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rust-clippy/clippy_utils/src/lib.rs

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#![feature(box_patterns)]
#![feature(in_band_lifetimes)]
#![feature(or_patterns)]
#![feature(rustc_private)]
#![recursion_limit = "512"]
#![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
// FIXME: switch to something more ergonomic here, once available.
// (Currently there is no way to opt into sysroot crates without `extern crate`.)
extern crate rustc_ast;
extern crate rustc_ast_pretty;
extern crate rustc_data_structures;
extern crate rustc_errors;
extern crate rustc_hir;
extern crate rustc_infer;
extern crate rustc_lexer;
extern crate rustc_lint;
extern crate rustc_middle;
extern crate rustc_mir;
extern crate rustc_session;
extern crate rustc_span;
extern crate rustc_target;
extern crate rustc_trait_selection;
extern crate rustc_typeck;
#[macro_use]
pub mod sym_helper;
#[allow(clippy::module_name_repetitions)]
pub mod ast_utils;
pub mod attrs;
pub mod camel_case;
pub mod comparisons;
pub mod consts;
mod diagnostics;
pub mod eager_or_lazy;
pub mod higher;
mod hir_utils;
pub mod numeric_literal;
pub mod paths;
pub mod ptr;
pub mod qualify_min_const_fn;
pub mod sugg;
pub mod usage;
pub mod visitors;
pub use self::attrs::*;
pub use self::diagnostics::*;
pub use self::hir_utils::{both, eq_expr_value, over, SpanlessEq, SpanlessHash};
use std::borrow::Cow;
use std::collections::hash_map::Entry;
use std::hash::BuildHasherDefault;
use if_chain::if_chain;
use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind, Mutability};
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
use rustc_hir::Node;
use rustc_hir::{
def, Arm, Block, Body, Constness, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl, ImplItem, ImplItemKind, Item,
ItemKind, LangItem, MatchSource, Param, Pat, PatKind, Path, PathSegment, QPath, TraitItem, TraitItemKind, TraitRef,
TyKind, Unsafety,
};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_lint::{LateContext, Level, Lint, LintContext};
use rustc_middle::hir::exports::Export;
use rustc_middle::hir::map::Map;
use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
use rustc_middle::ty::{self, layout::IntegerExt, DefIdTree, IntTy, Ty, TyCtxt, TypeFoldable, UintTy};
use rustc_semver::RustcVersion;
use rustc_session::Session;
use rustc_span::hygiene::{self, ExpnKind, MacroKind};
use rustc_span::source_map::original_sp;
use rustc_span::sym;
use rustc_span::symbol::{kw, Symbol};
use rustc_span::{BytePos, Pos, Span, SyntaxContext, DUMMY_SP};
use rustc_target::abi::Integer;
use rustc_trait_selection::traits::query::normalize::AtExt;
use smallvec::SmallVec;
use crate::consts::{constant, Constant};
use std::collections::HashMap;
pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
if let Ok(version) = RustcVersion::parse(msrv) {
return Some(version);
} else if let Some(sess) = sess {
if let Some(span) = span {
sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
}
}
None
}
pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
}
#[macro_export]
macro_rules! extract_msrv_attr {
(LateContext) => {
extract_msrv_attr!(@LateContext, ());
};
(EarlyContext) => {
extract_msrv_attr!(@EarlyContext);
};
(@$context:ident$(, $call:tt)?) => {
fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
use $crate::get_unique_inner_attr;
match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
Some(msrv_attr) => {
if let Some(msrv) = msrv_attr.value_str() {
self.msrv = $crate::parse_msrv(
&msrv.to_string(),
Some(cx.sess$($call)?),
Some(msrv_attr.span),
);
} else {
cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
}
},
_ => (),
}
}
};
}
/// Returns `true` if the two spans come from differing expansions (i.e., one is
/// from a macro and one isn't).
#[must_use]
pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
rhs.ctxt() != lhs.ctxt()
}
/// Returns `true` if the given `NodeId` is inside a constant context
///
/// # Example
///
/// ```rust,ignore
/// if in_constant(cx, expr.hir_id) {
/// // Do something
/// }
/// ```
pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
let parent_id = cx.tcx.hir().get_parent_item(id);
match cx.tcx.hir().get(parent_id) {
Node::Item(&Item {
kind: ItemKind::Const(..) | ItemKind::Static(..),
..
})
| Node::TraitItem(&TraitItem {
kind: TraitItemKind::Const(..),
..
})
| Node::ImplItem(&ImplItem {
kind: ImplItemKind::Const(..),
..
})
| Node::AnonConst(_) => true,
Node::Item(&Item {
kind: ItemKind::Fn(ref sig, ..),
..
})
| Node::ImplItem(&ImplItem {
kind: ImplItemKind::Fn(ref sig, _),
..
}) => sig.header.constness == Constness::Const,
_ => false,
}
}
/// Returns `true` if this `span` was expanded by any macro.
#[must_use]
pub fn in_macro(span: Span) -> bool {
if span.from_expansion() {
!matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
} else {
false
}
}
// If the snippet is empty, it's an attribute that was inserted during macro
// expansion and we want to ignore those, because they could come from external
// sources that the user has no control over.
// For some reason these attributes don't have any expansion info on them, so
// we have to check it this way until there is a better way.
pub fn is_present_in_source<T: LintContext>(cx: &T, span: Span) -> bool {
if let Some(snippet) = snippet_opt(cx, span) {
if snippet.is_empty() {
return false;
}
}
true
}
/// Checks if given pattern is a wildcard (`_`)
pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
matches!(pat.kind, PatKind::Wild)
}
/// Checks if type is struct, enum or union type with the given def path.
///
/// If the type is a diagnostic item, use `is_type_diagnostic_item` instead.
/// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
pub fn match_type(cx: &LateContext<'_>, ty: Ty<'_>, path: &[&str]) -> bool {
match ty.kind() {
ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
_ => false,
}
}
/// Checks if the type is equal to a diagnostic item
///
/// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
pub fn is_type_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
match ty.kind() {
ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
_ => false,
}
}
/// Checks if the type is equal to a lang item
pub fn is_type_lang_item(cx: &LateContext<'_>, ty: Ty<'_>, lang_item: hir::LangItem) -> bool {
match ty.kind() {
ty::Adt(adt, _) => cx.tcx.lang_items().require(lang_item).unwrap() == adt.did,
_ => false,
}
}
/// Checks if the first type parameter is a lang item.
pub fn is_ty_param_lang_item(cx: &LateContext<'_>, qpath: &QPath<'tcx>, item: LangItem) -> Option<&'tcx hir::Ty<'tcx>> {
let ty = get_qpath_generic_tys(qpath).next()?;
if let TyKind::Path(qpath) = &ty.kind {
cx.qpath_res(qpath, ty.hir_id)
.opt_def_id()
.map_or(false, |id| {
cx.tcx.lang_items().require(item).map_or(false, |lang_id| id == lang_id)
})
.then(|| ty)
} else {
None
}
}
/// Checks if the first type parameter is a diagnostic item.
pub fn is_ty_param_diagnostic_item(
cx: &LateContext<'_>,
qpath: &QPath<'tcx>,
item: Symbol,
) -> Option<&'tcx hir::Ty<'tcx>> {
let ty = get_qpath_generic_tys(qpath).next()?;
if let TyKind::Path(qpath) = &ty.kind {
cx.qpath_res(qpath, ty.hir_id)
.opt_def_id()
.map_or(false, |id| cx.tcx.is_diagnostic_item(item, id))
.then(|| ty)
} else {
None
}
}
/// Return `true` if the passed `typ` is `isize` or `usize`.
pub fn is_isize_or_usize(typ: Ty<'_>) -> bool {
matches!(typ.kind(), ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize))
}
/// Checks if the method call given in `expr` belongs to the given trait.
pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
let trt_id = cx.tcx.trait_of_item(def_id);
trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
}
/// Checks if the method call given in `expr` belongs to a trait or other container with a given
/// diagnostic item
pub fn is_diagnostic_assoc_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
cx.tcx
.opt_associated_item(def_id)
.and_then(|associated_item| match associated_item.container {
ty::TraitContainer(assoc_def_id) => Some(assoc_def_id),
ty::ImplContainer(assoc_def_id) => match cx.tcx.type_of(assoc_def_id).kind() {
ty::Adt(adt, _) => Some(adt.did),
ty::Slice(_) => cx.tcx.get_diagnostic_item(sym::slice), // this isn't perfect but it works
_ => None,
},
})
.map_or(false, |assoc_def_id| cx.tcx.is_diagnostic_item(diag_item, assoc_def_id))
}
/// Checks if an expression references a variable of the given name.
pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
if let [p] = path.segments {
return p.ident.name == var;
}
}
false
}
pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
match *path {
QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
QPath::TypeRelative(_, ref seg) => seg,
QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
}
}
pub fn get_qpath_generics(path: &QPath<'tcx>) -> Option<&'tcx GenericArgs<'tcx>> {
match path {
QPath::Resolved(_, p) => p.segments.last().and_then(|s| s.args),
QPath::TypeRelative(_, s) => s.args,
QPath::LangItem(..) => None,
}
}
pub fn get_qpath_generic_tys(path: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
get_qpath_generics(path)
.map_or([].as_ref(), |a| a.args)
.iter()
.filter_map(|a| {
if let hir::GenericArg::Type(ty) = a {
Some(ty)
} else {
None
}
})
}
pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
match *path {
QPath::Resolved(_, ref path) => path.segments.get(0),
QPath::TypeRelative(_, ref seg) => Some(seg),
QPath::LangItem(..) => None,
}
}
/// Matches a `QPath` against a slice of segment string literals.
///
/// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
/// `rustc_hir::QPath`.
///
/// # Examples
/// ```rust,ignore
/// match_qpath(path, &["std", "rt", "begin_unwind"])
/// ```
pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
match *path {
QPath::Resolved(_, ref path) => match_path(path, segments),
QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
TyKind::Path(ref inner_path) => {
if let [prefix @ .., end] = segments {
if match_qpath(inner_path, prefix) {
return segment.ident.name.as_str() == *end;
}
}
false
},
_ => false,
},
QPath::LangItem(..) => false,
}
}
/// Matches a `Path` against a slice of segment string literals.
///
/// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
/// `rustc_hir::Path`.
///
/// # Examples
///
/// ```rust,ignore
/// if match_path(&trait_ref.path, &paths::HASH) {
/// // This is the `std::hash::Hash` trait.
/// }
///
/// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
/// // This is a `rustc_middle::lint::Lint`.
/// }
/// ```
pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
path.segments
.iter()
.rev()
.zip(segments.iter().rev())
.all(|(a, b)| a.ident.name.as_str() == *b)
}
/// Matches a `Path` against a slice of segment string literals, e.g.
///
/// # Examples
/// ```rust,ignore
/// match_path_ast(path, &["std", "rt", "begin_unwind"])
/// ```
pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
path.segments
.iter()
.rev()
.zip(segments.iter().rev())
.all(|(a, b)| a.ident.name.as_str() == *b)
}
/// If the expression is a path to a local, returns the canonical `HirId` of the local.
pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
if let Res::Local(id) = path.res {
return Some(id);
}
}
None
}
/// Returns true if the expression is a path to a local with the specified `HirId`.
/// Use this function to see if an expression matches a function argument or a match binding.
pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
path_to_local(expr) == Some(id)
}
/// Gets the definition associated to a path.
#[allow(clippy::shadow_unrelated)] // false positive #6563
pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
macro_rules! try_res {
($e:expr) => {
match $e {
Some(e) => e,
None => return Res::Err,
}
};
}
fn item_child_by_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, name: &str) -> Option<&'tcx Export<HirId>> {
tcx.item_children(def_id)
.iter()
.find(|item| item.ident.name.as_str() == name)
}
let (krate, first, path) = match *path {
[krate, first, ref path @ ..] => (krate, first, path),
_ => return Res::Err,
};
let tcx = cx.tcx;
let crates = tcx.crates();
let krate = try_res!(crates.iter().find(|&&num| tcx.crate_name(num).as_str() == krate));
let first = try_res!(item_child_by_name(tcx, krate.as_def_id(), first));
let last = path
.iter()
.copied()
// `get_def_path` seems to generate these empty segments for extern blocks.
// We can just ignore them.
.filter(|segment| !segment.is_empty())
// for each segment, find the child item
.try_fold(first, |item, segment| {
let def_id = item.res.def_id();
if let Some(item) = item_child_by_name(tcx, def_id, segment) {
Some(item)
} else if matches!(item.res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
// it is not a child item so check inherent impl items
tcx.inherent_impls(def_id)
.iter()
.find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
} else {
None
}
});
try_res!(last).res
}
/// Convenience function to get the `DefId` of a trait by path.
/// It could be a trait or trait alias.
pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
match path_to_res(cx, path) {
Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
_ => None,
}
}
/// Checks whether a type implements a trait.
