|
||
|
||
// There is a special case worth noting here, as reported in issue #17904.
|
||
// If we are parsing a tuple struct it is the case that the where clause
|
||
// should follow the field list. Like so:
|
||
//
|
||
// struct Foo<T>(T) where T: Copy;
|
||
//
|
||
// If we are parsing a normal record-style struct it is the case
|
||
// that the where clause comes before the body, and after the generics.
|
||
// So if we look ahead and see a brace or a where-clause we begin
|
||
// parsing a record style struct.
|
||
//
|
||
// Otherwise if we look ahead and see a paren we parse a tuple-style
|
||
// struct.
|
||
|
||
let vdata = if self.token.is_keyword(keywords::Where) {
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
if self.eat(&token::Semi) {
|
||
// If we see a: `struct Foo<T> where T: Copy;` style decl.
|
||
VariantData::Unit(ast::DUMMY_NODE_ID)
|
||
} else {
|
||
// If we see: `struct Foo<T> where T: Copy { ... }`
|
||
VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
|
||
}
|
||
// No `where` so: `struct Foo<T>;`
|
||
} else if self.eat(&token::Semi) {
|
||
VariantData::Unit(ast::DUMMY_NODE_ID)
|
||
// Record-style struct definition
|
||
} else if self.token == token::OpenDelim(token::Brace) {
|
||
VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
|
||
// Tuple-style struct definition with optional where-clause.
|
||
} else if self.token == token::OpenDelim(token::Paren) {
|
||
let body = VariantData::Tuple(self.parse_tuple_struct_body()?, ast::DUMMY_NODE_ID);
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
self.expect(&token::Semi)?;
|
||
body
|
||
} else {
|
||
let token_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!(
|
||
"expected `where`, `{{`, `(`, or `;` after struct name, found {}",
|
||
token_str
|
||
));
|
||
err.span_label(self.span, "expected `where`, `{`, `(`, or `;` after struct name");
|
||
return Err(err);
|
||
};
|
||
|
||
Ok((class_name, ItemKind::Struct(vdata, generics), None))
|
||
}
|
||
|
||
/// Parses `union Foo { ... }`.
|
||
fn parse_item_union(&mut self) -> PResult<'a, ItemInfo> {
|
||
let class_name = self.parse_ident()?;
|
||
|
||
let mut generics = self.parse_generics()?;
|
||
|
||
let vdata = if self.token.is_keyword(keywords::Where) {
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
|
||
} else if self.token == token::OpenDelim(token::Brace) {
|
||
VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
|
||
} else {
|
||
let token_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!(
|
||
"expected `where` or `{{` after union name, found {}", token_str));
|
||
err.span_label(self.span, "expected `where` or `{` after union name");
|
||
return Err(err);
|
||
};
|
||
|
||
Ok((class_name, ItemKind::Union(vdata, generics), None))
|
||
}
|
||
|
||
fn consume_block(&mut self, delim: token::DelimToken) {
|
||
let mut brace_depth = 0;
|
||
loop {
|
||
if self.eat(&token::OpenDelim(delim)) {
|
||
brace_depth += 1;
|
||
} else if self.eat(&token::CloseDelim(delim)) {
|
||
if brace_depth == 0 {
|
||
return;
|
||
} else {
|
||
brace_depth -= 1;
|
||
continue;
|
||
}
|
||
} else if self.token == token::Eof || self.eat(&token::CloseDelim(token::NoDelim)) {
|
||
return;
|
||
} else {
|
||
self.bump();
|
||
}
|
||
}
|
||
}
|
||
|
||
fn parse_record_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
|
||
let mut fields = Vec::new();
|
||
if self.eat(&token::OpenDelim(token::Brace)) {
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
let field = self.parse_struct_decl_field().map_err(|e| {
|
||
self.recover_stmt();
|
||
e
|
||
});
|
||
match field {
|
||
Ok(field) => fields.push(field),
|
||
Err(mut err) => {
|
||
err.emit();
|
||
}
|
||
}
|
||
}
|
||
self.eat(&token::CloseDelim(token::Brace));
|
||
} else {
|
||
let token_str = self.this_token_descr();
|
||
let mut err = self.fatal(&format!(
|
||
"expected `where`, or `{{` after struct name, found {}", token_str));
|
||
err.span_label(self.span, "expected `where`, or `{` after struct name");
|
||
return Err(err);
|
||
}
|
||
|
||
Ok(fields)
|
||
}
|
||
|
||
fn parse_tuple_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
|
||
// This is the case where we find `struct Foo<T>(T) where T: Copy;`
|
||
// Unit like structs are handled in parse_item_struct function
|
||
let fields = self.parse_unspanned_seq(
|
||
&token::OpenDelim(token::Paren),
|
||
&token::CloseDelim(token::Paren),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| {
|
||
let attrs = p.parse_outer_attributes()?;
|
||
let lo = p.span;
|
||
let vis = p.parse_visibility(true)?;
|
||
let ty = p.parse_ty()?;
|
||
Ok(StructField {
|
||
span: lo.to(ty.span),
|
||
vis,
|
||
ident: None,
|
||
id: ast::DUMMY_NODE_ID,
|
||
ty,
|
||
attrs,
|
||
})
|
||
})?;
|
||
|
||
Ok(fields)
|
||
}
|
||
|
||
/// Parses a structure field declaration.
|
||
fn parse_single_struct_field(&mut self,
|
||
lo: Span,
|
||
vis: Visibility,
|
||
attrs: Vec<Attribute> )
|
||
-> PResult<'a, StructField> {
|
||
let mut seen_comma: bool = false;
|
||
let a_var = self.parse_name_and_ty(lo, vis, attrs)?;
|
||
if self.token == token::Comma {
|
||
seen_comma = true;
|
||
}
|
||
match self.token {
|
||
token::Comma => {
|
||
self.bump();
|
||
}
|
||
token::CloseDelim(token::Brace) => {}
|
||
token::DocComment(_) => {
|
||
let previous_span = self.prev_span;
|
||
let mut err = self.span_fatal_err(self.span, Error::UselessDocComment);
|
||
self.bump(); // consume the doc comment
|
||
let comma_after_doc_seen = self.eat(&token::Comma);
|
||
// `seen_comma` is always false, because we are inside doc block
|
||
// condition is here to make code more readable
|
||
if seen_comma == false && comma_after_doc_seen == true {
|
||
seen_comma = true;
|
||
}
|
||
if comma_after_doc_seen || self.token == token::CloseDelim(token::Brace) {
|
||
err.emit();
|
||
} else {
|
||
if seen_comma == false {
|
||
let sp = self.sess.source_map().next_point(previous_span);
|
||
err.span_suggestion(
|
||
sp,
|
||
"missing comma here",
|
||
",".into(),
|
||
Applicability::MachineApplicable
|
||
);
|
||
}
|
||
return Err(err);
|
||
}
|
||
}
|
||
_ => {
|
||
let sp = self.sess.source_map().next_point(self.prev_span);
|
||
let mut err = self.struct_span_err(sp, &format!("expected `,`, or `}}`, found {}",
|
||
self.this_token_descr()));
|
||
if self.token.is_ident() {
|
||
// This is likely another field; emit the diagnostic and keep going
|
||
err.span_suggestion(
|
||
sp,
|
||
"try adding a comma",
|
||
",".into(),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
err.emit();
|
||
} else {
|
||
return Err(err)
|
||
}
|
||
}
|
||
}
|
||
Ok(a_var)
|
||
}
|
||
|
||
/// Parses an element of a struct declaration.
|
||
fn parse_struct_decl_field(&mut self) -> PResult<'a, StructField> {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
let vis = self.parse_visibility(false)?;
|
||
self.parse_single_struct_field(lo, vis, attrs)
|
||
}
|
||
|
||
/// Parses `pub`, `pub(crate)` and `pub(in path)` plus shortcuts `crate` for `pub(crate)`,
|
||
/// `pub(self)` for `pub(in self)` and `pub(super)` for `pub(in super)`.
|
||
/// If the following element can't be a tuple (i.e., it's a function definition), then
|
||
/// it's not a tuple struct field), and the contents within the parentheses isn't valid,
|
||
/// so emit a proper diagnostic.
