From fdaec57a28ab6a8cd60fd7a2842d366a9b452a2e Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Tue, 18 Jul 2023 17:03:22 +0200
Subject: [PATCH 1/6] XSimplifiedType to SimplifiedType::X
---
.../src/coherence/orphan.rs | 10 +-
compiler/rustc_middle/src/ty/fast_reject.rs | 112 +++++++++---------
.../src/solve/trait_goals.rs | 2 +-
src/librustdoc/clean/inline.rs | 4 +-
src/librustdoc/clean/types.rs | 51 ++++----
.../src/utils/internal_lints/invalid_paths.rs | 8 +-
src/tools/clippy/clippy_utils/src/lib.rs | 47 ++++----
7 files changed, 116 insertions(+), 118 deletions(-)
diff --git a/compiler/rustc_hir_analysis/src/coherence/orphan.rs b/compiler/rustc_hir_analysis/src/coherence/orphan.rs
index 05c78f5708814..21ffbefcd0810 100644
--- a/compiler/rustc_hir_analysis/src/coherence/orphan.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/orphan.rs
@@ -568,10 +568,10 @@ fn fast_reject_auto_impl<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, self_ty:
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for DisableAutoTraitVisitor<'tcx> {
type BreakTy = ();
- fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+ fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
let tcx = self.tcx;
- if t != self.self_ty_root {
- for impl_def_id in tcx.non_blanket_impls_for_ty(self.trait_def_id, t) {
+ if ty != self.self_ty_root {
+ for impl_def_id in tcx.non_blanket_impls_for_ty(self.trait_def_id, ty) {
match tcx.impl_polarity(impl_def_id) {
ImplPolarity::Negative => return ControlFlow::Break(()),
ImplPolarity::Reservation => {}
@@ -584,7 +584,7 @@ fn fast_reject_auto_impl<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, self_ty:
}
}
- match t.kind() {
+ match ty.kind() {
ty::Adt(def, args) if def.is_phantom_data() => args.visit_with(self),
ty::Adt(def, args) => {
// @lcnr: This is the only place where cycles can happen. We avoid this
@@ -599,7 +599,7 @@ fn fast_reject_auto_impl<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, self_ty:
ControlFlow::Continue(())
}
- _ => t.super_visit_with(self),
+ _ => ty.super_visit_with(self),
}
}
}
diff --git a/compiler/rustc_middle/src/ty/fast_reject.rs b/compiler/rustc_middle/src/ty/fast_reject.rs
index e86ff4d26aaab..deb4dcf1f760a 100644
--- a/compiler/rustc_middle/src/ty/fast_reject.rs
+++ b/compiler/rustc_middle/src/ty/fast_reject.rs
@@ -6,35 +6,33 @@ use std::fmt::Debug;
use std::hash::Hash;
use std::iter;
-use self::SimplifiedType::*;
-
/// See `simplify_type`.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
pub enum SimplifiedType {
- BoolSimplifiedType,
- CharSimplifiedType,
- IntSimplifiedType(ty::IntTy),
- UintSimplifiedType(ty::UintTy),
- FloatSimplifiedType(ty::FloatTy),
- AdtSimplifiedType(DefId),
- ForeignSimplifiedType(DefId),
- StrSimplifiedType,
- ArraySimplifiedType,
- SliceSimplifiedType,
- RefSimplifiedType(Mutability),
- PtrSimplifiedType(Mutability),
- NeverSimplifiedType,
- TupleSimplifiedType(usize),
+ Bool,
+ Char,
+ Int(ty::IntTy),
+ Uint(ty::UintTy),
+ Float(ty::FloatTy),
+ Adt(DefId),
+ Foreign(DefId),
+ Str,
+ Array,
+ Slice,
+ Ref(Mutability),
+ Ptr(Mutability),
+ Never,
+ Tuple(usize),
/// A trait object, all of whose components are markers
/// (e.g., `dyn Send + Sync`).
- MarkerTraitObjectSimplifiedType,
- TraitSimplifiedType(DefId),
- ClosureSimplifiedType(DefId),
- GeneratorSimplifiedType(DefId),
- GeneratorWitnessSimplifiedType(usize),
- GeneratorWitnessMIRSimplifiedType(DefId),
- FunctionSimplifiedType(usize),
- PlaceholderSimplifiedType,
+ MarkerTraitObject,
+ Trait(DefId),
+ Closure(DefId),
+ Generator(DefId),
+ GeneratorWitness(usize),
+ GeneratorWitnessMIR(DefId),
+ Function(usize),
+ Placeholder,
}
/// Generic parameters are pretty much just bound variables, e.g.