/// See also `get_trait_def_id`.
pub fn implements_trait<'tcx>(
cx: &LateContext<'tcx>,
ty: Ty<'tcx>,
trait_id: DefId,
ty_params: &[GenericArg<'tcx>],
) -> bool {
// Do not check on infer_types to avoid panic in evaluate_obligation.
if ty.has_infer_types() {
return false;
}
let ty = cx.tcx.erase_regions(ty);
if ty.has_escaping_bound_vars() {
return false;
}
let ty_params = cx.tcx.mk_substs(ty_params.iter());
cx.tcx.type_implements_trait((trait_id, ty, ty_params, cx.param_env))
}
/// Gets the `hir::TraitRef` of the trait the given method is implemented for.
///
/// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
///
/// ```rust
/// struct Point(isize, isize);
///
/// impl std::ops::Add for Point {
/// type Output = Self;
///
/// fn add(self, other: Self) -> Self {
/// Point(0, 0)
/// }
/// }
/// ```
pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
// Get the implemented trait for the current function
let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
if_chain! {
if parent_impl != hir::CRATE_HIR_ID;
if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
if let hir::ItemKind::Impl(impl_) = &item.kind;
then { return impl_.of_trait.as_ref(); }
}
None
}
/// Checks whether this type implements `Drop`.
pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
match ty.ty_adt_def() {
Some(def) => def.has_dtor(cx.tcx),
None => false,
}
}
/// Checks whether a type can be partially moved.
pub fn can_partially_move_ty(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
if has_drop(cx, ty) || is_copy(cx, ty) {
return false;
}
match ty.kind() {
ty::Param(_) => false,
ty::Adt(def, subs) => def.all_fields().any(|f| !is_copy(cx, f.ty(cx.tcx, subs))),
_ => true,
}
}
/// Returns the method names and argument list of nested method call expressions that make up
/// `expr`. method/span lists are sorted with the most recent call first.
pub fn method_calls<'tcx>(
expr: &'tcx Expr<'tcx>,
max_depth: usize,
) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
let mut method_names = Vec::with_capacity(max_depth);
let mut arg_lists = Vec::with_capacity(max_depth);
let mut spans = Vec::with_capacity(max_depth);
let mut current = expr;
for _ in 0..max_depth {
if let ExprKind::MethodCall(path, span, args, _) = &current.kind {
if args.iter().any(|e| e.span.from_expansion()) {
break;
}
method_names.push(path.ident.name);
arg_lists.push(&**args);
spans.push(*span);
current = &args[0];
} else {
break;
}
}
(method_names, arg_lists, spans)
}
/// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
///
/// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
/// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
/// containing the `Expr`s for
/// `.bar()` and `.baz()`
pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
let mut current = expr;
let mut matched = Vec::with_capacity(methods.len());
for method_name in methods.iter().rev() {
// method chains are stored last -> first
if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
if path.ident.name.as_str() == *method_name {
if args.iter().any(|e| e.span.from_expansion()) {
return None;
}
matched.push(&**args); // build up `matched` backwards
current = &args[0] // go to parent expression
} else {
return None;
}
} else {
return None;
}
}
// Reverse `matched` so that it is in the same order as `methods`.
matched.reverse();
Some(matched)
}
/// Returns `true` if the provided `def_id` is an entrypoint to a program.
pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
cx.tcx
.entry_fn(LOCAL_CRATE)
.map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
}
/// Returns `true` if the expression is in the program's `#[panic_handler]`.
pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
let parent = cx.tcx.hir().get_parent_item(e.hir_id);
let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
Some(def_id) == cx.tcx.lang_items().panic_impl()
}
/// Gets the name of the item the expression is in, if available.
pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
match cx.tcx.hir().find(parent_id) {
Some(
Node::Item(Item { ident, .. })
| Node::TraitItem(TraitItem { ident, .. })
| Node::ImplItem(ImplItem { ident, .. }),
) => Some(ident.name),
_ => None,
}
}
/// Gets the name of a `Pat`, if any.
pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
match pat.kind {
PatKind::Binding(.., ref spname, _) => Some(spname.name),
PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
_ => None,
}
}
struct ContainsName {
name: Symbol,
result: bool,
}
impl<'tcx> Visitor<'tcx> for ContainsName {
type Map = Map<'tcx>;
fn visit_name(&mut self, _: Span, name: Symbol) {
if self.name == name {
self.result = true;
}
}
fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
NestedVisitorMap::None
}
}
/// Checks if an `Expr` contains a certain name.
pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
let mut cn = ContainsName { name, result: false };
cn.visit_expr(expr);
cn.result
}
/// Returns `true` if `expr` contains a return expression
pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
struct RetCallFinder {
found: bool,
}
impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
type Map = Map<'tcx>;
fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
if self.found {
return;
}
if let hir::ExprKind::Ret(..) = &expr.kind {
self.found = true;
} else {
hir::intravisit::walk_expr(self, expr);
}
}
fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
hir::intravisit::NestedVisitorMap::None
}
}
let mut visitor = RetCallFinder { found: false };
visitor.visit_expr(expr);
visitor.found
}
struct FindMacroCalls<'a, 'b> {
names: &'a [&'b str],
result: Vec<Span>,
}
impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
type Map = Map<'tcx>;
fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
self.result.push(expr.span);
}
// and check sub-expressions
intravisit::walk_expr(self, expr);
}
fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
NestedVisitorMap::None
}
}
/// Finds calls of the specified macros in a function body.
pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
let mut fmc = FindMacroCalls {
names,
result: Vec::new(),
};
fmc.visit_expr(&body.value);
fmc.result
}
/// Converts a span to a code snippet if available, otherwise use default.
///
/// This is useful if you want to provide suggestions for your lint or more generally, if you want
/// to convert a given `Span` to a `str`.
///
/// # Example
/// ```rust,ignore
/// snippet(cx, expr.span, "..")
/// ```
pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
}
/// Same as `snippet`, but it adapts the applicability level by following rules:
///
/// - Applicability level `Unspecified` will never be changed.
/// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
/// - If the default value is used and the applicability level is `MachineApplicable`, change it to
/// `HasPlaceholders`
pub fn snippet_with_applicability<'a, T: LintContext>(
cx: &T,
span: Span,
default: &'a str,
applicability: &mut Applicability,
) -> Cow<'a, str> {
if *applicability != Applicability::Unspecified && span.from_expansion() {
*applicability = Applicability::MaybeIncorrect;
}
snippet_opt(cx, span).map_or_else(
|| {
if *applicability == Applicability::MachineApplicable {
*applicability = Applicability::HasPlaceholders;
}
Cow::Borrowed(default)
},
From::from,
)
}
/// Same as `snippet`, but should only be used when it's clear that the input span is
/// not a macro argument.
pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
snippet(cx, span.source_callsite(), default)
}
/// Converts a span to a code snippet. Returns `None` if not available.
pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
cx.sess().source_map().span_to_snippet(span).ok()
}
/// Converts a span (from a block) to a code snippet if available, otherwise use default.
///
/// This trims the code of indentation, except for the first line. Use it for blocks or block-like
/// things which need to be printed as such.
///
/// The `indent_relative_to` arg can be used, to provide a span, where the indentation of the
/// resulting snippet of the given span.
///
/// # Example
///
/// ```rust,ignore
/// snippet_block(cx, block.span, "..", None)
/// // where, `block` is the block of the if expr
/// if x {
/// y;
/// }
/// // will return the snippet
/// {
/// y;
/// }
/// ```
///
/// ```rust,ignore
/// snippet_block(cx, block.span, "..", Some(if_expr.span))
/// // where, `block` is the block of the if expr
/// if x {
/// y;
/// }
/// // will return the snippet
/// {
/// y;
/// } // aligned with `if`
/// ```
/// Note that the first line of the snippet always has 0 indentation.
pub fn snippet_block<'a, T: LintContext>(
cx: &T,
span: Span,
default: &'a str,
indent_relative_to: Option<Span>,
) -> Cow<'a, str> {
let snip = snippet(cx, span, default);
let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
reindent_multiline(snip, true, indent)
}
/// Same as `snippet_block`, but adapts the applicability level by the rules of
/// `snippet_with_applicability`.
pub fn snippet_block_with_applicability<'a, T: LintContext>(
cx: &T,
span: Span,
default: &'a str,
indent_relative_to: Option<Span>,
applicability: &mut Applicability,
) -> Cow<'a, str> {
let snip = snippet_with_applicability(cx, span, default, applicability);
let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
reindent_multiline(snip, true, indent)
}
/// Same as `snippet_with_applicability`, but first walks the span up to the given context. This
/// will result in the macro call, rather then the expansion, if the span is from a child context.
/// If the span is not from a child context, it will be used directly instead.
///
/// e.g. Given the expression `&vec![]`, getting a snippet from the span for `vec![]` as a HIR node
/// would result in `box []`. If given the context of the address of expression, this function will
/// correctly get a snippet of `vec![]`.
pub fn snippet_with_context(
cx: &LateContext<'_>,
span: Span,
outer: SyntaxContext,
default: &'a str,
applicability: &mut Applicability,
) -> Cow<'a, str> {
let outer_span = hygiene::walk_chain(span, outer);
let span = if outer_span.ctxt() == outer {
outer_span
} else {
// The span is from a macro argument, and the outer context is the macro using the argument
if *applicability != Applicability::Unspecified {
*applicability = Applicability::MaybeIncorrect;
}
// TODO: get the argument span.
span
};
snippet_with_applicability(cx, span, default, applicability)
}
/// Returns a new Span that extends the original Span to the first non-whitespace char of the first
/// line.
///
/// ```rust,ignore
/// let x = ();
/// // ^^
/// // will be converted to
/// let x = ();
/// // ^^^^^^^^^^
/// ```
pub fn first_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
first_char_in_first_line(cx, span).map_or(span, |first_char_pos| span.with_lo(first_char_pos))
}
fn first_char_in_first_line<T: LintContext>(cx: &T, span: Span) -> Option<BytePos> {
let line_span = line_span(cx, span);
snippet_opt(cx, line_span).and_then(|snip| {
snip.find(|c: char| !c.is_whitespace())
.map(|pos| line_span.lo() + BytePos::from_usize(pos))
})
}
/// Returns the indentation of the line of a span
///
/// ```rust,ignore
/// let x = ();
/// // ^^ -- will return 0
/// let x = ();
/// // ^^ -- will return 4
/// ```
pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
}
/// Returns the positon just before rarrow
///
/// ```rust,ignore
/// fn into(self) -> () {}
/// ^
/// // in case of unformatted code
/// fn into2(self)-> () {}
/// ^
/// fn into3(self) -> () {}
/// ^
/// ```
pub fn position_before_rarrow(s: &str) -> Option<usize> {
s.rfind("->").map(|rpos| {
let mut rpos = rpos;
let chars: Vec<char> = s.chars().collect();
while rpos > 1 {
if let Some(c) = chars.get(rpos - 1) {
if c.is_whitespace() {
rpos -= 1;
continue;
}
}
break;
}
rpos
})
}
/// Extends the span to the beginning of the spans line, incl. whitespaces.
///
/// ```rust,ignore
/// let x = ();
/// // ^^
/// // will be converted to
/// let x = ();
/// // ^^^^^^^^^^^^^^
/// ```
fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
let span = original_sp(span, DUMMY_SP);
let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
let line_no = source_map_and_line.line;
let line_start = source_map_and_line.sf.lines[line_no];
Span::new(line_start, span.hi(), span.ctxt())
}
/// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
/// Also takes an `Option<String>` which can be put inside the braces.
pub fn expr_block<'a, T: LintContext>(
cx: &T,
expr: &Expr<'_>,
option: Option<String>,
default: &'a str,
indent_relative_to: Option<Span>,
) -> Cow<'a, str> {
let code = snippet_block(cx, expr.span, default, indent_relative_to);
let string = option.unwrap_or_default();
if expr.span.from_expansion() {
Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
} else if let ExprKind::Block(_, _) = expr.kind {
Cow::Owned(format!("{}{}", code, string))
} else if string.is_empty() {
Cow::Owned(format!("{{ {} }}", code))
} else {
Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
}
}
/// Reindent a multiline string with possibility of ignoring the first line.
