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Auto merge of #15179 - ponyii:fix/default-values-of-const-params-are-ignored, r=HKalbasi

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the "add missing members" assists: implemented substitution of default values of const params

To achieve this, I've made `hir::ConstParamData` store the default values
This commit is contained in:
bors 2023-08-15 10:17:43 +00:00
commit b771de3fdc
18 changed files with 266 additions and 104 deletions
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8
crates/hir-def/src/generics.rs
View file

@ -25,7 +25,7 @@ use crate::{
lower::LowerCtx,
nameres::{DefMap, MacroSubNs},
src::{HasChildSource, HasSource},
type_ref::{LifetimeRef, TypeBound, TypeRef},
type_ref::{ConstRef, LifetimeRef, TypeBound, TypeRef},
AdtId, ConstParamId, GenericDefId, HasModule, LifetimeParamId, LocalLifetimeParamId,
LocalTypeOrConstParamId, Lookup, TypeOrConstParamId, TypeParamId,
};
@ -49,7 +49,7 @@ pub struct LifetimeParamData {
pub struct ConstParamData {
pub name: Name,
pub ty: Interned<TypeRef>,
pub has_default: bool,
pub default: Option<ConstRef>,
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
@ -76,7 +76,7 @@ impl TypeOrConstParamData {
pub fn has_default(&self) -> bool {
match self {
TypeOrConstParamData::TypeParamData(it) => it.default.is_some(),
TypeOrConstParamData::ConstParamData(it) => it.has_default,
TypeOrConstParamData::ConstParamData(it) => it.default.is_some(),
}
}
@ -307,7 +307,7 @@ impl GenericParams {
let param = ConstParamData {
name,
ty: Interned::new(ty),
has_default: const_param.default_val().is_some(),
default: ConstRef::from_const_param(lower_ctx, &const_param),
};
let idx = self.type_or_consts.alloc(param.into());
add_param_attrs(idx.into(), ast::GenericParam::ConstParam(const_param));

11
crates/hir-def/src/hir/type_ref.rs
View file

@ -393,6 +393,17 @@ impl ConstRef {
Self::Scalar(LiteralConstRef::Unknown)
}
pub(crate) fn from_const_param(
lower_ctx: &LowerCtx<'_>,
param: &ast::ConstParam,
) -> Option<Self> {
let default = param.default_val();
match default {
Some(_) => Some(Self::from_const_arg(lower_ctx, default)),
None => None,
}
}
pub fn display<'a>(&'a self, db: &'a dyn ExpandDatabase) -> impl fmt::Display + 'a {
struct Display<'a>(&'a dyn ExpandDatabase, &'a ConstRef);
impl fmt::Display for Display<'_> {

17
crates/hir-ty/src/lib.rs
View file

@ -52,12 +52,14 @@ use hir_expand::name;
use la_arena::{Arena, Idx};
use mir::{MirEvalError, VTableMap};
use rustc_hash::FxHashSet;
use syntax::ast::{make, ConstArg};
use traits::FnTrait;
use triomphe::Arc;
use utils::Generics;
use crate::{
consteval::unknown_const, db::HirDatabase, infer::unify::InferenceTable, utils::generics,
consteval::unknown_const, db::HirDatabase, display::HirDisplay, infer::unify::InferenceTable,
utils::generics,
};
pub use autoderef::autoderef;
@ -719,3 +721,16 @@ where
value.visit_with(&mut collector, DebruijnIndex::INNERMOST);
collector.placeholders.into_iter().collect()
}
pub fn known_const_to_ast(konst: &Const, db: &dyn HirDatabase) -> Option<ConstArg> {
if let ConstValue::Concrete(c) = &konst.interned().value {
match c.interned {
ConstScalar::UnevaluatedConst(GeneralConstId::InTypeConstId(cid), _) => {
return Some(cid.source(db.upcast()));
}
ConstScalar::Unknown => return None,
_ => (),
}
}
Some(make::expr_const_value(konst.display(db).to_string().as_str()))
}