|
||
pub fn parse_visibility(&mut self, can_take_tuple: bool) -> PResult<'a, Visibility> {
|
||
maybe_whole!(self, NtVis, |x| x);
|
||
|
||
self.expected_tokens.push(TokenType::Keyword(keywords::Crate));
|
||
if self.is_crate_vis() {
|
||
self.bump(); // `crate`
|
||
return Ok(respan(self.prev_span, VisibilityKind::Crate(CrateSugar::JustCrate)));
|
||
}
|
||
|
||
if !self.eat_keyword(keywords::Pub) {
|
||
// We need a span for our `Spanned<VisibilityKind>`, but there's inherently no
|
||
// keyword to grab a span from for inherited visibility; an empty span at the
|
||
// beginning of the current token would seem to be the "Schelling span".
|
||
return Ok(respan(self.span.shrink_to_lo(), VisibilityKind::Inherited))
|
||
}
|
||
let lo = self.prev_span;
|
||
|
||
if self.check(&token::OpenDelim(token::Paren)) {
|
||
// We don't `self.bump()` the `(` yet because this might be a struct definition where
|
||
// `()` or a tuple might be allowed. For example, `struct Struct(pub (), pub (usize));`.
|
||
// Because of this, we only `bump` the `(` if we're assured it is appropriate to do so
|
||
// by the following tokens.
|
||
if self.look_ahead(1, |t| t.is_keyword(keywords::Crate)) {
|
||
// `pub(crate)`
|
||
self.bump(); // `(`
|
||
self.bump(); // `crate`
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
let vis = respan(
|
||
lo.to(self.prev_span),
|
||
VisibilityKind::Crate(CrateSugar::PubCrate),
|
||
);
|
||
return Ok(vis)
|
||
} else if self.look_ahead(1, |t| t.is_keyword(keywords::In)) {
|
||
// `pub(in path)`
|
||
self.bump(); // `(`
|
||
self.bump(); // `in`
|
||
let path = self.parse_path(PathStyle::Mod)?; // `path`
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
let vis = respan(lo.to(self.prev_span), VisibilityKind::Restricted {
|
||
path: P(path),
|
||
id: ast::DUMMY_NODE_ID,
|
||
});
|
||
return Ok(vis)
|
||
} else if self.look_ahead(2, |t| t == &token::CloseDelim(token::Paren)) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Super) ||
|
||
t.is_keyword(keywords::SelfLower))
|
||
{
|
||
// `pub(self)` or `pub(super)`
|
||
self.bump(); // `(`
|
||
let path = self.parse_path(PathStyle::Mod)?; // `super`/`self`
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
let vis = respan(lo.to(self.prev_span), VisibilityKind::Restricted {
|
||
path: P(path),
|
||
id: ast::DUMMY_NODE_ID,
|
||
});
|
||
return Ok(vis)
|
||
} else if !can_take_tuple { // Provide this diagnostic if this is not a tuple struct
|
||
// `pub(something) fn ...` or `struct X { pub(something) y: Z }`
|
||
self.bump(); // `(`
|
||
let msg = "incorrect visibility restriction";
|
||
let suggestion = r##"some possible visibility restrictions are:
|
||
`pub(crate)`: visible only on the current crate
|
||
`pub(super)`: visible only in the current module's parent
|
||
`pub(in path::to::module)`: visible only on the specified path"##;
|
||
let path = self.parse_path(PathStyle::Mod)?;
|
||
let sp = self.prev_span;
|
||
let help_msg = format!("make this visible only to module `{}` with `in`", path);
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
let mut err = struct_span_err!(self.sess.span_diagnostic, sp, E0704, "{}", msg);
|
||
err.help(suggestion);
|
||
err.span_suggestion(
|
||
sp, &help_msg, format!("in {}", path), Applicability::MachineApplicable
|
||
);
|
||
err.emit(); // emit diagnostic, but continue with public visibility
|
||
}
|
||
}
|
||
|
||
Ok(respan(lo, VisibilityKind::Public))
|
||
}
|
||
|
||
/// Parses defaultness (i.e., `default` or nothing).
|
||
fn parse_defaultness(&mut self) -> Defaultness {
|
||
// `pub` is included for better error messages
|
||
if self.check_keyword(keywords::Default) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Impl) ||
|
||
t.is_keyword(keywords::Const) ||
|
||
t.is_keyword(keywords::Fn) ||
|
||
t.is_keyword(keywords::Unsafe) ||
|
||
t.is_keyword(keywords::Extern) ||
|
||
t.is_keyword(keywords::Type) ||
|
||
t.is_keyword(keywords::Pub)) {
|
||
self.bump(); // `default`
|
||
Defaultness::Default
|
||
} else {
|
||
Defaultness::Final
|
||
}
|
||
}
|
||
|
||
fn maybe_consume_incorrect_semicolon(&mut self, items: &[P<Item>]) -> bool {
|
||
if self.eat(&token::Semi) {
|
||
let mut err = self.struct_span_err(self.prev_span, "expected item, found `;`");
|
||
err.span_suggestion_short(
|
||
self.prev_span,
|
||
"remove this semicolon",
|
||
String::new(),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
if !items.is_empty() {
|
||
let previous_item = &items[items.len()-1];
|
||
let previous_item_kind_name = match previous_item.node {
|
||
// say "braced struct" because tuple-structs and
|
||
// braceless-empty-struct declarations do take a semicolon
|
||
ItemKind::Struct(..) => Some("braced struct"),
|
||
ItemKind::Enum(..) => Some("enum"),
|
||
ItemKind::Trait(..) => Some("trait"),
|
||
ItemKind::Union(..) => Some("union"),
|
||
_ => None,
|
||
};
|
||
if let Some(name) = previous_item_kind_name {
|
||
err.help(&format!("{} declarations are not followed by a semicolon", name));
|
||
}
|
||
}
|
||
err.emit();
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
/// Given a termination token, parses all of the items in a module.
|
||
fn parse_mod_items(&mut self, term: &token::Token, inner_lo: Span) -> PResult<'a, Mod> {
|
||
let mut items = vec![];
|
||
while let Some(item) = self.parse_item()? {
|
||
items.push(item);
|
||
self.maybe_consume_incorrect_semicolon(&items);
|
||
}
|
||
|
||
if !self.eat(term) {
|
||
let token_str = self.this_token_descr();
|
||
if !self.maybe_consume_incorrect_semicolon(&items) {
|
||
let mut err = self.fatal(&format!("expected item, found {}", token_str));
|
||
err.span_label(self.span, "expected item");
|
||
return Err(err);
|
||
}
|
||
}
|
||
|
||
let hi = if self.span.is_dummy() {
|
||
inner_lo
|
||
} else {
|
||
self.prev_span
|
||
};
|
||
|
||
Ok(ast::Mod {
|
||
inner: inner_lo.to(hi),
|
||
items,
|
||
inline: true
|
||
})
|
||
}
|
||
|
||
fn parse_item_const(&mut self, m: Option<Mutability>) -> PResult<'a, ItemInfo> {
|
||
let id = if m.is_none() { self.parse_ident_or_underscore() } else { self.parse_ident() }?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
self.expect(&token::Eq)?;
|
||
let e = self.parse_expr()?;
|
||
self.expect(&token::Semi)?;
|
||
let item = match m {
|
||
Some(m) => ItemKind::Static(ty, m, e),
|
||
None => ItemKind::Const(ty, e),
|
||
};
|
||
Ok((id, item, None))
|
||
}
|
||
|
||
/// Parse a `mod <foo> { ... }` or `mod <foo>;` item
|
||
fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
|
||
let (in_cfg, outer_attrs) = {
|
||
let mut strip_unconfigured = crate::config::StripUnconfigured {
|
||
sess: self.sess,
|
||
features: None, // don't perform gated feature checking
|
||
};
|
||
let mut outer_attrs = outer_attrs.to_owned();
|
||
strip_unconfigured.process_cfg_attrs(&mut outer_attrs);
|
||
(!self.cfg_mods || strip_unconfigured.in_cfg(&outer_attrs), outer_attrs)
|
||
};
|
||
|
||
let id_span = self.span;
|
||
let id = self.parse_ident()?;
|
||
if self.eat(&token::Semi) {
|
||
if in_cfg && self.recurse_into_file_modules {
|
||
// This mod is in an external file. Let's go get it!