#[allow(clippy::needless_pass_by_value)]
pub fn reindent_multiline(s: Cow<'_, str>, ignore_first: bool, indent: Option<usize>) -> Cow<'_, str> {
let s_space = reindent_multiline_inner(&s, ignore_first, indent, ' ');
let s_tab = reindent_multiline_inner(&s_space, ignore_first, indent, '\t');
reindent_multiline_inner(&s_tab, ignore_first, indent, ' ').into()
}
fn reindent_multiline_inner(s: &str, ignore_first: bool, indent: Option<usize>, ch: char) -> String {
let x = s
.lines()
.skip(ignore_first as usize)
.filter_map(|l| {
if l.is_empty() {
None
} else {
// ignore empty lines
Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
}
})
.min()
.unwrap_or(0);
let indent = indent.unwrap_or(0);
s.lines()
.enumerate()
.map(|(i, l)| {
if (ignore_first && i == 0) || l.is_empty() {
l.to_owned()
} else if x > indent {
l.split_at(x - indent).1.to_owned()
} else {
" ".repeat(indent - x) + l
}
})
.collect::<Vec<String>>()
.join("\n")
}
/// Gets the parent expression, if any –- this is useful to constrain a lint.
pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
let map = &cx.tcx.hir();
let hir_id = e.hir_id;
let parent_id = map.get_parent_node(hir_id);
if hir_id == parent_id {
return None;
}
map.find(parent_id).and_then(|node| {
if let Node::Expr(parent) = node {
Some(parent)
} else {
None
}
})
}
pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
let map = &cx.tcx.hir();
let enclosing_node = map
.get_enclosing_scope(hir_id)
.and_then(|enclosing_id| map.find(enclosing_id));
enclosing_node.and_then(|node| match node {
Node::Block(block) => Some(block),
Node::Item(&Item {
kind: ItemKind::Fn(_, _, eid),
..
})
| Node::ImplItem(&ImplItem {
kind: ImplItemKind::Fn(_, eid),
..
}) => match cx.tcx.hir().body(eid).value.kind {
ExprKind::Block(ref block, _) => Some(block),
_ => None,
},
_ => None,
})
}
/// Gets the parent node if it's an impl block.
pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
let map = tcx.hir();
match map.parent_iter(id).next() {
Some((
_,
Node::Item(Item {
kind: ItemKind::Impl(imp),
..
}),
)) => Some(imp),
_ => None,
}
}
/// Returns the base type for HIR references and pointers.
pub fn walk_ptrs_hir_ty<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
match ty.kind {
TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
_ => ty,
}
}
/// Returns the base type for references and raw pointers, and count reference
/// depth.
pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
match ty.kind() {
ty::Ref(_, ty, _) => inner(ty, depth + 1),
_ => (ty, depth),
}
}
inner(ty, 0)
}
/// Checks whether the given expression is a constant integer of the given value.
/// unlike `is_integer_literal`, this version does const folding
pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
if is_integer_literal(e, value) {
return true;
}
let map = cx.tcx.hir();
let parent_item = map.get_parent_item(e.hir_id);
if let Some((Constant::Int(v), _)) = map
.maybe_body_owned_by(parent_item)
.and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
{
value == v
} else {
false
}
}
/// Checks whether the given expression is a constant literal of the given value.
pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
// FIXME: use constant folding
if let ExprKind::Lit(ref spanned) = expr.kind {
if let LitKind::Int(v, _) = spanned.node {
return v == value;
}
}
false
}
/// Returns `true` if the given `Expr` has been coerced before.
///
/// Examples of coercions can be found in the Nomicon at
/// <https://doc.rust-lang.org/nomicon/coercions.html>.
///
/// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
/// information on adjustments and coercions.
pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
cx.typeck_results().adjustments().get(e.hir_id).is_some()
}
/// Returns the pre-expansion span if is this comes from an expansion of the
/// macro `name`.
/// See also `is_direct_expn_of`.
#[must_use]
pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
loop {
if span.from_expansion() {
let data = span.ctxt().outer_expn_data();
let new_span = data.call_site;
if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
if mac_name.as_str() == name {
return Some(new_span);
}
}
span = new_span;
} else {
return None;
}
}
}
/// Returns the pre-expansion span if the span directly comes from an expansion
/// of the macro `name`.
/// The difference with `is_expn_of` is that in
/// ```rust,ignore
/// foo!(bar!(42));
/// ```
/// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
/// `bar!` by
/// `is_direct_expn_of`.
#[must_use]
pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
if span.from_expansion() {
let data = span.ctxt().outer_expn_data();
let new_span = data.call_site;
if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
if mac_name.as_str() == name {
return Some(new_span);
}
}
}
None
}
/// Convenience function to get the return type of a function.
pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
cx.tcx.erase_late_bound_regions(ret_ty)
}
/// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
ty.walk().any(|inner| match inner.unpack() {
GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
})
}
/// Returns `true` if the given type is an `unsafe` function.
pub fn type_is_unsafe_function<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
match ty.kind() {
ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
_ => false,
}
}
pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
}
/// Checks if an expression is constructing a tuple-like enum variant or struct
pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
if let ExprKind::Call(ref fun, _) = expr.kind {
if let ExprKind::Path(ref qp) = fun.kind {
let res = cx.qpath_res(qp, fun.hir_id);
return match res {
def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
_ => false,
};
}
}
false
}
/// Returns `true` if a pattern is refutable.
// TODO: should be implemented using rustc/mir_build/thir machinery
pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
matches!(
cx.qpath_res(qpath, id),
def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
)
}
fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
i.any(|pat| is_refutable(cx, pat))
}
match pat.kind {
PatKind::Wild => false,
PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
PatKind::Lit(..) | PatKind::Range(..) => true,
PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
PatKind::Or(ref pats) => {
// TODO: should be the honest check, that pats is exhaustive set
are_refutable(cx, pats.iter().map(|pat| &**pat))
},
PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
PatKind::Struct(ref qpath, ref fields, _) => {
is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
},
PatKind::TupleStruct(ref qpath, ref pats, _) => {
is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
},
PatKind::Slice(ref head, ref middle, ref tail) => {
match &cx.typeck_results().node_type(pat.hir_id).kind() {
ty::Slice(..) => {
// [..] is the only irrefutable slice pattern.
!head.is_empty() || middle.is_none() || !tail.is_empty()
},
ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat)),
_ => {
// unreachable!()
true
},
}
},
}
}
/// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
/// implementations have.
pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
attrs.iter().any(|attr| attr.has_name(sym::automatically_derived))
}
/// Remove blocks around an expression.