@@ -110,34 +108,36 @@ pub fn simplify_type<'tcx>(
treat_params: TreatParams,
) -> Option<SimplifiedType> {
match *ty.kind() {
- ty::Bool => Some(BoolSimplifiedType),
- ty::Char => Some(CharSimplifiedType),
- ty::Int(int_type) => Some(IntSimplifiedType(int_type)),
- ty::Uint(uint_type) => Some(UintSimplifiedType(uint_type)),
- ty::Float(float_type) => Some(FloatSimplifiedType(float_type)),
- ty::Adt(def, _) => Some(AdtSimplifiedType(def.did())),
- ty::Str => Some(StrSimplifiedType),
- ty::Array(..) => Some(ArraySimplifiedType),
- ty::Slice(..) => Some(SliceSimplifiedType),
- ty::RawPtr(ptr) => Some(PtrSimplifiedType(ptr.mutbl)),
+ ty::Bool => Some(SimplifiedType::Bool),
+ ty::Char => Some(SimplifiedType::Char),
+ ty::Int(int_type) => Some(SimplifiedType::Int(int_type)),
+ ty::Uint(uint_type) => Some(SimplifiedType::Uint(uint_type)),
+ ty::Float(float_type) => Some(SimplifiedType::Float(float_type)),
+ ty::Adt(def, _) => Some(SimplifiedType::Adt(def.did())),
+ ty::Str => Some(SimplifiedType::Str),
+ ty::Array(..) => Some(SimplifiedType::Array),
+ ty::Slice(..) => Some(SimplifiedType::Slice),
+ ty::RawPtr(ptr) => Some(SimplifiedType::Ptr(ptr.mutbl)),
ty::Dynamic(trait_info, ..) => match trait_info.principal_def_id() {
Some(principal_def_id) if !tcx.trait_is_auto(principal_def_id) => {
- Some(TraitSimplifiedType(principal_def_id))
+ Some(SimplifiedType::Trait(principal_def_id))
}
- _ => Some(MarkerTraitObjectSimplifiedType),
+ _ => Some(SimplifiedType::MarkerTraitObject),
},
- ty::Ref(_, _, mutbl) => Some(RefSimplifiedType(mutbl)),
- ty::FnDef(def_id, _) | ty::Closure(def_id, _) => Some(ClosureSimplifiedType(def_id)),
- ty::Generator(def_id, _, _) => Some(GeneratorSimplifiedType(def_id)),
- ty::GeneratorWitness(tys) => Some(GeneratorWitnessSimplifiedType(tys.skip_binder().len())),
- ty::GeneratorWitnessMIR(def_id, _) => Some(GeneratorWitnessMIRSimplifiedType(def_id)),
- ty::Never => Some(NeverSimplifiedType),
- ty::Tuple(tys) => Some(TupleSimplifiedType(tys.len())),
- ty::FnPtr(f) => Some(FunctionSimplifiedType(f.skip_binder().inputs().len())),
- ty::Placeholder(..) => Some(PlaceholderSimplifiedType),
+ ty::Ref(_, _, mutbl) => Some(SimplifiedType::Ref(mutbl)),
+ ty::FnDef(def_id, _) | ty::Closure(def_id, _) => Some(SimplifiedType::Closure(def_id)),
+ ty::Generator(def_id, _, _) => Some(SimplifiedType::Generator(def_id)),
+ ty::GeneratorWitness(tys) => {
+ Some(SimplifiedType::GeneratorWitness(tys.skip_binder().len()))
+ }
+ ty::GeneratorWitnessMIR(def_id, _) => Some(SimplifiedType::GeneratorWitnessMIR(def_id)),
+ ty::Never => Some(SimplifiedType::Never),
+ ty::Tuple(tys) => Some(SimplifiedType::Tuple(tys.len())),
+ ty::FnPtr(f) => Some(SimplifiedType::Function(f.skip_binder().inputs().len())),
+ ty::Placeholder(..) => Some(SimplifiedType::Placeholder),
ty::Param(_) => match treat_params {
TreatParams::ForLookup | TreatParams::NextSolverLookup => {
- Some(PlaceholderSimplifiedType)
+ Some(SimplifiedType::Placeholder)
}
TreatParams::AsCandidateKey => None,
},
@@ -147,11 +147,13 @@ pub fn simplify_type<'tcx>(
//
// We will have to be careful with lazy normalization here.
// FIXME(lazy_normalization): This is probably not right...
- TreatParams::ForLookup if !ty.has_non_region_infer() => Some(PlaceholderSimplifiedType),
- TreatParams::NextSolverLookup => Some(PlaceholderSimplifiedType),
+ TreatParams::ForLookup if !ty.has_non_region_infer() => {
+ Some(SimplifiedType::Placeholder)
+ }
+ TreatParams::NextSolverLookup => Some(SimplifiedType::Placeholder),
TreatParams::ForLookup | TreatParams::AsCandidateKey => None,
},
- ty::Foreign(def_id) => Some(ForeignSimplifiedType(def_id)),
+ ty::Foreign(def_id) => Some(SimplifiedType::Foreign(def_id)),
ty::Bound(..) | ty::Infer(_) | ty::Error(_) => None,
}
}
@@ -159,12 +161,12 @@ pub fn simplify_type<'tcx>(
impl SimplifiedType {
pub fn def(self) -> Option<DefId> {
match self {
- AdtSimplifiedType(d)
- | ForeignSimplifiedType(d)
- | TraitSimplifiedType(d)
- | ClosureSimplifiedType(d)
- | GeneratorSimplifiedType(d)
- | GeneratorWitnessMIRSimplifiedType(d) => Some(d),
+ SimplifiedType::Adt(d)
+ | SimplifiedType::Foreign(d)
+ | SimplifiedType::Trait(d)
+ | SimplifiedType::Closure(d)
+ | SimplifiedType::Generator(d)
+ | SimplifiedType::GeneratorWitnessMIR(d) => Some(d),
_ => None,
}
}
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index e7867eead1597..29889614620dd 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -686,7 +686,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
| ty::Tuple(_)
| ty::Adt(_, _)
// FIXME: Handling opaques here is kinda sus. Especially because we
- // simplify them to PlaceholderSimplifiedType.
+ // simplify them to SimplifiedType::Placeholder.