|
||
let ModulePathSuccess { path, directory_ownership, warn } =
|
||
self.submod_path(id, &outer_attrs, id_span)?;
|
||
let (module, mut attrs) =
|
||
self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?;
|
||
// Record that we fetched the mod from an external file
|
||
if warn {
|
||
let attr = Attribute {
|
||
id: attr::mk_attr_id(),
|
||
style: ast::AttrStyle::Outer,
|
||
path: ast::Path::from_ident(Ident::from_str("warn_directory_ownership")),
|
||
tokens: TokenStream::empty(),
|
||
is_sugared_doc: false,
|
||
span: syntax_pos::DUMMY_SP,
|
||
};
|
||
attr::mark_known(&attr);
|
||
attrs.push(attr);
|
||
}
|
||
Ok((id, ItemKind::Mod(module), Some(attrs)))
|
||
} else {
|
||
let placeholder = ast::Mod {
|
||
inner: syntax_pos::DUMMY_SP,
|
||
items: Vec::new(),
|
||
inline: false
|
||
};
|
||
Ok((id, ItemKind::Mod(placeholder), None))
|
||
}
|
||
} else {
|
||
let old_directory = self.directory.clone();
|
||
self.push_directory(id, &outer_attrs);
|
||
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
let mod_inner_lo = self.span;
|
||
let attrs = self.parse_inner_attributes()?;
|
||
let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?;
|
||
|
||
self.directory = old_directory;
|
||
Ok((id, ItemKind::Mod(module), Some(attrs)))
|
||
}
|
||
}
|
||
|
||
fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
|
||
if let Some(path) = attr::first_attr_value_str_by_name(attrs, "path") {
|
||
self.directory.path.to_mut().push(&path.as_str());
|
||
self.directory.ownership = DirectoryOwnership::Owned { relative: None };
|
||
} else {
|
||
// We have to push on the current module name in the case of relative
|
||
// paths in order to ensure that any additional module paths from inline
|
||
// `mod x { ... }` come after the relative extension.
|
||
//
|
||
// For example, a `mod z { ... }` inside `x/y.rs` should set the current
|
||
// directory path to `/x/y/z`, not `/x/z` with a relative offset of `y`.
|
||
if let DirectoryOwnership::Owned { relative } = &mut self.directory.ownership {
|
||
if let Some(ident) = relative.take() { // remove the relative offset
|
||
self.directory.path.to_mut().push(ident.as_str());
|
||
}
|
||
}
|
||
self.directory.path.to_mut().push(&id.as_str());
|
||
}
|
||
}
|
||
|
||
pub fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> {
|
||
if let Some(s) = attr::first_attr_value_str_by_name(attrs, "path") {
|
||
let s = s.as_str();
|
||
|
||
// On windows, the base path might have the form
|
||
// `\\?\foo\bar` in which case it does not tolerate
|
||
// mixed `/` and `\` separators, so canonicalize
|
||
// `/` to `\`.
|
||
#[cfg(windows)]
|
||
let s = s.replace("/", "\\");
|
||
Some(dir_path.join(s))
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
/// Returns a path to a module.
|
||
pub fn default_submod_path(
|
||
id: ast::Ident,
|
||
relative: Option<ast::Ident>,
|
||
dir_path: &Path,
|
||
source_map: &SourceMap) -> ModulePath
|
||
{
|
||
// If we're in a foo.rs file instead of a mod.rs file,
|
||
// we need to look for submodules in
|
||
// `./foo/<id>.rs` and `./foo/<id>/mod.rs` rather than
|
||
// `./<id>.rs` and `./<id>/mod.rs`.
|
||
let relative_prefix_string;
|
||
let relative_prefix = if let Some(ident) = relative {
|
||
relative_prefix_string = format!("{}{}", ident.as_str(), path::MAIN_SEPARATOR);
|
||
&relative_prefix_string
|
||
} else {
|
||
""
|
||
};
|
||
|
||
let mod_name = id.to_string();
|
||
let default_path_str = format!("{}{}.rs", relative_prefix, mod_name);
|
||
let secondary_path_str = format!("{}{}{}mod.rs",
|
||
relative_prefix, mod_name, path::MAIN_SEPARATOR);
|
||
let default_path = dir_path.join(&default_path_str);
|
||
let secondary_path = dir_path.join(&secondary_path_str);
|
||
let default_exists = source_map.file_exists(&default_path);
|
||
let secondary_exists = source_map.file_exists(&secondary_path);
|
||
|
||
let result = match (default_exists, secondary_exists) {
|
||
(true, false) => Ok(ModulePathSuccess {
|
||
path: default_path,
|
||
directory_ownership: DirectoryOwnership::Owned {
|
||
relative: Some(id),
|
||
},
|
||
warn: false,
|
||
}),
|
||
(false, true) => Ok(ModulePathSuccess {
|
||
path: secondary_path,
|
||
directory_ownership: DirectoryOwnership::Owned {
|
||
relative: None,
|
||
},
|
||
warn: false,
|
||
}),
|
||
(false, false) => Err(Error::FileNotFoundForModule {
|
||
mod_name: mod_name.clone(),
|
||
default_path: default_path_str,
|
||
secondary_path: secondary_path_str,
|
||
dir_path: dir_path.display().to_string(),
|
||
}),
|
||
(true, true) => Err(Error::DuplicatePaths {
|
||
mod_name: mod_name.clone(),
|
||
default_path: default_path_str,
|
||
secondary_path: secondary_path_str,
|
||
}),
|
||
};
|
||
|
||
ModulePath {
|
||
name: mod_name,
|
||
path_exists: default_exists || secondary_exists,
|
||
result,
|
||
}
|
||
}
|
||
|
||
fn submod_path(&mut self,
|
||
id: ast::Ident,
|
||
outer_attrs: &[Attribute],
|
||
id_sp: Span)
|
||
-> PResult<'a, ModulePathSuccess> {
|
||
if let Some(path) = Parser::submod_path_from_attr(outer_attrs, &self.directory.path) {
|
||
return Ok(ModulePathSuccess {
|
||
directory_ownership: match path.file_name().and_then(|s| s.to_str()) {
|
||
// All `#[path]` files are treated as though they are a `mod.rs` file.
|
||
// This means that `mod foo;` declarations inside `#[path]`-included
|
||
// files are siblings,
|
||
//
|
||
// Note that this will produce weirdness when a file named `foo.rs` is
|
||
// `#[path]` included and contains a `mod foo;` declaration.
|
||
// If you encounter this, it's your own darn fault :P
|
||
Some(_) => DirectoryOwnership::Owned { relative: None },
|
||
_ => DirectoryOwnership::UnownedViaMod(true),
|
||
},
|
||
path,
|
||
warn: false,
|
||
});
|
||
}
|
||
|
||
let relative = match self.directory.ownership {
|
||
DirectoryOwnership::Owned { relative } => relative,
|
||
DirectoryOwnership::UnownedViaBlock |
|
||
DirectoryOwnership::UnownedViaMod(_) => None,
|
||
};
|
||
let paths = Parser::default_submod_path(
|
||
id, relative, &self.directory.path, self.sess.source_map());
|
||
|
||
match self.directory.ownership {
|
||
DirectoryOwnership::Owned { .. } => {
|
||
paths.result.map_err(|err| self.span_fatal_err(id_sp, err))
|
||
},
|
||
DirectoryOwnership::UnownedViaBlock => {
|
||
let msg =
|
||
"Cannot declare a non-inline module inside a block \
|
||
unless it has a path attribute";
|
||
let mut err = self.diagnostic().struct_span_err(id_sp, msg);
|
||
if paths.path_exists {
|
||
let msg = format!("Maybe `use` the module `{}` instead of redeclaring it",
|
||
paths.name);
|
||
err.span_note(id_sp, &msg);
|
||
}
|
||
Err(err)
|
||
}
|
||
DirectoryOwnership::UnownedViaMod(warn) => {
|
||
if warn {
|
||
if let Ok(result) = paths.result {
|
||
return Ok(ModulePathSuccess { warn: true, ..result });
|
||
}
|
||
}
|
||
let mut err = self.diagnostic().struct_span_err(id_sp,
|
||
"cannot declare a new module at this location");
|
||
if !id_sp.is_dummy() {
|
||
let src_path = self.sess.source_map().span_to_filename(id_sp);
|
||
if let FileName::Real(src_path) = src_path {
|
||
if let Some(stem) = src_path.file_stem() {
|
||
let mut dest_path = src_path.clone();
|
||
dest_path.set_file_name(stem);
|
||
dest_path.push("mod.rs");
|
||
err.span_note(id_sp,
|
||
&format!("maybe move this module `{}` to its own \
|
||
directory via `{}`", src_path.display(),
|
||
dest_path.display()));
|
||
}
|
||
}
|
||
}
|
||
if paths.path_exists {
|
||
err.span_note(id_sp,
|
||
&format!("... or maybe `use` the module `{}` instead \
|
||
of possibly redeclaring it",
|
||
paths.name));
|
||
}
|
||
Err(err)
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Reads a module from a source file.