83
crates/hir-ty/src/lower.rs
View file

@ -212,6 +212,19 @@ impl<'a> TyLoweringContext<'a> {
self.lower_ty_ext(type_ref).0
}
pub fn lower_const(&self, const_ref: &ConstRef, const_type: Ty) -> Const {
const_or_path_to_chalk(
self.db,
self.resolver,
self.owner,
const_type,
const_ref,
self.type_param_mode,
|| self.generics(),
self.in_binders,
)
}
fn generics(&self) -> Generics {
generics(
self.db.upcast(),
@ -241,17 +254,7 @@ impl<'a> TyLoweringContext<'a> {
}
TypeRef::Array(inner, len) => {
let inner_ty = self.lower_ty(inner);
let const_len = const_or_path_to_chalk(
self.db,
self.resolver,
self.owner,
TyBuilder::usize(),
len,
self.type_param_mode,
|| self.generics(),
self.in_binders,
);
let const_len = self.lower_const(len, TyBuilder::usize());
TyKind::Array(inner_ty, const_len).intern(Interner)
}
TypeRef::Slice(inner) => {
@ -846,18 +849,7 @@ impl<'a> TyLoweringContext<'a> {
arg,
&mut (),
|_, type_ref| self.lower_ty(type_ref),
|_, c, ty| {
const_or_path_to_chalk(
self.db,
self.resolver,
self.owner,
ty,
c,
self.type_param_mode,
|| self.generics(),
self.in_binders,
)
},
|_, const_ref, ty| self.lower_const(const_ref, ty),
) {
had_explicit_args = true;
substs.push(x);
@ -1603,24 +1595,35 @@ pub(crate) fn generic_defaults_query(
.iter()
.enumerate()
.map(|(idx, (id, p))| {
let p = match p {
TypeOrConstParamData::TypeParamData(p) => p,
TypeOrConstParamData::ConstParamData(_) => {
// FIXME: implement const generic defaults
let val = unknown_const_as_generic(
db.const_param_ty(ConstParamId::from_unchecked(id)),
);
return make_binders(db, &generic_params, val);
match p {
TypeOrConstParamData::TypeParamData(p) => {
let mut ty = p
.default
.as_ref()
.map_or(TyKind::Error.intern(Interner), |t| ctx.lower_ty(t));
// Each default can only refer to previous parameters.
// Type variable default referring to parameter coming
// after it is forbidden (FIXME: report diagnostic)
ty = fallback_bound_vars(ty, idx, parent_start_idx);
crate::make_binders(db, &generic_params, ty.cast(Interner))
}
};
let mut ty =
p.default.as_ref().map_or(TyKind::Error.intern(Interner), |t| ctx.lower_ty(t));
// Each default can only refer to previous parameters.
// Type variable default referring to parameter coming
// after it is forbidden (FIXME: report diagnostic)
ty = fallback_bound_vars(ty, idx, parent_start_idx);
crate::make_binders(db, &generic_params, ty.cast(Interner))
TypeOrConstParamData::ConstParamData(p) => {
let mut val = p.default.as_ref().map_or_else(
|| {
unknown_const_as_generic(
db.const_param_ty(ConstParamId::from_unchecked(id)),
)
},
|c| {
let c = ctx.lower_const(c, ctx.lower_ty(&p.ty));
c.cast(Interner)
},
);
// Each default can only refer to previous parameters, see above.
val = fallback_bound_vars(val, idx, parent_start_idx);
make_binders(db, &generic_params, val)
}
}
})
// FIXME: use `Arc::from_iter` when it becomes available
.collect::<Vec<_>>(),