///
/// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
/// themselves.
pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
while let ExprKind::Block(ref block, ..) = expr.kind {
match (block.stmts.is_empty(), block.expr.as_ref()) {
(true, Some(e)) => expr = e,
_ => break,
}
}
expr
}
pub fn is_self(slf: &Param<'_>) -> bool {
if let PatKind::Binding(.., name, _) = slf.pat.kind {
name.name == kw::SelfLower
} else {
false
}
}
pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
if_chain! {
if let TyKind::Path(QPath::Resolved(None, ref path)) = slf.kind;
if let Res::SelfTy(..) = path.res;
then {
return true
}
}
false
}
pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
(0..decl.inputs.len()).map(move |i| &body.params[i])
}
/// Checks if a given expression is a match expression expanded from the `?`
/// operator or the `try` macro.
pub fn is_try<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
fn is_ok(arm: &Arm<'_>) -> bool {
if_chain! {
if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
if match_qpath(path, &paths::RESULT_OK[1..]);
if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
if path_to_local_id(arm.body, hir_id);
then {
return true;
}
}
false
}
fn is_err(arm: &Arm<'_>) -> bool {
if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
match_qpath(path, &paths::RESULT_ERR[1..])
} else {
false
}
}
if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
// desugared from a `?` operator
if let MatchSource::TryDesugar = *source {
return Some(expr);
}
if_chain! {
if arms.len() == 2;
if arms[0].guard.is_none();
if arms[1].guard.is_none();
if (is_ok(&arms[0]) && is_err(&arms[1])) ||
(is_ok(&arms[1]) && is_err(&arms[0]));
then {
return Some(expr);
}
}
}
None
}
/// Returns `true` if the lint is allowed in the current context
///
/// Useful for skipping long running code when it's unnecessary
pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
}
pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
while let PatKind::Ref(subpat, _) = pat.kind {
pat = subpat;
}
pat
}
pub fn int_bits(tcx: TyCtxt<'_>, ity: ty::IntTy) -> u64 {
Integer::from_int_ty(&tcx, ity).size().bits()
}
#[allow(clippy::cast_possible_wrap)]
/// Turn a constant int byte representation into an i128
pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ty::IntTy) -> i128 {
let amt = 128 - int_bits(tcx, ity);
((u as i128) << amt) >> amt
}
#[allow(clippy::cast_sign_loss)]
/// clip unused bytes
pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ty::IntTy) -> u128 {
let amt = 128 - int_bits(tcx, ity);
((u as u128) << amt) >> amt
}
/// clip unused bytes
pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ty::UintTy) -> u128 {
let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
let amt = 128 - bits;
(u << amt) >> amt
}
/// Removes block comments from the given `Vec` of lines.
///
/// # Examples
///
/// ```rust,ignore
/// without_block_comments(vec!["/*", "foo", "*/"]);
/// // => vec![]
///
/// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
/// // => vec!["bar"]
/// ```
pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
let mut without = vec![];
let mut nest_level = 0;
for line in lines {
if line.contains("/*") {
nest_level += 1;
continue;
} else if line.contains("*/") {
nest_level -= 1;
continue;
}
if nest_level == 0 {
without.push(line);
}
}
without
}
pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
let map = &tcx.hir();
let mut prev_enclosing_node = None;
let mut enclosing_node = node;
while Some(enclosing_node) != prev_enclosing_node {
if is_automatically_derived(map.attrs(enclosing_node)) {
return true;
}
prev_enclosing_node = Some(enclosing_node);
enclosing_node = map.get_parent_item(enclosing_node);
}
false
}
/// Returns true if ty has `iter` or `iter_mut` methods
pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<Symbol> {
// FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
// exists and has the desired signature. Unfortunately FnCtxt is not exported
// so we can't use its `lookup_method` method.
let into_iter_collections: &[Symbol] = &[
sym::vec_type,
sym::option_type,
sym::result_type,
sym::BTreeMap,
sym::BTreeSet,
sym::vecdeque_type,
sym::LinkedList,
sym::BinaryHeap,
sym::hashset_type,
sym::hashmap_type,
sym::PathBuf,
sym::Path,
sym::Receiver,
];
let ty_to_check = match probably_ref_ty.kind() {
ty::Ref(_, ty_to_check, _) => ty_to_check,
_ => probably_ref_ty,
};
let def_id = match ty_to_check.kind() {
ty::Array(..) => return Some(sym::array),
ty::Slice(..) => return Some(sym::slice),
ty::Adt(adt, _) => adt.did,
_ => return None,
};
for &name in into_iter_collections {
if cx.tcx.is_diagnostic_item(name, def_id) {
return Some(cx.tcx.item_name(def_id));
}
}
None
}
/// Matches a function call with the given path and returns the arguments.
///
/// Usage:
///
/// ```rust,ignore
/// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
/// ```
pub fn match_function_call<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
path: &[&str],
) -> Option<&'tcx [Expr<'tcx>]> {
if_chain! {
if let ExprKind::Call(ref fun, ref args) = expr.kind;
if let ExprKind::Path(ref qpath) = fun.kind;
if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
if match_def_path(cx, fun_def_id, path);
then {
return Some(&args)
}
};
None
}
// FIXME: Per https://doc.rust-lang.org/nightly/nightly-rustc/rustc_trait_selection/infer/at/struct.At.html#method.normalize
// this function can be removed once the `normalizie` method does not panic when normalization does
// not succeed
/// Checks if `Ty` is normalizable. This function is useful
/// to avoid crashes on `layout_of`.
pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
is_normalizable_helper(cx, param_env, ty, &mut HashMap::new())
}
fn is_normalizable_helper<'tcx>(
cx: &LateContext<'tcx>,
param_env: ty::ParamEnv<'tcx>,
ty: Ty<'tcx>,
cache: &mut HashMap<Ty<'tcx>, bool>,
) -> bool {
if let Some(&cached_result) = cache.get(ty) {
return cached_result;
}
// prevent recursive loops, false-negative is better than endless loop leading to stack overflow
cache.insert(ty, false);
let result = cx.tcx.infer_ctxt().enter(|infcx| {
let cause = rustc_middle::traits::ObligationCause::dummy();
if infcx.at(&cause, param_env).normalize(ty).is_ok() {
match ty.kind() {
ty::Adt(def, substs) => def.variants.iter().all(|variant| {
variant
.fields
.iter()
.all(|field| is_normalizable_helper(cx, param_env, field.ty(cx.tcx, substs), cache))
}),
_ => ty.walk().all(|generic_arg| match generic_arg.unpack() {
GenericArgKind::Type(inner_ty) if inner_ty != ty => {
is_normalizable_helper(cx, param_env, inner_ty, cache)
},
_ => true, // if inner_ty == ty, we've already checked it
}),
}
} else {
false
}
});
cache.insert(ty, result);
result
}
pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
// We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
// accepts only that. We should probably move to Symbols in Clippy as well.
let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
cx.match_def_path(did, &syms)
}
pub fn match_panic_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx [Expr<'tcx>]> {
match_function_call(cx, expr, &paths::BEGIN_PANIC)
.or_else(|| match_function_call(cx, expr, &paths::BEGIN_PANIC_FMT))
.or_else(|| match_function_call(cx, expr, &paths::PANIC_ANY))
.or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC))
.or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_FMT))
.or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_STR))
}
pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
match_def_path(cx, did, &paths::BEGIN_PANIC)
|| match_def_path(cx, did, &paths::BEGIN_PANIC_FMT)
|| match_def_path(cx, did, &paths::PANIC_ANY)
|| match_def_path(cx, did, &paths::PANICKING_PANIC)
|| match_def_path(cx, did, &paths::PANICKING_PANIC_FMT)
|| match_def_path(cx, did, &paths::PANICKING_PANIC_STR)
}
/// Returns the list of condition expressions and the list of blocks in a
/// sequence of `if/else`.