| ty::Alias(ty::Opaque, _) => {
let mut disqualifying_impl = None;
self.tcx().for_each_relevant_impl_treating_projections(
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 5e2e2d2495000..cfd9875e1c8fa 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -12,6 +12,7 @@ use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::{DefId, DefIdSet, LocalDefId};
use rustc_hir::Mutability;
use rustc_metadata::creader::{CStore, LoadedMacro};
+use rustc_middle::ty::fast_reject::SimplifiedType;
use rustc_middle::ty::{self, TyCtxt};
use rustc_span::hygiene::MacroKind;
use rustc_span::symbol::{kw, sym, Symbol};
@@ -314,9 +315,8 @@ pub(crate) fn build_impls(
// * https://github.com/rust-lang/rust/pull/99917 — where the feature got used
// * https://github.com/rust-lang/rust/issues/53487 — overall tracking issue for Error
if tcx.has_attr(did, sym::rustc_has_incoherent_inherent_impls) {
- use rustc_middle::ty::fast_reject::SimplifiedType::*;
let type_ =
- if tcx.is_trait(did) { TraitSimplifiedType(did) } else { AdtSimplifiedType(did) };
+ if tcx.is_trait(did) { SimplifiedType::Trait(did) } else { SimplifiedType::Adt(did) };
for &did in tcx.incoherent_impls(type_) {
build_impl(cx, did, attrs, ret);
}
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index cfe62407fd35d..ddef165a05479 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -1776,7 +1776,6 @@ impl PrimitiveType {
}
pub(crate) fn simplified_types() -> &'static SimplifiedTypes {
- use ty::fast_reject::SimplifiedType::*;
use ty::{FloatTy, IntTy, UintTy};
use PrimitiveType::*;
static CELL: OnceCell<SimplifiedTypes> = OnceCell::new();
@@ -1784,38 +1783,38 @@ impl PrimitiveType {
let single = |x| iter::once(x).collect();
CELL.get_or_init(move || {
map! {
- Isize => single(IntSimplifiedType(IntTy::Isize)),
- I8 => single(IntSimplifiedType(IntTy::I8)),
- I16 => single(IntSimplifiedType(IntTy::I16)),
- I32 => single(IntSimplifiedType(IntTy::I32)),
- I64 => single(IntSimplifiedType(IntTy::I64)),
- I128 => single(IntSimplifiedType(IntTy::I128)),
- Usize => single(UintSimplifiedType(UintTy::Usize)),
- U8 => single(UintSimplifiedType(UintTy::U8)),
- U16 => single(UintSimplifiedType(UintTy::U16)),
- U32 => single(UintSimplifiedType(UintTy::U32)),
- U64 => single(UintSimplifiedType(UintTy::U64)),
- U128 => single(UintSimplifiedType(UintTy::U128)),
- F32 => single(FloatSimplifiedType(FloatTy::F32)),
- F64 => single(FloatSimplifiedType(FloatTy::F64)),
- Str => single(StrSimplifiedType),
- Bool => single(BoolSimplifiedType),
- Char => single(CharSimplifiedType),
- Array => single(ArraySimplifiedType),
- Slice => single(SliceSimplifiedType),
+ Isize => single(SimplifiedType::Int(IntTy::Isize)),
+ I8 => single(SimplifiedType::Int(IntTy::I8)),
+ I16 => single(SimplifiedType::Int(IntTy::I16)),
+ I32 => single(SimplifiedType::Int(IntTy::I32)),
+ I64 => single(SimplifiedType::Int(IntTy::I64)),
+ I128 => single(SimplifiedType::Int(IntTy::I128)),
+ Usize => single(SimplifiedType::Uint(UintTy::Usize)),
+ U8 => single(SimplifiedType::Uint(UintTy::U8)),
+ U16 => single(SimplifiedType::Uint(UintTy::U16)),
+ U32 => single(SimplifiedType::Uint(UintTy::U32)),
+ U64 => single(SimplifiedType::Uint(UintTy::U64)),
+ U128 => single(SimplifiedType::Uint(UintTy::U128)),
+ F32 => single(SimplifiedType::Float(FloatTy::F32)),
+ F64 => single(SimplifiedType::Float(FloatTy::F64)),
+ Str => single(SimplifiedType::Str),
+ Bool => single(SimplifiedType::Bool),
+ Char => single(SimplifiedType::Char),
+ Array => single(SimplifiedType::Array),
+ Slice => single(SimplifiedType::Slice),
// FIXME: If we ever add an inherent impl for tuples
// with different lengths, they won't show in rustdoc.
//
// Either manually update this arrayvec at this point
// or start with a more complex refactoring.
- Tuple => [TupleSimplifiedType(1), TupleSimplifiedType(2), TupleSimplifiedType(3)].into(),
- Unit => single(TupleSimplifiedType(0)),
- RawPointer => [PtrSimplifiedType(Mutability::Not), PtrSimplifiedType(Mutability::Mut)].into_iter().collect(),
- Reference => [RefSimplifiedType(Mutability::Not), RefSimplifiedType(Mutability::Mut)].into_iter().collect(),
+ Tuple => [SimplifiedType::Tuple(1), SimplifiedType::Tuple(2), SimplifiedType::Tuple(3)].into(),
+ Unit => single(SimplifiedType::Tuple(0)),
+ RawPointer => [SimplifiedType::Ptr(Mutability::Not), SimplifiedType::Ptr(Mutability::Mut)].into_iter().collect(),
+ Reference => [SimplifiedType::Ref(Mutability::Not), SimplifiedType::Ref(Mutability::Mut)].into_iter().collect(),
// FIXME: This will be wrong if we ever add inherent impls
// for function pointers.
- Fn => single(FunctionSimplifiedType(1)),
- Never => single(NeverSimplifiedType),
+ Fn => single(SimplifiedType::Function(1)),
+ Never => single(SimplifiedType::Never),
}
})
}
diff --git a/src/tools/clippy/clippy_lints/src/utils/internal_lints/invalid_paths.rs b/src/tools/clippy/clippy_lints/src/utils/internal_lints/invalid_paths.rs
index 94b56304bcab4..e4906944c8d0a 100644
--- a/src/tools/clippy/clippy_lints/src/utils/internal_lints/invalid_paths.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/internal_lints/invalid_paths.rs
@@ -74,10 +74,10 @@ pub fn check_path(cx: &LateContext<'_>, path: &[&str]) -> bool {
let lang_items = cx.tcx.lang_items();
// This list isn't complete, but good enough for our current list of paths.