22
crates/hir/src/lib.rs
View file

@ -63,12 +63,13 @@ use hir_ty::{
all_super_traits, autoderef,
consteval::{try_const_usize, unknown_const_as_generic, ConstEvalError, ConstExt},
diagnostics::BodyValidationDiagnostic,
known_const_to_ast,
layout::{Layout as TyLayout, RustcEnumVariantIdx, TagEncoding},
method_resolution::{self, TyFingerprint},
mir::{self, interpret_mir},
primitive::UintTy,
traits::FnTrait,
AliasTy, CallableDefId, CallableSig, Canonical, CanonicalVarKinds, Cast, ClosureId,
AliasTy, CallableDefId, CallableSig, Canonical, CanonicalVarKinds, Cast, ClosureId, GenericArg,
GenericArgData, Interner, ParamKind, QuantifiedWhereClause, Scalar, Substitution,
TraitEnvironment, TraitRefExt, Ty, TyBuilder, TyDefId, TyExt, TyKind, ValueTyDefId,
WhereClause,
@ -3128,12 +3129,8 @@ impl TypeParam {
}
pub fn default(self, db: &dyn HirDatabase) -> Option<Type> {
let params = db.generic_defaults(self.id.parent());
let local_idx = hir_ty::param_idx(db, self.id.into())?;
let ty = generic_arg_from_param(db, self.id.into())?;
let resolver = self.id.parent().resolver(db.upcast());
let ty = params.get(local_idx)?.clone();
let subst = TyBuilder::placeholder_subst(db, self.id.parent());
let ty = ty.substitute(Interner, &subst);
match ty.data(Interner) {
GenericArgData::Ty(it) => {
Some(Type::new_with_resolver_inner(db, &resolver, it.clone()))
@ -3195,6 +3192,19 @@ impl ConstParam {
pub fn ty(self, db: &dyn HirDatabase) -> Type {
Type::new(db, self.id.parent(), db.const_param_ty(self.id))
}
pub fn default(self, db: &dyn HirDatabase) -> Option<ast::ConstArg> {
let arg = generic_arg_from_param(db, self.id.into())?;
known_const_to_ast(arg.constant(Interner)?, db)
}
}
fn generic_arg_from_param(db: &dyn HirDatabase, id: TypeOrConstParamId) -> Option<GenericArg> {
let params = db.generic_defaults(id.parent);
let local_idx = hir_ty::param_idx(db, id)?;
let ty = params.get(local_idx)?.clone();
let subst = TyBuilder::placeholder_subst(db, id.parent);
Some(ty.substitute(Interner, &subst))
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]

105
crates/ide-assists/src/handlers/add_missing_impl_members.rs
View file

@ -422,7 +422,7 @@ impl<'x, 'y, T, V, U: Default> Trait<'x, 'y, T, V, U> for () {
check_assist(
add_missing_default_members,
r#"
struct Bar<const: N: bool> {
struct Bar<const N: usize> {
bar: [i32, N]
}
@ -439,7 +439,7 @@ impl<const X: usize, Y, Z> Foo<X, Z> for S<Y> {
$0
}"#,
r#"
struct Bar<const: N: bool> {
struct Bar<const N: usize> {
bar: [i32, N]
}
@ -483,6 +483,107 @@ impl<X> Foo<42, {20 + 22}, X> for () {
)
}
#[test]
fn test_const_substitution_with_defaults() {
check_assist(
add_missing_default_members,
r#"
trait Foo<T, const N: usize = 42, const M: bool = false, const P: char = 'a'> {
fn get_n(&self) -> usize { N }
fn get_m(&self) -> bool { M }
fn get_p(&self) -> char { P }
fn get_array(&self, arg: &T) -> [bool; N] { [M; N] }
}
impl<X> Foo<X> for () {
$0
}"#,
r#"
trait Foo<T, const N: usize = 42, const M: bool = false, const P: char = 'a'> {
fn get_n(&self) -> usize { N }
fn get_m(&self) -> bool { M }
fn get_p(&self) -> char { P }
fn get_array(&self, arg: &T) -> [bool; N] { [M; N] }
}
impl<X> Foo<X> for () {
$0fn get_n(&self) -> usize { 42 }
fn get_m(&self) -> bool { false }
fn get_p(&self) -> char { 'a' }
fn get_array(&self, arg: &X) -> [bool; 42] { [false; 42] }
}"#,
);
}
#[test]
fn test_const_substitution_with_defaults_2() {
check_assist(
add_missing_impl_members,
r#"
mod m {
pub const LEN: usize = 42;
pub trait Foo<const M: usize = LEN, const N: usize = M, T = [bool; N]> {
fn get_t(&self) -> T;
}
}
impl m::Foo for () {
$0
}"#,
r#"
mod m {
pub const LEN: usize = 42;
pub trait Foo<const M: usize = LEN, const N: usize = M, T = [bool; N]> {
fn get_t(&self) -> T;
}
}
impl m::Foo for () {
fn get_t(&self) -> [bool; m::LEN] {
${0:todo!()}
}
}"#,
)
}
#[test]
fn test_const_substitution_with_defaults_3() {
check_assist(
add_missing_default_members,
r#"
mod m {
pub const VAL: usize = 0;
pub trait Foo<const N: usize = {40 + 2}, const M: usize = {VAL + 1}> {
fn get_n(&self) -> usize { N }
fn get_m(&self) -> usize { M }
}
}
impl m::Foo for () {
$0
}"#,
r#"
mod m {
pub const VAL: usize = 0;
pub trait Foo<const N: usize = {40 + 2}, const M: usize = {VAL + 1}> {
fn get_n(&self) -> usize { N }
fn get_m(&self) -> usize { M }
}
}
impl m::Foo for () {
$0fn get_n(&self) -> usize { {40 + 2} }
fn get_m(&self) -> usize { {m::VAL + 1} }
}"#,
)
}
#[test]
fn test_cursor_after_empty_impl_def() {
check_assist(