|
||
fn eval_src_mod(&mut self,
|
||
path: PathBuf,
|
||
directory_ownership: DirectoryOwnership,
|
||
name: String,
|
||
id_sp: Span)
|
||
-> PResult<'a, (ast::Mod, Vec<Attribute> )> {
|
||
let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
|
||
if let Some(i) = included_mod_stack.iter().position(|p| *p == path) {
|
||
let mut err = String::from("circular modules: ");
|
||
let len = included_mod_stack.len();
|
||
for p in &included_mod_stack[i.. len] {
|
||
err.push_str(&p.to_string_lossy());
|
||
err.push_str(" -> ");
|
||
}
|
||
err.push_str(&path.to_string_lossy());
|
||
return Err(self.span_fatal(id_sp, &err[..]));
|
||
}
|
||
included_mod_stack.push(path.clone());
|
||
drop(included_mod_stack);
|
||
|
||
let mut p0 =
|
||
new_sub_parser_from_file(self.sess, &path, directory_ownership, Some(name), id_sp);
|
||
p0.cfg_mods = self.cfg_mods;
|
||
let mod_inner_lo = p0.span;
|
||
let mod_attrs = p0.parse_inner_attributes()?;
|
||
let mut m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?;
|
||
m0.inline = false;
|
||
self.sess.included_mod_stack.borrow_mut().pop();
|
||
Ok((m0, mod_attrs))
|
||
}
|
||
|
||
/// Parses a function declaration from a foreign module.
|
||
fn parse_item_foreign_fn(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
|
||
-> PResult<'a, ForeignItem> {
|
||
self.expect_keyword(keywords::Fn)?;
|
||
|
||
let (ident, mut generics) = self.parse_fn_header()?;
|
||
let decl = self.parse_fn_decl(true)?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
let hi = self.span;
|
||
self.expect(&token::Semi)?;
|
||
Ok(ast::ForeignItem {
|
||
ident,
|
||
attrs,
|
||
node: ForeignItemKind::Fn(decl, generics),
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
vis,
|
||
})
|
||
}
|
||
|
||
/// Parses a static item from a foreign module.
|
||
/// Assumes that the `static` keyword is already parsed.
|
||
fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
|
||
-> PResult<'a, ForeignItem> {
|
||
let mutbl = self.eat_keyword(keywords::Mut);
|
||
let ident = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
let hi = self.span;
|
||
self.expect(&token::Semi)?;
|
||
Ok(ForeignItem {
|
||
ident,
|
||
attrs,
|
||
node: ForeignItemKind::Static(ty, mutbl),
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
vis,
|
||
})
|
||
}
|
||
|
||
/// Parses a type from a foreign module.
|
||
fn parse_item_foreign_type(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
|
||
-> PResult<'a, ForeignItem> {
|
||
self.expect_keyword(keywords::Type)?;
|
||
|
||
let ident = self.parse_ident()?;
|
||
let hi = self.span;
|
||
self.expect(&token::Semi)?;
|
||
Ok(ast::ForeignItem {
|
||
ident: ident,
|
||
attrs: attrs,
|
||
node: ForeignItemKind::Ty,
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
vis: vis
|
||
})
|
||
}
|
||
|
||
fn parse_crate_name_with_dashes(&mut self) -> PResult<'a, ast::Ident> {
|
||
let error_msg = "crate name using dashes are not valid in `extern crate` statements";
|
||
let suggestion_msg = "if the original crate name uses dashes you need to use underscores \
|
||
in the code";
|
||
let mut ident = if self.token.is_keyword(keywords::SelfLower) {
|
||
self.parse_path_segment_ident()
|
||
} else {
|
||
self.parse_ident()
|
||
}?;
|
||
let mut idents = vec![];
|
||
let mut replacement = vec![];
|
||
let mut fixed_crate_name = false;
|
||
// Accept `extern crate name-like-this` for better diagnostics
|
||
let dash = token::Token::BinOp(token::BinOpToken::Minus);
|
||
if self.token == dash { // Do not include `-` as part of the expected tokens list
|
||
while self.eat(&dash) {
|
||
fixed_crate_name = true;
|
||
replacement.push((self.prev_span, "_".to_string()));
|
||
idents.push(self.parse_ident()?);
|
||
}
|
||
}
|
||
if fixed_crate_name {
|
||
let fixed_name_sp = ident.span.to(idents.last().unwrap().span);
|
||
let mut fixed_name = format!("{}", ident.name);
|
||
for part in idents {
|
||
fixed_name.push_str(&format!("_{}", part.name));
|
||
}
|
||
ident = Ident::from_str(&fixed_name).with_span_pos(fixed_name_sp);
|
||
|
||
let mut err = self.struct_span_err(fixed_name_sp, error_msg);
|
||
err.span_label(fixed_name_sp, "dash-separated idents are not valid");
|
||
err.multipart_suggestion(
|
||
suggestion_msg,
|
||
replacement,
|
||
Applicability::MachineApplicable,
|
||
);
|
||
err.emit();
|
||
}
|
||
Ok(ident)
|
||
}
|
||
|
||
/// Parses `extern crate` links.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// extern crate foo;
|
||
/// extern crate bar as foo;
|
||
/// ```
|
||
fn parse_item_extern_crate(&mut self,
|
||
lo: Span,
|
||
visibility: Visibility,
|
||
attrs: Vec<Attribute>)
|
||
-> PResult<'a, P<Item>> {
|
||
// Accept `extern crate name-like-this` for better diagnostics
|
||
let orig_name = self.parse_crate_name_with_dashes()?;
|
||
let (item_name, orig_name) = if let Some(rename) = self.parse_rename()? {
|
||
(rename, Some(orig_name.name))
|
||
} else {
|
||
(orig_name, None)
|
||
};
|
||
self.expect(&token::Semi)?;
|
||
|
||
let span = lo.to(self.prev_span);
|
||
Ok(self.mk_item(span, item_name, ItemKind::ExternCrate(orig_name), visibility, attrs))
|
||
}
|
||
|
||
/// Parses `extern` for foreign ABIs modules.
|
||
///
|
||
/// `extern` is expected to have been
|
||
/// consumed before calling this method.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```ignore (only-for-syntax-highlight)
|
||
/// extern "C" {}
|
||
/// extern {}
|
||
/// ```
|
||
fn parse_item_foreign_mod(&mut self,
|
||
lo: Span,
|
||
opt_abi: Option<Abi>,
|
||
visibility: Visibility,
|
||
mut attrs: Vec<Attribute>)
|
||
-> PResult<'a, P<Item>> {
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
|
||
let abi = opt_abi.unwrap_or(Abi::C);
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
let mut foreign_items = vec![];
|
||
while !self.eat(&token::CloseDelim(token::Brace)) {
|
||
foreign_items.push(self.parse_foreign_item()?);
|
||
}
|
||
|
||
let prev_span = self.prev_span;
|
||
let m = ast::ForeignMod {
|
||
abi,
|
||
items: foreign_items
|
||
};
|
||
let invalid = keywords::Invalid.ident();
|
||
Ok(self.mk_item(lo.to(prev_span), invalid, ItemKind::ForeignMod(m), visibility, attrs))
|
||
}
|
||
|
||
/// Parses `type Foo = Bar;`
|
||
/// or
|
||
/// `existential type Foo: Bar;`
|
||
/// or
|
||
/// `return `None``
|
||
/// without modifying the parser state.
|
||
fn eat_type(&mut self) -> Option<PResult<'a, (Ident, AliasKind, ast::Generics)>> {
|
||
// This parses the grammar:
|
||
// Ident ["<"...">"] ["where" ...] ("=" | ":") Ty ";"
|
||
if self.check_keyword(keywords::Type) ||
|
||
self.check_keyword(keywords::Existential) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Type)) {
|
||
let existential = self.eat_keyword(keywords::Existential);
|
||
assert!(self.eat_keyword(keywords::Type));
|
||
Some(self.parse_existential_or_alias(existential))
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
/// Parses a type alias or existential type.