let incoherent_impls = [
- SimplifiedType::FloatSimplifiedType(FloatTy::F32),
- SimplifiedType::FloatSimplifiedType(FloatTy::F64),
- SimplifiedType::SliceSimplifiedType,
- SimplifiedType::StrSimplifiedType,
+ SimplifiedType::Float(FloatTy::F32),
+ SimplifiedType::Float(FloatTy::F64),
+ SimplifiedType::Slice,
+ SimplifiedType::Str,
]
.iter()
.flat_map(|&ty| cx.tcx.incoherent_impls(ty).iter().copied());
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 00e893fbdda8b..035511e891258 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -100,10 +100,7 @@ use rustc_middle::mir::ConstantKind;
use rustc_middle::ty as rustc_ty;
use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
use rustc_middle::ty::binding::BindingMode;
-use rustc_middle::ty::fast_reject::SimplifiedType::{
- ArraySimplifiedType, BoolSimplifiedType, CharSimplifiedType, FloatSimplifiedType, IntSimplifiedType,
- PtrSimplifiedType, SliceSimplifiedType, StrSimplifiedType, UintSimplifiedType,
-};
+use rustc_middle::ty::fast_reject::SimplifiedType;
use rustc_middle::ty::layout::IntegerExt;
use rustc_middle::ty::{
BorrowKind, ClosureKind, FloatTy, IntTy, Ty, TyCtxt, TypeAndMut, TypeVisitableExt, UintTy, UpvarCapture,
@@ -512,30 +509,30 @@ pub fn path_def_id<'tcx>(cx: &LateContext<'_>, maybe_path: &impl MaybePath<'tcx>
fn find_primitive_impls<'tcx>(tcx: TyCtxt<'tcx>, name: &str) -> impl Iterator<Item = DefId> + 'tcx {
let ty = match name {
- "bool" => BoolSimplifiedType,
- "char" => CharSimplifiedType,
- "str" => StrSimplifiedType,
- "array" => ArraySimplifiedType,
- "slice" => SliceSimplifiedType,
+ "bool" => SimplifiedType::Bool,
+ "char" => SimplifiedType::Char,
+ "str" => SimplifiedType::Str,
+ "array" => SimplifiedType::Array,
+ "slice" => SimplifiedType::Slice,
// FIXME: rustdoc documents these two using just `pointer`.
//
// Maybe this is something we should do here too.
- "const_ptr" => PtrSimplifiedType(Mutability::Not),
- "mut_ptr" => PtrSimplifiedType(Mutability::Mut),
- "isize" => IntSimplifiedType(IntTy::Isize),
- "i8" => IntSimplifiedType(IntTy::I8),
- "i16" => IntSimplifiedType(IntTy::I16),
- "i32" => IntSimplifiedType(IntTy::I32),
- "i64" => IntSimplifiedType(IntTy::I64),
- "i128" => IntSimplifiedType(IntTy::I128),
- "usize" => UintSimplifiedType(UintTy::Usize),
- "u8" => UintSimplifiedType(UintTy::U8),
- "u16" => UintSimplifiedType(UintTy::U16),
- "u32" => UintSimplifiedType(UintTy::U32),
- "u64" => UintSimplifiedType(UintTy::U64),
- "u128" => UintSimplifiedType(UintTy::U128),
- "f32" => FloatSimplifiedType(FloatTy::F32),
- "f64" => FloatSimplifiedType(FloatTy::F64),
+ "const_ptr" => SimplifiedType::Ptr(Mutability::Not),
+ "mut_ptr" => SimplifiedType::Ptr(Mutability::Mut),
+ "isize" => SimplifiedType::Int(IntTy::Isize),
+ "i8" => SimplifiedType::Int(IntTy::I8),
+ "i16" => SimplifiedType::Int(IntTy::I16),
+ "i32" => SimplifiedType::Int(IntTy::I32),
+ "i64" => SimplifiedType::Int(IntTy::I64),
+ "i128" => SimplifiedType::Int(IntTy::I128),
+ "usize" => SimplifiedType::Uint(UintTy::Usize),
+ "u8" => SimplifiedType::Uint(UintTy::U8),
+ "u16" => SimplifiedType::Uint(UintTy::U16),
+ "u32" => SimplifiedType::Uint(UintTy::U32),
+ "u64" => SimplifiedType::Uint(UintTy::U64),
+ "u128" => SimplifiedType::Uint(UintTy::U128),
+ "f32" => SimplifiedType::Float(FloatTy::F32),
+ "f64" => SimplifiedType::Float(FloatTy::F64),
_ => return [].iter().copied(),
};
From 2d99f40ec5ee10df8f7325e4e71d8249f8dacd92 Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Tue, 18 Jul 2023 18:07:42 +0200
Subject: [PATCH 2/6] assembly: only consider blanket impls once
---
.../src/solve/assembly/mod.rs | 273 +++++++++++++-----
.../src/solve/project_goals.rs | 12 +-
.../src/solve/trait_goals.rs | 9 +-
...mble-normalizing-self-ty-impl-ambiguity.rs | 25 ++
...-normalizing-self-ty-impl-ambiguity.stderr | 23 ++
5 files changed, 274 insertions(+), 68 deletions(-)
create mode 100644 tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
create mode 100644 tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index 1e79899889551..73cf15ff94b59 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -10,9 +10,11 @@ use rustc_infer::traits::util::elaborate;
use rustc_infer::traits::Reveal;
use rustc_middle::traits::solve::inspect::CandidateKind;
use rustc_middle::traits::solve::{CanonicalResponse, Certainty, Goal, MaybeCause, QueryResult};
-use rustc_middle::ty::fast_reject::TreatProjections;
-use rustc_middle::ty::TypeFoldable;
+use rustc_middle::ty::fast_reject::{SimplifiedType, TreatParams};
+use rustc_middle::ty::TypeVisitableExt;
use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{fast_reject, TypeFoldable};
+use rustc_span::ErrorGuaranteed;
use std::fmt::Debug;
pub(super) mod structural_traits;
@@ -109,10 +111,10 @@ pub(super) trait GoalKind<'tcx>:
fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId;
- // Try equating an assumption predicate against a goal's predicate. If it
- // holds, then execute the `then` callback, which should do any additional
- // work, then produce a response (typically by executing
- // [`EvalCtxt::evaluate_added_goals_and_make_canonical_response`]).