2
crates/ide-assists/src/handlers/extract_function.rs
View file

@ -810,7 +810,7 @@ impl FunctionBody {
(true, konst.body(), Some(sema.to_def(&konst)?.ty(sema.db)))
},
ast::ConstParam(cp) => {
(true, cp.default_val(), Some(sema.to_def(&cp)?.ty(sema.db)))
(true, cp.default_val()?.expr(), Some(sema.to_def(&cp)?.ty(sema.db)))
},
ast::ConstBlockPat(cbp) => {
let expr = cbp.block_expr().map(ast::Expr::BlockExpr);

4
crates/ide-db/src/imports/import_assets.rs
View file

@ -6,7 +6,7 @@ use hir::{
use itertools::Itertools;
use rustc_hash::FxHashSet;
use syntax::{
ast::{self, HasName},
ast::{self, make, HasName},
utils::path_to_string_stripping_turbo_fish,
AstNode, SyntaxNode,
};
@ -607,7 +607,7 @@ impl ImportCandidate {
fn for_name(sema: &Semantics<'_, RootDatabase>, name: &ast::Name) -> Option<Self> {
if sema
.scope(name.syntax())?
.speculative_resolve(&ast::make::ext::ident_path(&name.text()))
.speculative_resolve(&make::ext::ident_path(&name.text()))
.is_some()
{
return None;