|
||
fn parse_existential_or_alias(
|
||
&mut self,
|
||
existential: bool,
|
||
) -> PResult<'a, (Ident, AliasKind, ast::Generics)> {
|
||
let ident = self.parse_ident()?;
|
||
let mut tps = self.parse_generics()?;
|
||
tps.where_clause = self.parse_where_clause()?;
|
||
let alias = if existential {
|
||
self.expect(&token::Colon)?;
|
||
let bounds = self.parse_generic_bounds(None)?;
|
||
AliasKind::Existential(bounds)
|
||
} else {
|
||
self.expect(&token::Eq)?;
|
||
let ty = self.parse_ty()?;
|
||
AliasKind::Weak(ty)
|
||
};
|
||
self.expect(&token::Semi)?;
|
||
Ok((ident, alias, tps))
|
||
}
|
||
|
||
/// Parses the part of an enum declaration following the `{`.
|
||
fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> {
|
||
let mut variants = Vec::new();
|
||
let mut all_nullary = true;
|
||
let mut any_disr = vec![];
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
let variant_attrs = self.parse_outer_attributes()?;
|
||
let vlo = self.span;
|
||
|
||
let struct_def;
|
||
let mut disr_expr = None;
|
||
let ident = self.parse_ident()?;
|
||
if self.check(&token::OpenDelim(token::Brace)) {
|
||
// Parse a struct variant.
|
||
all_nullary = false;
|
||
struct_def = VariantData::Struct(self.parse_record_struct_body()?,
|
||
ast::DUMMY_NODE_ID);
|
||
} else if self.check(&token::OpenDelim(token::Paren)) {
|
||
all_nullary = false;
|
||
struct_def = VariantData::Tuple(self.parse_tuple_struct_body()?,
|
||
ast::DUMMY_NODE_ID);
|
||
} else if self.eat(&token::Eq) {
|
||
disr_expr = Some(AnonConst {
|
||
id: ast::DUMMY_NODE_ID,
|
||
value: self.parse_expr()?,
|
||
});
|
||
if let Some(sp) = disr_expr.as_ref().map(|c| c.value.span) {
|
||
any_disr.push(sp);
|
||
}
|
||
struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
|
||
} else {
|
||
struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
|
||
}
|
||
|
||
let vr = ast::Variant_ {
|
||
ident,
|
||
attrs: variant_attrs,
|
||
data: struct_def,
|
||
disr_expr,
|
||
};
|
||
variants.push(respan(vlo.to(self.prev_span), vr));
|
||
|
||
if !self.eat(&token::Comma) { break; }
|
||
}
|
||
self.expect(&token::CloseDelim(token::Brace))?;
|
||
if !any_disr.is_empty() && !all_nullary {
|
||
let mut err =self.struct_span_err(
|
||
any_disr.clone(),
|
||
"discriminator values can only be used with a field-less enum",
|
||
);
|
||
for sp in any_disr {
|
||
err.span_label(sp, "only valid in field-less enums");
|
||
}
|
||
err.emit();
|
||
}
|
||
|
||
Ok(ast::EnumDef { variants })
|
||
}
|
||
|
||
/// Parses an enum declaration.
|
||
fn parse_item_enum(&mut self) -> PResult<'a, ItemInfo> {
|
||
let id = self.parse_ident()?;
|
||
let mut generics = self.parse_generics()?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
|
||
let enum_definition = self.parse_enum_def(&generics).map_err(|e| {
|
||
self.recover_stmt();
|
||
self.eat(&token::CloseDelim(token::Brace));
|
||
e
|
||
})?;
|
||
Ok((id, ItemKind::Enum(enum_definition, generics), None))
|
||
}
|
||
|
||
/// Parses a string as an ABI spec on an extern type or module. Consumes
|
||
/// the `extern` keyword, if one is found.
|
||
fn parse_opt_abi(&mut self) -> PResult<'a, Option<Abi>> {
|
||
match self.token {
|
||
token::Literal(token::Str_(s), suf) | token::Literal(token::StrRaw(s, _), suf) => {
|
||
let sp = self.span;
|
||
self.expect_no_suffix(sp, "ABI spec", suf);
|
||
self.bump();
|
||
match abi::lookup(&s.as_str()) {
|
||
Some(abi) => Ok(Some(abi)),
|
||
None => {
|
||
let prev_span = self.prev_span;
|
||
let mut err = struct_span_err!(
|
||
self.sess.span_diagnostic,
|
||
prev_span,
|
||
E0703,
|
||
"invalid ABI: found `{}`",
|
||
s);
|
||
err.span_label(prev_span, "invalid ABI");
|
||
err.help(&format!("valid ABIs: {}", abi::all_names().join(", ")));
|
||
err.emit();
|
||
Ok(None)
|
||
}
|
||
}
|
||
}
|
||
|
||
_ => Ok(None),
|
||
}
|
||
}
|
||
|
||
fn is_static_global(&mut self) -> bool {
|
||
if self.check_keyword(keywords::Static) {
|
||
// Check if this could be a closure
|
||
!self.look_ahead(1, |token| {
|
||
if token.is_keyword(keywords::Move) {
|
||
return true;
|
||
}
|
||
match *token {
|
||
token::BinOp(token::Or) | token::OrOr => true,
|
||
_ => false,
|
||
}
|
||
})
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
fn parse_item_(
|
||
&mut self,
|
||
attrs: Vec<Attribute>,
|
||
macros_allowed: bool,
|
||
attributes_allowed: bool,
|
||
) -> PResult<'a, Option<P<Item>>> {
|
||
let (ret, tokens) = self.collect_tokens(|this| {
|
||
this.parse_item_implementation(attrs, macros_allowed, attributes_allowed)
|
||
})?;
|
||
|
||
// Once we've parsed an item and recorded the tokens we got while
|
||
// parsing we may want to store `tokens` into the item we're about to
|
||
// return. Note, though, that we specifically didn't capture tokens
|
||
// related to outer attributes. The `tokens` field here may later be
|
||
// used with procedural macros to convert this item back into a token
|
||
// stream, but during expansion we may be removing attributes as we go
|
||
// along.
|
||
//
|
||
// If we've got inner attributes then the `tokens` we've got above holds
|
||
// these inner attributes. If an inner attribute is expanded we won't
|
||
// actually remove it from the token stream, so we'll just keep yielding
|
||
// it (bad!). To work around this case for now we just avoid recording
|
||
// `tokens` if we detect any inner attributes. This should help keep
|
||
// expansion correct, but we should fix this bug one day!
|
||
Ok(ret.map(|item| {
|
||
item.map(|mut i| {
|
||
if !i.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
|
||
i.tokens = Some(tokens);
|
||
}
|
||
i
|
||
})
|
||
}))
|
||
}
|
||
|
||
/// Parses one of the items allowed by the flags.