+ /// Try equating an assumption predicate against a goal's predicate. If it
+ /// holds, then execute the `then` callback, which should do any additional
+ /// work, then produce a response (typically by executing
+ /// [`EvalCtxt::evaluate_added_goals_and_make_canonical_response`]).
fn probe_and_match_goal_against_assumption(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
@@ -120,9 +122,9 @@ pub(super) trait GoalKind<'tcx>:
then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>,
) -> QueryResult<'tcx>;
- // Consider a clause, which consists of a "assumption" and some "requirements",
- // to satisfy a goal. If the requirements hold, then attempt to satisfy our
- // goal by equating it with the assumption.
+ /// Consider a clause, which consists of a "assumption" and some "requirements",
+ /// to satisfy a goal. If the requirements hold, then attempt to satisfy our
+ /// goal by equating it with the assumption.
fn consider_implied_clause(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
@@ -149,9 +151,9 @@ pub(super) trait GoalKind<'tcx>:
})
}
- // Consider a clause specifically for a `dyn Trait` self type. This requires
- // additionally checking all of the supertraits and object bounds to hold,
- // since they're not implied by the well-formedness of the object type.
+ /// Consider a clause specifically for a `dyn Trait` self type. This requires
+ /// additionally checking all of the supertraits and object bounds to hold,
+ /// since they're not implied by the well-formedness of the object type.
fn consider_object_bound_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
@@ -182,96 +184,106 @@ pub(super) trait GoalKind<'tcx>:
impl_def_id: DefId,
) -> QueryResult<'tcx>;
- // A type implements an `auto trait` if its components do as well. These components
- // are given by built-in rules from [`instantiate_constituent_tys_for_auto_trait`].
+ /// If the predicate contained an error, we want to avoid emitting unnecessary trait errors but
+ /// still want to emit errors for other trait goals. We have some special handling for this case.
+ ///
+ /// Trait goals always hold while projection goals never do. This is a bit arbitrary but prevents
+ /// incorrect normalization while hiding any trait errors.
+ fn consider_error_guaranteed_candidate(
+ ecx: &mut EvalCtxt<'_, 'tcx>,
+ guar: ErrorGuaranteed,
+ ) -> QueryResult<'tcx>;
+
+ /// A type implements an `auto trait` if its components do as well. These components
+ /// are given by built-in rules from [`instantiate_constituent_tys_for_auto_trait`].
fn consider_auto_trait_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A trait alias holds if the RHS traits and `where` clauses hold.
+ /// A trait alias holds if the RHS traits and `where` clauses hold.
fn consider_trait_alias_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A type is `Copy` or `Clone` if its components are `Sized`. These components
- // are given by built-in rules from [`instantiate_constituent_tys_for_sized_trait`].
+ /// A type is `Copy` or `Clone` if its components are `Sized`. These components
+ /// are given by built-in rules from [`instantiate_constituent_tys_for_sized_trait`].
fn consider_builtin_sized_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A type is `Copy` or `Clone` if its components are `Copy` or `Clone`. These
- // components are given by built-in rules from [`instantiate_constituent_tys_for_copy_clone_trait`].
+ /// A type is `Copy` or `Clone` if its components are `Copy` or `Clone`. These
+ /// components are given by built-in rules from [`instantiate_constituent_tys_for_copy_clone_trait`].
fn consider_builtin_copy_clone_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A type is `PointerLike` if we can compute its layout, and that layout
- // matches the layout of `usize`.
+ /// A type is `PointerLike` if we can compute its layout, and that layout
+ /// matches the layout of `usize`.
fn consider_builtin_pointer_like_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A type is a `FnPtr` if it is of `FnPtr` type.
+ /// A type is a `FnPtr` if it is of `FnPtr` type.
fn consider_builtin_fn_ptr_trait_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A callable type (a closure, fn def, or fn ptr) is known to implement the `Fn<A>`
- // family of traits where `A` is given by the signature of the type.
+ /// A callable type (a closure, fn def, or fn ptr) is known to implement the `Fn<A>`
+ /// family of traits where `A` is given by the signature of the type.
fn consider_builtin_fn_trait_candidates(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
kind: ty::ClosureKind,
) -> QueryResult<'tcx>;
- // `Tuple` is implemented if the `Self` type is a tuple.
+ /// `Tuple` is implemented if the `Self` type is a tuple.
fn consider_builtin_tuple_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // `Pointee` is always implemented.
- //
- // See the projection implementation for the `Metadata` types for all of
- // the built-in types. For structs, the metadata type is given by the struct
- // tail.
+ /// `Pointee` is always implemented.
+ ///
+ /// See the projection implementation for the `Metadata` types for all of
+ /// the built-in types. For structs, the metadata type is given by the struct
+ /// tail.
fn consider_builtin_pointee_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A generator (that comes from an `async` desugaring) is known to implement
- // `Future<Output = O>`, where `O` is given by the generator's return type
- // that was computed during type-checking.
+ /// A generator (that comes from an `async` desugaring) is known to implement
+ /// `Future<Output = O>`, where `O` is given by the generator's return type
+ /// that was computed during type-checking.
fn consider_builtin_future_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // A generator (that doesn't come from an `async` desugaring) is known to
- // implement `Generator<R, Yield = Y, Return = O>`, given the resume, yield,
- // and return types of the generator computed during type-checking.
+ /// A generator (that doesn't come from an `async` desugaring) is known to
+ /// implement `Generator<R, Yield = Y, Return = O>`, given the resume, yield,
+ /// and return types of the generator computed during type-checking.
fn consider_builtin_generator_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // The most common forms of unsizing are array to slice, and concrete (Sized)
- // type into a `dyn Trait`. ADTs and Tuples can also have their final field
- // unsized if it's generic.