44
crates/ide-db/src/path_transform.rs
View file

@ -5,7 +5,7 @@ use either::Either;
use hir::{AsAssocItem, HirDisplay, SemanticsScope};
use rustc_hash::FxHashMap;
use syntax::{
ast::{self, AstNode},
ast::{self, make, AstNode},
ted, SyntaxNode,
};
@ -21,6 +21,7 @@ enum TypeOrConst {
}
type LifetimeName = String;
type DefaultedParam = Either<hir::TypeParam, hir::ConstParam>;
/// `PathTransform` substitutes path in SyntaxNodes in bulk.
///
@ -115,7 +116,7 @@ impl<'a> PathTransform<'a> {
};
let mut type_substs: FxHashMap<hir::TypeParam, ast::Type> = Default::default();
let mut const_substs: FxHashMap<hir::ConstParam, SyntaxNode> = Default::default();
let mut default_types: Vec<hir::TypeParam> = Default::default();
let mut defaulted_params: Vec<DefaultedParam> = Default::default();
self.generic_def
.into_iter()
.flat_map(|it| it.type_params(db))
@ -138,8 +139,8 @@ impl<'a> PathTransform<'a> {
if let Some(default) =
&default.display_source_code(db, source_module.into(), false).ok()
{
type_substs.insert(k, ast::make::ty(default).clone_for_update());
default_types.push(k);
type_substs.insert(k, make::ty(default).clone_for_update());
defaulted_params.push(Either::Left(k));
}
}
}
@ -155,11 +156,19 @@ impl<'a> PathTransform<'a> {
// is a standalone statement or a part of another expresson)
// and sometimes require slight modifications; see
// https://doc.rust-lang.org/reference/statements.html#expression-statements
// (default values in curly brackets can cause the same problem)
const_substs.insert(k, expr.syntax().clone());
}
}
(Either::Left(_), None) => (), // FIXME: get default const value
_ => (), // ignore mismatching params
(Either::Left(k), None) => {
if let Some(default) = k.default(db) {
if let Some(default) = default.expr() {
const_substs.insert(k, default.syntax().clone_for_update());
defaulted_params.push(Either::Right(k));
}
}
}
_ => (), // ignore mismatching params
});
let lifetime_substs: FxHashMap<_, _> = self
.generic_def
@ -175,7 +184,7 @@ impl<'a> PathTransform<'a> {
target_module,
source_scope: self.source_scope,
};
ctx.transform_default_type_substs(default_types);
ctx.transform_default_values(defaulted_params);
ctx
}
}
@ -212,13 +221,19 @@ impl Ctx<'_> {
});
}
fn transform_default_type_substs(&self, default_types: Vec<hir::TypeParam>) {
for k in default_types {
let v = self.type_substs.get(&k).unwrap();
fn transform_default_values(&self, defaulted_params: Vec<DefaultedParam>) {
// By now the default values are simply copied from where they are declared
// and should be transformed. As any value is allowed to refer to previous
// generic (both type and const) parameters, they should be all iterated left-to-right.
for param in defaulted_params {
let value = match param {
Either::Left(k) => self.type_substs.get(&k).unwrap().syntax(),
Either::Right(k) => self.const_substs.get(&k).unwrap(),
};
// `transform_path` may update a node's parent and that would break the
// tree traversal. Thus all paths in the tree are collected into a vec
// so that such operation is safe.
let paths = postorder(&v.syntax()).filter_map(ast::Path::cast).collect::<Vec<_>>();
let paths = postorder(value).filter_map(ast::Path::cast).collect::<Vec<_>>();
for path in paths {
self.transform_path(path);
}
@ -263,15 +278,14 @@ impl Ctx<'_> {
hir::ModuleDef::Trait(trait_ref),
false,
)?;
match ast::make::ty_path(mod_path_to_ast(&found_path)) {
match make::ty_path(mod_path_to_ast(&found_path)) {
ast::Type::PathType(path_ty) => Some(path_ty),
_ => None,
}
});
let segment = ast::make::path_segment_ty(subst.clone(), trait_ref);
let qualified =
ast::make::path_from_segments(std::iter::once(segment), false);
let segment = make::path_segment_ty(subst.clone(), trait_ref);
let qualified = make::path_from_segments(std::iter::once(segment), false);
ted::replace(path.syntax(), qualified.clone_for_update().syntax());
} else if let Some(path_ty) = ast::PathType::cast(parent) {
ted::replace(

16
crates/ide-db/src/use_trivial_constructor.rs
View file

@ -1,31 +1,29 @@
//! Functionality for generating trivial constructors
use hir::StructKind;
use syntax::ast;
use syntax::ast::{make, Expr, Path};
/// given a type return the trivial constructor (if one exists)
pub fn use_trivial_constructor(
db: &crate::RootDatabase,
path: ast::Path,
path: Path,
ty: &hir::Type,
) -> Option<ast::Expr> {
) -> Option<Expr> {
match ty.as_adt() {
Some(hir::Adt::Enum(x)) => {
if let &[variant] = &*x.variants(db) {
if variant.kind(db) == hir::StructKind::Unit {
let path = ast::make::path_qualified(
let path = make::path_qualified(
path,
syntax::ast::make::path_segment(ast::make::name_ref(
&variant.name(db).to_smol_str(),
)),
make::path_segment(make::name_ref(&variant.name(db).to_smol_str())),
);
return Some(syntax::ast::make::expr_path(path));
return Some(make::expr_path(path));
}
}
}
Some(hir::Adt::Struct(x)) if x.kind(db) == StructKind::Unit => {
return Some(syntax::ast::make::expr_path(path));
return Some(make::expr_path(path));
}
_ => {}
}