|
||
fn parse_item_implementation(
|
||
&mut self,
|
||
attrs: Vec<Attribute>,
|
||
macros_allowed: bool,
|
||
attributes_allowed: bool,
|
||
) -> PResult<'a, Option<P<Item>>> {
|
||
maybe_whole!(self, NtItem, |item| {
|
||
let mut item = item.into_inner();
|
||
let mut attrs = attrs;
|
||
mem::swap(&mut item.attrs, &mut attrs);
|
||
item.attrs.extend(attrs);
|
||
Some(P(item))
|
||
});
|
||
|
||
let lo = self.span;
|
||
|
||
let visibility = self.parse_visibility(false)?;
|
||
|
||
if self.eat_keyword(keywords::Use) {
|
||
// USE ITEM
|
||
let item_ = ItemKind::Use(P(self.parse_use_tree()?));
|
||
self.expect(&token::Semi)?;
|
||
|
||
let span = lo.to(self.prev_span);
|
||
let item = self.mk_item(span, keywords::Invalid.ident(), item_, visibility, attrs);
|
||
return Ok(Some(item));
|
||
}
|
||
|
||
if self.eat_keyword(keywords::Extern) {
|
||
if self.eat_keyword(keywords::Crate) {
|
||
return Ok(Some(self.parse_item_extern_crate(lo, visibility, attrs)?));
|
||
}
|
||
|
||
let opt_abi = self.parse_opt_abi()?;
|
||
|
||
if self.eat_keyword(keywords::Fn) {
|
||
// EXTERN FUNCTION ITEM
|
||
let fn_span = self.prev_span;
|
||
let abi = opt_abi.unwrap_or(Abi::C);
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(Unsafety::Normal,
|
||
IsAsync::NotAsync,
|
||
respan(fn_span, Constness::NotConst),
|
||
abi)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
} else if self.check(&token::OpenDelim(token::Brace)) {
|
||
return Ok(Some(self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs)?));
|
||
}
|
||
|
||
self.unexpected()?;
|
||
}
|
||
|
||
if self.is_static_global() {
|
||
self.bump();
|
||
// STATIC ITEM
|
||
let m = if self.eat_keyword(keywords::Mut) {
|
||
Mutability::Mutable
|
||
} else {
|
||
Mutability::Immutable
|
||
};
|
||
let (ident, item_, extra_attrs) = self.parse_item_const(Some(m))?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Const) {
|
||
let const_span = self.prev_span;
|
||
if self.check_keyword(keywords::Fn)
|
||
|| (self.check_keyword(keywords::Unsafe)
|
||
&& self.look_ahead(1, |t| t.is_keyword(keywords::Fn))) {
|
||
// CONST FUNCTION ITEM
|
||
let unsafety = self.parse_unsafety();
|
||
self.bump();
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(unsafety,
|
||
IsAsync::NotAsync,
|
||
respan(const_span, Constness::Const),
|
||
Abi::Rust)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
|
||
// CONST ITEM
|
||
if self.eat_keyword(keywords::Mut) {
|
||
let prev_span = self.prev_span;
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(prev_span, "const globals cannot be mutable");
|
||
err.span_label(prev_span, "cannot be mutable");
|
||
err.span_suggestion(
|
||
const_span,
|
||
"you might want to declare a static instead",
|
||
"static".to_owned(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
err.emit();
|
||
}
|
||
let (ident, item_, extra_attrs) = self.parse_item_const(None)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
|
||
// `unsafe async fn` or `async fn`
|
||
if (
|
||
self.check_keyword(keywords::Unsafe) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Async))
|
||
) || (
|
||
self.check_keyword(keywords::Async) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Fn))
|
||
)
|
||
{
|
||
// ASYNC FUNCTION ITEM
|
||
let unsafety = self.parse_unsafety();
|
||
self.expect_keyword(keywords::Async)?;
|
||
self.expect_keyword(keywords::Fn)?;
|
||
let fn_span = self.prev_span;
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(unsafety,
|
||
IsAsync::Async {
|
||
closure_id: ast::DUMMY_NODE_ID,
|
||
return_impl_trait_id: ast::DUMMY_NODE_ID,
|
||
},
|
||
respan(fn_span, Constness::NotConst),
|
||
Abi::Rust)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.check_keyword(keywords::Unsafe) &&
|
||
(self.look_ahead(1, |t| t.is_keyword(keywords::Trait)) ||
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Auto)))
|
||
{
|
||
// UNSAFE TRAIT ITEM
|
||
self.bump(); // `unsafe`
|
||
let is_auto = if self.eat_keyword(keywords::Trait) {
|
||
IsAuto::No
|
||
} else {
|
||
self.expect_keyword(keywords::Auto)?;
|
||
self.expect_keyword(keywords::Trait)?;
|
||
IsAuto::Yes
|
||
};
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_trait(is_auto, Unsafety::Unsafe)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.check_keyword(keywords::Impl) ||
|
||
self.check_keyword(keywords::Unsafe) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Impl)) ||
|
||
self.check_keyword(keywords::Default) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Impl)) ||
|
||
self.check_keyword(keywords::Default) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Unsafe)) {
|
||
// IMPL ITEM
|
||
let defaultness = self.parse_defaultness();
|
||
let unsafety = self.parse_unsafety();
|
||
self.expect_keyword(keywords::Impl)?;
|
||
let (ident, item, extra_attrs) = self.parse_item_impl(unsafety, defaultness)?;
|
||
let span = lo.to(self.prev_span);
|
||
return Ok(Some(self.mk_item(span, ident, item, visibility,
|
||
maybe_append(attrs, extra_attrs))));
|
||
}
|
||
if self.check_keyword(keywords::Fn) {
|
||
// FUNCTION ITEM
|
||
self.bump();
|
||
let fn_span = self.prev_span;
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(Unsafety::Normal,
|
||
IsAsync::NotAsync,
|
||
respan(fn_span, Constness::NotConst),
|
||
Abi::Rust)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.check_keyword(keywords::Unsafe)
|
||
&& self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) {
|
||
// UNSAFE FUNCTION ITEM
|
||
self.bump(); // `unsafe`
|
||
// `{` is also expected after `unsafe`, in case of error, include it in the diagnostic
|
||
self.check(&token::OpenDelim(token::Brace));
|
||
let abi = if self.eat_keyword(keywords::Extern) {
|
||
self.parse_opt_abi()?.unwrap_or(Abi::C)
|
||
} else {
|
||
Abi::Rust
|
||
};
|
||
self.expect_keyword(keywords::Fn)?;
|
||
let fn_span = self.prev_span;
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(Unsafety::Unsafe,
|
||
IsAsync::NotAsync,
|
||
respan(fn_span, Constness::NotConst),
|
||
abi)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Mod) {
|
||
// MODULE ITEM
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_mod(&attrs[..])?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if let Some(type_) = self.eat_type() {
|
||
let (ident, alias, generics) = type_?;
|
||
// TYPE ITEM
|
||
let item_ = match alias {
|
||
AliasKind::Weak(ty) => ItemKind::Ty(ty, generics),
|
||
AliasKind::Existential(bounds) => ItemKind::Existential(bounds, generics),
|
||
};
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
attrs);
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Enum) {
|
||
// ENUM ITEM
|
||
let (ident, item_, extra_attrs) = self.parse_item_enum()?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.check_keyword(keywords::Trait)
|
||
|| (self.check_keyword(keywords::Auto)
|
||
&& self.look_ahead(1, |t| t.is_keyword(keywords::Trait)))
|
||
{
|
||
let is_auto = if self.eat_keyword(keywords::Trait) {
|
||
IsAuto::No
|
||
} else {
|
||
self.expect_keyword(keywords::Auto)?;
|
||
self.expect_keyword(keywords::Trait)?;
|
||
IsAuto::Yes
|
||
};
|
||
// TRAIT ITEM
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_trait(is_auto, Unsafety::Normal)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Struct) {
|
||
// STRUCT ITEM
|
||
let (ident, item_, extra_attrs) = self.parse_item_struct()?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.is_union_item() {
|
||
// UNION ITEM
|
||
self.bump();
|
||
let (ident, item_, extra_attrs) = self.parse_item_union()?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if let Some(macro_def) = self.eat_macro_def(&attrs, &visibility, lo)? {
|
||
return Ok(Some(macro_def));
|
||
}
|
||
|
||
// Verify whether we have encountered a struct or method definition where the user forgot to
|
||
// add the `struct` or `fn` keyword after writing `pub`: `pub S {}`
|
||
if visibility.node.is_pub() &&
|
||
self.check_ident() &&
|
||
self.look_ahead(1, |t| *t != token::Not)
|
||
{
|
||
// Space between `pub` keyword and the identifier
|
||
//
|
||
// pub S {}