+ /// The most common forms of unsizing are array to slice, and concrete (Sized)
+ /// type into a `dyn Trait`. ADTs and Tuples can also have their final field
+ /// unsized if it's generic.
fn consider_builtin_unsize_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- // `dyn Trait1` can be unsized to `dyn Trait2` if they are the same trait, or
- // if `Trait2` is a (transitive) supertrait of `Trait2`.
+ /// `dyn Trait1` can be unsized to `dyn Trait2` if they are the same trait, or
+ /// if `Trait2` is a (transitive) supertrait of `Trait2`.
fn consider_builtin_dyn_upcast_candidates(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
@@ -299,35 +311,60 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
goal: Goal<'tcx, G>,
) -> Vec<Candidate<'tcx>> {
debug_assert_eq!(goal, self.resolve_vars_if_possible(goal));
+ if let Some(ambig) = self.self_ty_infer_ambiguity_hack(goal) {
+ return ambig;
+ }
+
+ let mut candidates = self.assemble_candidates_via_self_ty(goal);
+
+ self.assemble_blanket_impl_candidates(goal, &mut candidates);
+
+ self.assemble_param_env_candidates(goal, &mut candidates);
- // HACK: `_: Trait` is ambiguous, because it may be satisfied via a builtin rule,
- // object bound, alias bound, etc. We are unable to determine this until we can at
- // least structurally resolve the type one layer.
- if goal.predicate.self_ty().is_ty_var() {
- return vec![Candidate {
+ candidates
+ }
+
+ fn self_ty_infer_ambiguity_hack<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ ) -> Option<Vec<Candidate<'tcx>>> {
+ goal.predicate.self_ty().is_ty_var().then(|| {
+ vec![Candidate {
source: CandidateSource::BuiltinImpl(BuiltinImplSource::Ambiguity),
result: self
.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
.unwrap(),
- }];
+ }]
+ })
+ }
+
+ /// Assemble candidates which apply to the self type. This only looks at candidate which
+ /// apply to the specific self type and ignores all others.
+ ///
+ /// Returns `None` if the self type is still ambiguous.
+ fn assemble_candidates_via_self_ty<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ ) -> Vec<Candidate<'tcx>> {
+ debug_assert_eq!(goal, self.resolve_vars_if_possible(goal));
+ if let Some(ambig) = self.self_ty_infer_ambiguity_hack(goal) {
+ return ambig;
}
let mut candidates = Vec::new();
- self.assemble_candidates_after_normalizing_self_ty(goal, &mut candidates);
-
- self.assemble_impl_candidates(goal, &mut candidates);
+ self.assemble_non_blanket_impl_candidates(goal, &mut candidates);
self.assemble_builtin_impl_candidates(goal, &mut candidates);
- self.assemble_param_env_candidates(goal, &mut candidates);
-
self.assemble_alias_bound_candidates(goal, &mut candidates);
self.assemble_object_bound_candidates(goal, &mut candidates);
self.assemble_coherence_unknowable_candidates(goal, &mut candidates);
+ self.assemble_candidates_after_normalizing_self_ty(goal, &mut candidates);
+
candidates
}
@@ -385,7 +422,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
// have a `Normalized` candidate. This doesn't work as long as we
// use `CandidateSource` in winnowing.
let goal = goal.with(tcx, goal.predicate.with_self_ty(tcx, normalized_ty));
- Ok(ecx.assemble_and_evaluate_candidates(goal))
+ Ok(ecx.assemble_candidates_via_self_ty(goal))
},
)
});
@@ -396,22 +433,125 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
}
#[instrument(level = "debug", skip_all)]
- fn assemble_impl_candidates<G: GoalKind<'tcx>>(
+ fn assemble_non_blanket_impl_candidates<G: GoalKind<'tcx>>(
&mut self,
goal: Goal<'tcx, G>,
candidates: &mut Vec<Candidate<'tcx>>,
) {
let tcx = self.tcx();
- tcx.for_each_relevant_impl_treating_projections(
- goal.predicate.trait_def_id(tcx),
- goal.predicate.self_ty(),
- TreatProjections::NextSolverLookup,
- |impl_def_id| match G::consider_impl_candidate(self, goal, impl_def_id) {
+ let self_ty = goal.predicate.self_ty();
+ let trait_impls = tcx.trait_impls_of(goal.predicate.trait_def_id(tcx));
+ let mut consider_impls_for_simplified_type = |simp| {
+ if let Some(impls_for_type) = trait_impls.non_blanket_impls().get(&simp) {
+ for &impl_def_id in impls_for_type {
+ match G::consider_impl_candidate(self, goal, impl_def_id) {
+ Ok(result) => candidates
+ .push(Candidate { source: CandidateSource::Impl(impl_def_id), result }),
+ Err(NoSolution) => (),
+ }
+ }
+ }
+ };
+
+ match self_ty.kind() {
+ ty::Bool
+ | ty::Char
+ | ty::Int(_)
+ | ty::Uint(_)
+ | ty::Float(_)
+ | ty::Adt(_, _)
+ | ty::Foreign(_)
+ | ty::Str
+ | ty::Array(_, _)
+ | ty::Slice(_)
+ | ty::RawPtr(_)
+ | ty::Ref(_, _, _)
+ | ty::FnDef(_, _)
+ | ty::FnPtr(_)
+ | ty::Dynamic(_, _, _)
+ | ty::Closure(_, _)
+ | ty::Generator(_, _, _)
+ | ty::Never
+ | ty::Tuple(_) => {
+ let simp =
+ fast_reject::simplify_type(tcx, self_ty, TreatParams::ForLookup).unwrap();
+ consider_impls_for_simplified_type(simp);
+ }
+
+ // HACK: For integer and float variables we have to manually look at all impls
+ // which have some integer or float as a self type.