2
crates/parser/src/grammar/generic_params.rs
View file

@ -88,7 +88,7 @@ fn const_param(p: &mut Parser<'_>, m: Marker) {
// test const_param_default_path
// struct A<const N: i32 = i32::MAX>;
generic_args::const_arg_expr(p);
generic_args::const_arg(p);
}
m.complete(p, CONST_PARAM);

6
crates/parser/test_data/parser/inline/err/0022_recover_from_missing_const_default.rast
View file

@ -20,7 +20,8 @@ SOURCE_FILE
IDENT "i32"
WHITESPACE " "
EQ "="
WHITESPACE " "
WHITESPACE " "
CONST_ARG
COMMA ","
WHITESPACE " "
CONST_PARAM
@ -37,8 +38,9 @@ SOURCE_FILE
IDENT "i32"
WHITESPACE " "
EQ "="
CONST_ARG
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"
error 23: expected a generic const argument
error 24: expected a generic const argument
error 40: expected a generic const argument

15
crates/parser/test_data/parser/inline/ok/0188_const_param_default_path.rast
View file

@ -21,16 +21,17 @@ SOURCE_FILE
WHITESPACE " "
EQ "="
WHITESPACE " "
PATH_EXPR
PATH
CONST_ARG
PATH_EXPR
PATH
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
COLON2 "::"
PATH_SEGMENT
NAME_REF
IDENT "i32"
COLON2 "::"
PATH_SEGMENT
NAME_REF
IDENT "MAX"
IDENT "MAX"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"

17
crates/parser/test_data/parser/inline/ok/0199_const_param_default_expression.rast
View file

@ -21,14 +21,15 @@ SOURCE_FILE
WHITESPACE " "
EQ "="
WHITESPACE " "
BLOCK_EXPR
STMT_LIST
L_CURLY "{"
WHITESPACE " "
LITERAL
INT_NUMBER "1"
WHITESPACE " "
R_CURLY "}"
CONST_ARG
BLOCK_EXPR
STMT_LIST
L_CURLY "{"
WHITESPACE " "
LITERAL
INT_NUMBER "1"
WHITESPACE " "
R_CURLY "}"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"

9
crates/parser/test_data/parser/inline/ok/0200_const_param_default_literal.rast
View file

@ -21,10 +21,11 @@ SOURCE_FILE
WHITESPACE " "
EQ "="
WHITESPACE " "
PREFIX_EXPR
MINUS "-"
LITERAL
INT_NUMBER "1"
CONST_ARG
PREFIX_EXPR
MINUS "-"
LITERAL
INT_NUMBER "1"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"

2
crates/syntax/rust.ungram
View file

@ -296,7 +296,7 @@ TypeParam =
ConstParam =
Attr* 'const' Name ':' Type
('=' default_val:Expr)?
('=' default_val:ConstArg)?
LifetimeParam =
Attr* Lifetime (':' TypeBoundList?)?

2
crates/syntax/src/ast/generated/nodes.rs
View file

@ -709,7 +709,7 @@ impl ConstParam {
pub fn colon_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![:]) }
pub fn ty(&self) -> Option<Type> { support::child(&self.syntax) }
pub fn eq_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![=]) }
pub fn default_val(&self) -> Option<Expr> { support::child(&self.syntax) }
pub fn default_val(&self) -> Option<ConstArg> { support::child(&self.syntax) }
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]

5
crates/syntax/src/ast/make.rs
View file

@ -503,11 +503,16 @@ pub fn hacky_block_expr(
pub fn expr_unit() -> ast::Expr {
expr_from_text("()")
}
pub fn expr_literal(text: &str) -> ast::Literal {
assert_eq!(text.trim(), text);
ast_from_text(&format!("fn f() {{ let _ = {text}; }}"))
}
pub fn expr_const_value(text: &str) -> ast::ConstArg {
ast_from_text(&format!("trait Foo<const N: usize = {text}> {{}}"))
}
pub fn expr_empty_block() -> ast::Expr {
expr_from_text("{}")
}