|
||
// ^^^ `sp` points here
|
||
let sp = self.prev_span.between(self.span);
|
||
let full_sp = self.prev_span.to(self.span);
|
||
let ident_sp = self.span;
|
||
if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) {
|
||
// possible public struct definition where `struct` was forgotten
|
||
let ident = self.parse_ident().unwrap();
|
||
let msg = format!("add `struct` here to parse `{}` as a public struct",
|
||
ident);
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "missing `struct` for struct definition");
|
||
err.span_suggestion_short(
|
||
sp, &msg, " struct ".into(), Applicability::MaybeIncorrect // speculative
|
||
);
|
||
return Err(err);
|
||
} else if self.look_ahead(1, |t| *t == token::OpenDelim(token::Paren)) {
|
||
let ident = self.parse_ident().unwrap();
|
||
self.bump(); // `(`
|
||
let kw_name = if let Ok(Some(_)) = self.parse_self_arg() {
|
||
"method"
|
||
} else {
|
||
"function"
|
||
};
|
||
self.consume_block(token::Paren);
|
||
let (kw, kw_name, ambiguous) = if self.check(&token::RArrow) {
|
||
self.eat_to_tokens(&[&token::OpenDelim(token::Brace)]);
|
||
self.bump(); // `{`
|
||
("fn", kw_name, false)
|
||
} else if self.check(&token::OpenDelim(token::Brace)) {
|
||
self.bump(); // `{`
|
||
("fn", kw_name, false)
|
||
} else if self.check(&token::Colon) {
|
||
let kw = "struct";
|
||
(kw, kw, false)
|
||
} else {
|
||
("fn` or `struct", "function or struct", true)
|
||
};
|
||
self.consume_block(token::Brace);
|
||
|
||
let msg = format!("missing `{}` for {} definition", kw, kw_name);
|
||
let mut err = self.diagnostic().struct_span_err(sp, &msg);
|
||
if !ambiguous {
|
||
let suggestion = format!("add `{}` here to parse `{}` as a public {}",
|
||
kw,
|
||
ident,
|
||
kw_name);
|
||
err.span_suggestion_short(
|
||
sp, &suggestion, format!(" {} ", kw), Applicability::MachineApplicable
|
||
);
|
||
} else {
|
||
if let Ok(snippet) = self.sess.source_map().span_to_snippet(ident_sp) {
|
||
err.span_suggestion(
|
||
full_sp,
|
||
"if you meant to call a macro, try",
|
||
format!("{}!", snippet),
|
||
// this is the `ambiguous` conditional branch
|
||
Applicability::MaybeIncorrect
|
||
);
|
||
} else {
|
||
err.help("if you meant to call a macro, remove the `pub` \
|
||
and add a trailing `!` after the identifier");
|
||
}
|
||
}
|
||
return Err(err);
|
||
} else if self.look_ahead(1, |t| *t == token::Lt) {
|
||
let ident = self.parse_ident().unwrap();
|
||
self.eat_to_tokens(&[&token::Gt]);
|
||
self.bump(); // `>`
|
||
let (kw, kw_name, ambiguous) = if self.eat(&token::OpenDelim(token::Paren)) {
|
||
if let Ok(Some(_)) = self.parse_self_arg() {
|
||
("fn", "method", false)
|
||
} else {
|
||
("fn", "function", false)
|
||
}
|
||
} else if self.check(&token::OpenDelim(token::Brace)) {
|
||
("struct", "struct", false)
|
||
} else {
|
||
("fn` or `struct", "function or struct", true)
|
||
};
|
||
let msg = format!("missing `{}` for {} definition", kw, kw_name);
|
||
let mut err = self.diagnostic().struct_span_err(sp, &msg);
|
||
if !ambiguous {
|
||
err.span_suggestion_short(
|
||
sp,
|
||
&format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name),
|
||
format!(" {} ", kw),
|
||
Applicability::MachineApplicable,
|
||
);
|
||
}
|
||
return Err(err);
|
||
}
|
||
}
|
||
self.parse_macro_use_or_failure(attrs, macros_allowed, attributes_allowed, lo, visibility)
|
||
}
|
||
|
||
/// Parses a foreign item.
|
||
crate fn parse_foreign_item(&mut self) -> PResult<'a, ForeignItem> {
|
||
maybe_whole!(self, NtForeignItem, |ni| ni);
|
||
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
let visibility = self.parse_visibility(false)?;
|
||
|
||
// FOREIGN STATIC ITEM
|
||
// Treat `const` as `static` for error recovery, but don't add it to expected tokens.
|
||
if self.check_keyword(keywords::Static) || self.token.is_keyword(keywords::Const) {
|
||
if self.token.is_keyword(keywords::Const) {
|
||
self.diagnostic()
|
||
.struct_span_err(self.span, "extern items cannot be `const`")
|
||
.span_suggestion(
|
||
self.span,
|
||
"try using a static value",
|
||
"static".to_owned(),
|
||
Applicability::MachineApplicable
|
||
).emit();
|
||
}
|
||
self.bump(); // `static` or `const`
|
||
return Ok(self.parse_item_foreign_static(visibility, lo, attrs)?);
|
||
}
|
||
// FOREIGN FUNCTION ITEM
|
||
if self.check_keyword(keywords::Fn) {
|
||
return Ok(self.parse_item_foreign_fn(visibility, lo, attrs)?);
|
||
}
|
||
// FOREIGN TYPE ITEM
|
||
if self.check_keyword(keywords::Type) {
|
||
return Ok(self.parse_item_foreign_type(visibility, lo, attrs)?);
|
||
}
|
||
|
||
match self.parse_assoc_macro_invoc("extern", Some(&visibility), &mut false)? {
|
||
Some(mac) => {
|
||
Ok(
|
||
ForeignItem {
|
||
ident: keywords::Invalid.ident(),
|
||
span: lo.to(self.prev_span),
|
||
id: ast::DUMMY_NODE_ID,
|
||
attrs,
|
||
vis: visibility,
|
||
node: ForeignItemKind::Macro(mac),
|
||
}
|
||
)
|
||
}
|
||
None => {
|
||
if !attrs.is_empty() {
|
||
self.expected_item_err(&attrs)?;
|
||
}
|
||
|
||
self.unexpected()
|
||
}
|
||
}
|
||
}
|
||
|
||
/// This is the fall-through for parsing items.
|
||
fn parse_macro_use_or_failure(
|
||
&mut self,
|
||
attrs: Vec<Attribute> ,
|
||
macros_allowed: bool,
|
||
attributes_allowed: bool,
|
||
lo: Span,
|
||
visibility: Visibility
|
||
) -> PResult<'a, Option<P<Item>>> {
|
||
if macros_allowed && self.token.is_path_start() {
|
||
// MACRO INVOCATION ITEM
|
||
|
||
let prev_span = self.prev_span;
|
||
self.complain_if_pub_macro(&visibility.node, prev_span);
|
||
|
||
let mac_lo = self.span;
|
||
|
||
// item macro.
|
||
let pth = self.parse_path(PathStyle::Mod)?;
|
||
self.expect(&token::Not)?;
|
||
|
||
// a 'special' identifier (like what `macro_rules!` uses)
|
||
// is optional. We should eventually unify invoc syntax
|
||
// and remove this.
|
||
let id = if self.token.is_ident() {
|
||
self.parse_ident()?
|
||
} else {
|
||
keywords::Invalid.ident() // no special identifier
|
||
};
|
||
// eat a matched-delimiter token tree:
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
if delim != MacDelimiter::Brace {
|
||
if !self.eat(&token::Semi) {
|
||
self.span_err(self.prev_span,
|
||
"macros that expand to items must either \
|
||
be surrounded with braces or followed by \
|
||
a semicolon");
|
||
}
|
||
}
|
||
|
||
let hi = self.prev_span;
|
||
let mac = respan(mac_lo.to(hi), Mac_ { path: pth, tts, delim });
|
||
let item = self.mk_item(lo.to(hi), id, ItemKind::Mac(mac), visibility, attrs);
|
||
return Ok(Some(item));
|
||
}
|
||
|
||
// FAILURE TO PARSE ITEM
|
||
match visibility.node {
|
||
VisibilityKind::Inherited => {}
|
||
_ => {
|
||
return Err(self.span_fatal(self.prev_span, "unmatched visibility `pub`"));
|
||
}
|
||
}
|
||
|
||
if !attributes_allowed && !attrs.is_empty() {
|
||
self.expected_item_err(&attrs)?;
|
||
}
|
||
Ok(None)
|
||
}
|
||
|
||
/// Parses a macro invocation inside a `trait`, `impl` or `extern` block.
|
||
fn parse_assoc_macro_invoc(&mut self, item_kind: &str, vis: Option<&Visibility>,
|
||
at_end: &mut bool) -> PResult<'a, Option<Mac>>
|
||
{
|
||
if self.token.is_path_start() {
|
||
let prev_span = self.prev_span;
|
||
let lo = self.span;
|
||
let pth = self.parse_path(PathStyle::Mod)?;
|
||
|
||
if pth.segments.len() == 1 {
|
||
if !self.eat(&token::Not) {
|
||
return Err(self.missing_assoc_item_kind_err(item_kind, prev_span));
|
||
}
|
||
} else {
|
||
self.expect(&token::Not)?;
|
||
}
|
||
|
||
if let Some(vis) = vis {
|
||
self.complain_if_pub_macro(&vis.node, prev_span);
|
||
}
|
||
|
||
*at_end = true;
|
||
|
||
// eat a matched-delimiter token tree:
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
if delim != MacDelimiter::Brace {
|
||
self.expect(&token::Semi)?;
|
||
}
|
||
|
||
Ok(Some(respan(lo.to(self.prev_span), Mac_ { path: pth, tts, delim })))
|
||
} else {
|
||
Ok(None)
|
||
}
|
||
}
|
||
|
||
fn collect_tokens<F, R>(&mut self, f: F) -> PResult<'a, (R, TokenStream)>
|
||
where F: FnOnce(&mut Self) -> PResult<'a, R>
|
||
{
|
||
// Record all tokens we parse when parsing this item.