/// E.g., this returns `([a, b], [c, d, e])` for the expression
/// `if a { c } else if b { d } else { e }`.
pub fn if_sequence<'tcx>(
mut expr: &'tcx Expr<'tcx>,
) -> (SmallVec<[&'tcx Expr<'tcx>; 1]>, SmallVec<[&'tcx Block<'tcx>; 1]>) {
let mut conds = SmallVec::new();
let mut blocks: SmallVec<[&Block<'_>; 1]> = SmallVec::new();
while let ExprKind::If(ref cond, ref then_expr, ref else_expr) = expr.kind {
conds.push(&**cond);
if let ExprKind::Block(ref block, _) = then_expr.kind {
blocks.push(block);
} else {
panic!("ExprKind::If node is not an ExprKind::Block");
}
if let Some(ref else_expr) = *else_expr {
expr = else_expr;
} else {
break;
}
}
// final `else {..}`
if !blocks.is_empty() {
if let ExprKind::Block(ref block, _) = expr.kind {
blocks.push(&**block);
}
}
(conds, blocks)
}
pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
let map = cx.tcx.hir();
let parent_id = map.get_parent_node(expr.hir_id);
let parent_node = map.get(parent_id);
matches!(
parent_node,
Node::Expr(Expr {
kind: ExprKind::If(_, _, _),
..
})
)
}
// Finds the attribute with the given name, if any
pub fn attr_by_name<'a>(attrs: &'a [Attribute], name: &'_ str) -> Option<&'a Attribute> {
attrs
.iter()
.find(|attr| attr.ident().map_or(false, |ident| ident.as_str() == name))
}
// Finds the `#[must_use]` attribute, if any
pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
attr_by_name(attrs, "must_use")
}
// Returns whether the type has #[must_use] attribute
pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
match ty.kind() {
ty::Adt(ref adt, _) => must_use_attr(&cx.tcx.get_attrs(adt.did)).is_some(),
ty::Foreign(ref did) => must_use_attr(&cx.tcx.get_attrs(*did)).is_some(),
ty::Slice(ref ty)
| ty::Array(ref ty, _)
| ty::RawPtr(ty::TypeAndMut { ref ty, .. })
| ty::Ref(_, ref ty, _) => {
// for the Array case we don't need to care for the len == 0 case
// because we don't want to lint functions returning empty arrays
is_must_use_ty(cx, *ty)
},
ty::Tuple(ref substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
ty::Opaque(ref def_id, _) => {
for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
if let ty::PredicateKind::Trait(trait_predicate, _) = predicate.kind().skip_binder() {
if must_use_attr(&cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
return true;
}
}
}
false
},
ty::Dynamic(binder, _) => {
for predicate in binder.iter() {
if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
if must_use_attr(&cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
return true;
}
}
}
false
},
_ => false,
}
}
// check if expr is calling method or function with #[must_use] attribute
pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
let did = match expr.kind {
ExprKind::Call(ref path, _) => if_chain! {
if let ExprKind::Path(ref qpath) = path.kind;
if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
then {
Some(did)
} else {
None
}
},
ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
_ => None,
};
did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
}
pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
attr.path == sym::no_std
} else {
false
}
})
}
/// Check if parent of a hir node is a trait implementation block.
/// For example, `f` in
/// ```rust,ignore
/// impl Trait for S {
/// fn f() {}
/// }
/// ```
pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
} else {
false
}
}
/// Check if it's even possible to satisfy the `where` clause for the item.
///
/// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
///
/// ```ignore
/// fn foo() where i32: Iterator {
/// for _ in 2i32 {}
/// }
/// ```
pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
use rustc_trait_selection::traits;
let predicates = cx
.tcx
.predicates_of(did)
.predicates
.iter()
.filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
traits::impossible_predicates(
cx.tcx,
traits::elaborate_predicates(cx.tcx, predicates)
.map(|o| o.predicate)
.collect::<Vec<_>>(),
)
}
/// Returns the `DefId` of the callee if the given expression is a function or method call.
pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
match &expr.kind {
ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
ExprKind::Call(
Expr {
kind: ExprKind::Path(qpath),
hir_id: path_hir_id,
..
},
..,
) => cx.typeck_results().qpath_res(qpath, *path_hir_id).opt_def_id(),
_ => None,
}
}
pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
lints.iter().any(|lint| {
matches!(
cx.tcx.lint_level_at_node(lint, id),
(Level::Forbid | Level::Deny | Level::Warn, _)
)
})
}
/// Returns true iff the given type is a primitive (a bool or char, any integer or floating-point
/// number type, a str, or an array, slice, or tuple of those types).
pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
match ty.kind() {
ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str => true,
ty::Ref(_, inner, _) if *inner.kind() == ty::Str => true,
ty::Array(inner_type, _) | ty::Slice(inner_type) => is_recursively_primitive_type(inner_type),
ty::Tuple(inner_types) => inner_types.types().all(is_recursively_primitive_type),
_ => false,
}
}
/// Returns Option<String> where String is a textual representation of the type encapsulated in the
/// slice iff the given expression is a slice of primitives (as defined in the
/// `is_recursively_primitive_type` function) and None otherwise.
pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
let expr_kind = expr_type.kind();
let is_primitive = match expr_kind {
ty::Slice(element_type) => is_recursively_primitive_type(element_type),
ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &ty::Slice(_)) => {
if let ty::Slice(element_type) = inner_ty.kind() {
is_recursively_primitive_type(element_type)
} else {
unreachable!()
}
},
_ => false,
};
if is_primitive {
// if we have wrappers like Array, Slice or Tuple, print these
// and get the type enclosed in the slice ref
match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
ty::Slice(..) => return Some("slice".into()),
ty::Array(..) => return Some("array".into()),
ty::Tuple(..) => return Some("tuple".into()),
_ => {
// is_recursively_primitive_type() should have taken care
// of the rest and we can rely on the type that is found
let refs_peeled = expr_type.peel_refs();
return Some(refs_peeled.walk().last().unwrap().to_string());
},
}
}
None
}
/// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
/// `hash` must be comformed with `eq`
pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
where
Hash: Fn(&T) -> u64,
Eq: Fn(&T, &T) -> bool,
{
if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
return vec![(&exprs[0], &exprs[1])];
}
let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
let mut map: FxHashMap<_, Vec<&_>> =
FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
for expr in exprs {
match map.entry(hash(expr)) {
Entry::Occupied(mut o) => {
for o in o.get() {
if eq(o, expr) {
match_expr_list.push((o, expr));
}
}
o.get_mut().push(expr);
},
Entry::Vacant(v) => {
v.insert(vec![expr]);
},
}
}
match_expr_list
}
/// Peels off all references on the pattern. Returns the underlying pattern and the number of
/// references removed.
pub fn peel_hir_pat_refs(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
fn peel(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
if let PatKind::Ref(pat, _) = pat.kind {
peel(pat, count + 1)
} else {
(pat, count)
}
}
peel(pat, 0)
}
/// Peels off up to the given number of references on the expression. Returns the underlying
/// expression and the number of references removed.
pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
fn f(expr: &'a Expr<'a>, count: usize, target: usize) -> (&'a Expr<'a>, usize) {
match expr.kind {
ExprKind::AddrOf(_, _, expr) if count != target => f(expr, count + 1, target),
_ => (expr, count),
}
}
f(expr, 0, count)
}
/// Peels off all references on the expression. Returns the underlying expression and the number of
/// references removed.
pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
fn f(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
match expr.kind {
ExprKind::AddrOf(BorrowKind::Ref, _, expr) => f(expr, count + 1),
_ => (expr, count),
}
}
f(expr, 0)
}
/// Peels off all references on the type. Returns the underlying type and the number of references
/// removed.
pub fn peel_mid_ty_refs(ty: Ty<'_>) -> (Ty<'_>, usize) {
fn peel(ty: Ty<'_>, count: usize) -> (Ty<'_>, usize) {
if let ty::Ref(_, ty, _) = ty.kind() {
peel(ty, count + 1)
} else {
(ty, count)
}
}
peel(ty, 0)
}
/// Peels off all references on the type.Returns the underlying type, the number of references
/// removed, and whether the pointer is ultimately mutable or not.
pub fn peel_mid_ty_refs_is_mutable(ty: Ty<'_>) -> (Ty<'_>, usize, Mutability) {
fn f(ty: Ty<'_>, count: usize, mutability: Mutability) -> (Ty<'_>, usize, Mutability) {
match ty.kind() {
ty::Ref(_, ty, Mutability::Mut) => f(ty, count + 1, mutability),
ty::Ref(_, ty, Mutability::Not) => f(ty, count + 1, Mutability::Not),
_ => (ty, count, mutability),
}
}
f(ty, 0, Mutability::Mut)
}
#[macro_export]
macro_rules! unwrap_cargo_metadata {
($cx: ident, $lint: ident, $deps: expr) => {{
let mut command = cargo_metadata::MetadataCommand::new();
if !$deps {
command.no_deps();
}
match command.exec() {
Ok(metadata) => metadata,
Err(err) => {
span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
return;
},
}
}};
}
pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
if_chain! {
if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
if let Res::Def(_, def_id) = path.res;
then {
cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr)
} else {
false
}
}
}
/// Check if the resolution of a given path is an `Ok` variant of `Result`.
pub fn is_ok_ctor(cx: &LateContext<'_>, res: Res) -> bool {
if let Some(ok_id) = cx.tcx.lang_items().result_ok_variant() {
if let Res::Def(DefKind::Ctor(CtorOf::Variant, CtorKind::Fn), id) = res {
if let Some(variant_id) = cx.tcx.parent(id) {
return variant_id == ok_id;
}
}
}
false
}
/// Check if the resolution of a given path is a `Some` variant of `Option`.
pub fn is_some_ctor(cx: &LateContext<'_>, res: Res) -> bool {
if let Some(some_id) = cx.tcx.lang_items().option_some_variant() {
if let Res::Def(DefKind::Ctor(CtorOf::Variant, CtorKind::Fn), id) = res {
if let Some(variant_id) = cx.tcx.parent(id) {
return variant_id == some_id;
}
}
}
false
}
#[cfg(test)]
mod test {
use super::{reindent_multiline, without_block_comments};
#[test]
fn test_reindent_multiline_single_line() {
assert_eq!("", reindent_multiline("".into(), false, None));
assert_eq!("...", reindent_multiline("...".into(), false, None));
assert_eq!("...", reindent_multiline(" ...".into(), false, None));
assert_eq!("...", reindent_multiline("\t...".into(), false, None));
assert_eq!("...", reindent_multiline("\t\t...".into(), false, None));
}
#[test]
#[rustfmt::skip]
fn test_reindent_multiline_block() {
assert_eq!("\
if x {
y
} else {
z
}", reindent_multiline(" if x {
y
} else {
z
}".into(), false, None));
assert_eq!("\
if x {
\ty
} else {
\tz
}", reindent_multiline(" if x {
\ty
} else {
\tz
}".into(), false, None));
}
#[test]
#[rustfmt::skip]
fn test_reindent_multiline_empty_line() {
assert_eq!("\
if x {
y
} else {
z
}", reindent_multiline(" if x {
y
} else {
z
}".into(), false, None));
}
#[test]
#[rustfmt::skip]
fn test_reindent_multiline_lines_deeper() {
assert_eq!("\
if x {
y
} else {
z
}", reindent_multiline("\
if x {
y
} else {
z
}".into(), true, Some(8)));
}
#[test]
fn test_without_block_comments_lines_without_block_comments() {
let result = without_block_comments(vec!["/*", "", "*/"]);
println!("result: {:?}", result);
assert!(result.is_empty());
let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
let result = without_block_comments(vec!["/* rust", "", "*/"]);
assert!(result.is_empty());
let result = without_block_comments(vec!["/* one-line comment */"]);
assert!(result.is_empty());
let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
assert!(result.is_empty());
let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
assert!(result.is_empty());
let result = without_block_comments(vec!["foo", "bar", "baz"]);
assert_eq!(result, vec!["foo", "bar", "baz"]);
}
}
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