+ ty::Infer(ty::IntVar(_)) => {
+ use ty::IntTy::*;
+ use ty::UintTy::*;
+ // This causes a compiler error if any new integer kinds are added.
+ let (I8 | I16 | I32 | I64 | I128 | Isize): ty::IntTy;
+ let (U8 | U16 | U32 | U64 | U128 | Usize): ty::UintTy;
+ let possible_integers = [
+ // signed integers
+ SimplifiedType::Int(I8),
+ SimplifiedType::Int(I16),
+ SimplifiedType::Int(I32),
+ SimplifiedType::Int(I64),
+ SimplifiedType::Int(I128),
+ SimplifiedType::Int(Isize),
+ // unsigned integers
+ SimplifiedType::Uint(U8),
+ SimplifiedType::Uint(U16),
+ SimplifiedType::Uint(U32),
+ SimplifiedType::Uint(U64),
+ SimplifiedType::Uint(U128),
+ SimplifiedType::Uint(Usize),
+ ];
+ for simp in possible_integers {
+ consider_impls_for_simplified_type(simp);
+ }
+ }
+
+ ty::Infer(ty::FloatVar(_)) => {
+ // This causes a compiler error if any new float kinds are added.
+ let (ty::FloatTy::F32 | ty::FloatTy::F64);
+ let possible_floats = [
+ SimplifiedType::Float(ty::FloatTy::F32),
+ SimplifiedType::Float(ty::FloatTy::F64),
+ ];
+
+ for simp in possible_floats {
+ consider_impls_for_simplified_type(simp);
+ }
+ }
+
+ // The only traits applying to aliases and placeholders are blanket impls.
+ //
+ // Impls which apply to an alias after normalization are handled by
+ // `assemble_candidates_after_normalizing_self_ty`.
+ ty::Alias(_, _) | ty::Placeholder(..) | ty::Error(_) => (),
+
+ // FIXME: These should ideally not exist as a self type. It would be nice for
+ // the builtin auto trait impls of generators should instead directly recurse
+ // into the witness.
+ ty::GeneratorWitness(_) | ty::GeneratorWitnessMIR(_, _) => (),
+
+ // These variants should not exist as a self type.
+ ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_))
+ | ty::Param(_)
+ | ty::Bound(_, _) => bug!("unexpected self type: {self_ty}"),
+ }
+ }
+
+ fn assemble_blanket_impl_candidates<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ candidates: &mut Vec<Candidate<'tcx>>,
+ ) {
+ let tcx = self.tcx();
+ let trait_impls = tcx.trait_impls_of(goal.predicate.trait_def_id(tcx));
+ for &impl_def_id in trait_impls.blanket_impls() {
+ match G::consider_impl_candidate(self, goal, impl_def_id) {
Ok(result) => candidates
.push(Candidate { source: CandidateSource::Impl(impl_def_id), result }),
Err(NoSolution) => (),
- },
- );
+ }
+ }
}
#[instrument(level = "debug", skip_all)]
@@ -420,8 +560,9 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
goal: Goal<'tcx, G>,
candidates: &mut Vec<Candidate<'tcx>>,
) {
- let lang_items = self.tcx().lang_items();
- let trait_def_id = goal.predicate.trait_def_id(self.tcx());
+ let tcx = self.tcx();
+ let lang_items = tcx.lang_items();
+ let trait_def_id = goal.predicate.trait_def_id(tcx);
// N.B. When assembling built-in candidates for lang items that are also
// `auto` traits, then the auto trait candidate that is assembled in
@@ -430,9 +571,11 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
// Instead of adding the logic here, it's a better idea to add it in
// `EvalCtxt::disqualify_auto_trait_candidate_due_to_possible_impl` in
// `solve::trait_goals` instead.
- let result = if self.tcx().trait_is_auto(trait_def_id) {
+ let result = if let Err(guar) = goal.predicate.error_reported() {
+ G::consider_error_guaranteed_candidate(self, guar)
+ } else if tcx.trait_is_auto(trait_def_id) {
G::consider_auto_trait_candidate(self, goal)
- } else if self.tcx().trait_is_alias(trait_def_id) {
+ } else if tcx.trait_is_alias(trait_def_id) {
G::consider_trait_alias_candidate(self, goal)
} else if lang_items.sized_trait() == Some(trait_def_id) {
G::consider_builtin_sized_candidate(self, goal)
diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs
index d677fbdc7f425..222ed9939ba24 100644
--- a/compiler/rustc_trait_selection/src/solve/project_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs
@@ -2,7 +2,6 @@ use crate::traits::specialization_graph;
use super::assembly::{self, structural_traits};
use super::EvalCtxt;
-use rustc_errors::ErrorGuaranteed;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId;
use rustc_hir::LangItem;
@@ -15,7 +14,7 @@ use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
use rustc_middle::ty::ProjectionPredicate;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_middle::ty::{ToPredicate, TypeVisitableExt};
-use rustc_span::{sym, DUMMY_SP};
+use rustc_span::{sym, ErrorGuaranteed, DUMMY_SP};
impl<'tcx> EvalCtxt<'_, 'tcx> {
#[instrument(level = "debug", skip(self), ret)]
@@ -246,6 +245,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
})
}
+ /// Fail to normalize if the predicate contains an error, alternatively, we could normalize to `ty::Error`
+ /// and succeed. Can experiment with this to figure out what results in better error messages.