|
||
let mut tokens = Vec::new();
|
||
let prev_collecting = match self.token_cursor.frame.last_token {
|
||
LastToken::Collecting(ref mut list) => {
|
||
Some(mem::replace(list, Vec::new()))
|
||
}
|
||
LastToken::Was(ref mut last) => {
|
||
tokens.extend(last.take());
|
||
None
|
||
}
|
||
};
|
||
self.token_cursor.frame.last_token = LastToken::Collecting(tokens);
|
||
let prev = self.token_cursor.stack.len();
|
||
let ret = f(self);
|
||
let last_token = if self.token_cursor.stack.len() == prev {
|
||
&mut self.token_cursor.frame.last_token
|
||
} else {
|
||
&mut self.token_cursor.stack[prev].last_token
|
||
};
|
||
|
||
// Pull out the tokens that we've collected from the call to `f` above.
|
||
let mut collected_tokens = match *last_token {
|
||
LastToken::Collecting(ref mut v) => mem::replace(v, Vec::new()),
|
||
LastToken::Was(_) => panic!("our vector went away?"),
|
||
};
|
||
|
||
// If we're not at EOF our current token wasn't actually consumed by
|
||
// `f`, but it'll still be in our list that we pulled out. In that case
|
||
// put it back.
|
||
let extra_token = if self.token != token::Eof {
|
||
collected_tokens.pop()
|
||
} else {
|
||
None
|
||
};
|
||
|
||
// If we were previously collecting tokens, then this was a recursive
|
||
// call. In that case we need to record all the tokens we collected in
|
||
// our parent list as well. To do that we push a clone of our stream
|
||
// onto the previous list.
|
||
match prev_collecting {
|
||
Some(mut list) => {
|
||
list.extend(collected_tokens.iter().cloned());
|
||
list.extend(extra_token);
|
||
*last_token = LastToken::Collecting(list);
|
||
}
|
||
None => {
|
||
*last_token = LastToken::Was(extra_token);
|
||
}
|
||
}
|
||
|
||
Ok((ret?, TokenStream::new(collected_tokens)))
|
||
}
|
||
|
||
pub fn parse_item(&mut self) -> PResult<'a, Option<P<Item>>> {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
self.parse_item_(attrs, true, false)
|
||
}
|
||
|
||
/// `::{` or `::*`
|
||
fn is_import_coupler(&mut self) -> bool {
|
||
self.check(&token::ModSep) &&
|
||
self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace) ||
|
||
*t == token::BinOp(token::Star))
|
||
}
|
||
|
||
/// Parses a `UseTree`.
|
||
///
|
||
/// ```
|
||
/// USE_TREE = [`::`] `*` |
|
||
/// [`::`] `{` USE_TREE_LIST `}` |
|
||
/// PATH `::` `*` |
|
||
/// PATH `::` `{` USE_TREE_LIST `}` |
|
||
/// PATH [`as` IDENT]
|
||
/// ```
|
||
fn parse_use_tree(&mut self) -> PResult<'a, UseTree> {
|
||
let lo = self.span;
|
||
|
||
let mut prefix = ast::Path { segments: Vec::new(), span: lo.shrink_to_lo() };
|
||
let kind = if self.check(&token::OpenDelim(token::Brace)) ||
|
||
self.check(&token::BinOp(token::Star)) ||
|
||
self.is_import_coupler() {
|
||
// `use *;` or `use ::*;` or `use {...};` or `use ::{...};`
|
||
let mod_sep_ctxt = self.span.ctxt();
|
||
if self.eat(&token::ModSep) {
|
||
prefix.segments.push(
|
||
PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt))
|
||
);
|
||
}
|
||
|
||
if self.eat(&token::BinOp(token::Star)) {
|
||
UseTreeKind::Glob
|
||
} else {
|
||
UseTreeKind::Nested(self.parse_use_tree_list()?)
|
||
}
|
||
} else {
|
||
// `use path::*;` or `use path::{...};` or `use path;` or `use path as bar;`
|
||
prefix = self.parse_path(PathStyle::Mod)?;
|
||
|
||
if self.eat(&token::ModSep) {
|
||
if self.eat(&token::BinOp(token::Star)) {
|
||
UseTreeKind::Glob
|
||
} else {
|
||
UseTreeKind::Nested(self.parse_use_tree_list()?)
|
||
}
|
||
} else {
|
||
UseTreeKind::Simple(self.parse_rename()?, ast::DUMMY_NODE_ID, ast::DUMMY_NODE_ID)
|
||
}
|
||
};
|
||
|
||
Ok(UseTree { prefix, kind, span: lo.to(self.prev_span) })
|
||
}
|
||
|
||
/// Parses a `UseTreeKind::Nested(list)`.
|
||
///
|
||
/// ```
|
||
/// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`]
|
||
/// ```
|
||
fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> {
|
||
self.parse_unspanned_seq(&token::OpenDelim(token::Brace),
|
||
&token::CloseDelim(token::Brace),
|
||
SeqSep::trailing_allowed(token::Comma), |this| {
|
||
Ok((this.parse_use_tree()?, ast::DUMMY_NODE_ID))
|
||
})
|
||
}
|
||
|
||
fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
|
||
if self.eat_keyword(keywords::As) {
|
||
self.parse_ident_or_underscore().map(Some)
|
||
} else {
|
||
Ok(None)
|
||
}
|
||
}
|
||
|
||
/// Parses a source module as a crate. This is the main entry point for the parser.
|
||
pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> {
|
||
let lo = self.span;
|
||
let krate = Ok(ast::Crate {
|
||
attrs: self.parse_inner_attributes()?,
|
||
module: self.parse_mod_items(&token::Eof, lo)?,
|
||
span: lo.to(self.span),
|
||
});
|
||
emit_unclosed_delims(&self.unclosed_delims, self.diagnostic());
|
||
self.unclosed_delims.clear();
|
||
krate
|
||
}
|
||
|
||
pub fn parse_optional_str(&mut self) -> Option<(Symbol, ast::StrStyle, Option<ast::Name>)> {
|
||
let ret = match self.token {
|
||
token::Literal(token::Str_(s), suf) => (s, ast::StrStyle::Cooked, suf),
|
||
token::Literal(token::StrRaw(s, n), suf) => (s, ast::StrStyle::Raw(n), suf),
|
||
_ => return None
|
||
};
|
||
self.bump();
|
||
Some(ret)
|
||
}
|
||
|
||
pub fn parse_str(&mut self) -> PResult<'a, (Symbol, StrStyle)> {
|
||
match self.parse_optional_str() {
|
||
Some((s, style, suf)) => {
|
||
let sp = self.prev_span;
|
||
self.expect_no_suffix(sp, "string literal", suf);
|
||
Ok((s, style))
|
||
}
|
||
_ => {
|
||
let msg = "expected string literal";
|
||
let mut err = self.fatal(msg);
|
||
err.span_label(self.span, msg);
|
||
Err(err)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
pub fn emit_unclosed_delims(unclosed_delims: &[UnmatchedBrace], handler: &errors::Handler) {
|
||
for unmatched in unclosed_delims {
|
||
let mut err = handler.struct_span_err(unmatched.found_span, &format!(
|
||
"incorrect close delimiter: `{}`",
|
||
pprust::token_to_string(&token::Token::CloseDelim(unmatched.found_delim)),
|
||
));
|
||
err.span_label(unmatched.found_span, "incorrect close delimiter");
|
||
if let Some(sp) = unmatched.candidate_span {
|
||
err.span_label(sp, "close delimiter possibly meant for this");
|
||
}
|
||
if let Some(sp) = unmatched.unclosed_span {
|
||
err.span_label(sp, "un-closed delimiter");
|
||
}
|
||
err.emit();
|
||
}
|
||
}
|