+ fn consider_error_guaranteed_candidate(
+ _ecx: &mut EvalCtxt<'_, 'tcx>,
+ _guar: ErrorGuaranteed,
+ ) -> QueryResult<'tcx> {
+ Err(NoSolution)
+ }
+
fn consider_auto_trait_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index 29889614620dd..930e62d638831 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -11,7 +11,7 @@ use rustc_middle::traits::Reveal;
use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams, TreatProjections};
use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt};
use rustc_middle::ty::{TraitPredicate, TypeVisitableExt};
-use rustc_span::DUMMY_SP;
+use rustc_span::{ErrorGuaranteed, DUMMY_SP};
impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
fn self_ty(self) -> Ty<'tcx> {
@@ -78,6 +78,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
})
}
+ fn consider_error_guaranteed_candidate(
+ ecx: &mut EvalCtxt<'_, 'tcx>,
+ _guar: ErrorGuaranteed,
+ ) -> QueryResult<'tcx> {
+ ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+ }
+
fn probe_and_match_goal_against_assumption(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
diff --git a/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs b/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
new file mode 100644
index 0000000000000..727ce84ba3591
--- /dev/null
+++ b/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
@@ -0,0 +1,25 @@
+// compile-flags: -Ztrait-solver=next
+
+// Checks that we do not get ambiguity by considering an impl
+// multiple times if we're able to normalize the self type.
+trait Trait<'a> {}
+
+impl<'a, T: 'a> Trait<'a> for T {}
+
+fn impls_trait<'a, T: Trait<'a>>() {}
+
+trait Id {
+ type Assoc;
+}
+impl<T> Id for T {
+ type Assoc = T;
+}
+
+fn call<T>() {
+ impls_trait::<<T as Id>::Assoc>();
+}
+
+fn main() {
+ call::<()>();
+ impls_trait::<<<() as Id>::Assoc as Id>::Assoc>();
+}
diff --git a/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr b/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr
new file mode 100644
index 0000000000000..91b635b35eb6c
--- /dev/null
+++ b/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr
@@ -0,0 +1,23 @@
+error[E0283]: type annotations needed: cannot satisfy `<T as Id>::Assoc: Trait<'_>`
+ --> $DIR/assemble-normalizing-self-ty-impl-ambiguity.rs:19:5
+ |
+LL | impls_trait::<<T as Id>::Assoc>();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: cannot satisfy `<T as Id>::Assoc: Trait<'_>`
+note: required by a bound in `impls_trait`
+ --> $DIR/assemble-normalizing-self-ty-impl-ambiguity.rs:9:23
+ |
+LL | fn impls_trait<'a, T: Trait<'a>>() {}
+ | ^^^^^^^^^ required by this bound in `impls_trait`
+
+error[E0282]: type annotations needed
+ --> $DIR/assemble-normalizing-self-ty-impl-ambiguity.rs:24:5
+ |
+LL | impls_trait::<<<() as Id>::Assoc as Id>::Assoc>();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `impls_trait`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0282, E0283.
+For more information about an error, try `rustc --explain E0282`.
From aa28b77b5a362a70e4c1e4f99047f903f735954d Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Tue, 18 Jul 2023 18:15:14 +0200
Subject: [PATCH 3/6] add FIXME
---
compiler/rustc_middle/src/ty/fast_reject.rs | 3 +++
1 file changed, 3 insertions(+)
diff --git a/compiler/rustc_middle/src/ty/fast_reject.rs b/compiler/rustc_middle/src/ty/fast_reject.rs
index deb4dcf1f760a..668aa4521c101 100644
--- a/compiler/rustc_middle/src/ty/fast_reject.rs
+++ b/compiler/rustc_middle/src/ty/fast_reject.rs
@@ -62,6 +62,9 @@ pub enum TreatParams {
/// correct mode for *lookup*, as during candidate selection.
///
/// N.B. during deep rejection, this acts identically to `ForLookup`.
+ ///
+ /// FIXME(-Ztrait-solver=next): Remove this variant and cleanup
+ /// the code.
NextSolverLookup,
}
From 7c97a76b76120bd982762a982d4254ece32c43dc Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Tue, 18 Jul 2023 18:18:32 +0200
Subject: [PATCH 4/6] re-add comment
---
compiler/rustc_trait_selection/src/solve/assembly/mod.rs | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index 73cf15ff94b59..68e931aac8c12 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -324,6 +324,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
candidates
}
+ /// HACK: `_: Trait` is ambiguous, because it may be satisfied via a builtin rule,
+ /// object bound, alias bound, etc. We are unable to determine this until we can at
+ /// least structurally resolve the type one layer.
+ ///
+ /// It would also require us to consider all impls of the trait, which is both pretty
+ /// bad for perf and would also constrain the self type if there is just a single impl.
fn self_ty_infer_ambiguity_hack<G: GoalKind<'tcx>>(
&mut self,
goal: Goal<'tcx, G>,
From 2062f2ca8261b521caa9c34c195bf472dcb59e98 Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Thu, 20 Jul 2023 10:40:59 +0200
Subject: [PATCH 5/6] review
---
.../src/solve/assembly/mod.rs | 8 +++----
...mble-normalizing-self-ty-impl-ambiguity.rs | 2 ++
...-normalizing-self-ty-impl-ambiguity.stderr | 23 -------------------
.../dont-normalize-proj-with-error.rs | 22 ++++++++++++++++++
.../dont-normalize-proj-with-error.stderr | 9 ++++++++
5 files changed, 37 insertions(+), 27 deletions(-)
delete mode 100644 tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr
create mode 100644 tests/ui/traits/new-solver/dont-normalize-proj-with-error.rs
create mode 100644 tests/ui/traits/new-solver/dont-normalize-proj-with-error.stderr
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index 68e931aac8c12..b661ff481a0a8 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -311,7 +311,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
goal: Goal<'tcx, G>,
) -> Vec<Candidate<'tcx>> {
debug_assert_eq!(goal, self.resolve_vars_if_possible(goal));
- if let Some(ambig) = self.self_ty_infer_ambiguity_hack(goal) {
+ if let Some(ambig) = self.assemble_self_ty_infer_ambiguity_response(goal) {
return ambig;
}
@@ -324,13 +324,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
candidates
}
- /// HACK: `_: Trait` is ambiguous, because it may be satisfied via a builtin rule,
+ /// `?0: Trait` is ambiguous, because it may be satisfied via a builtin rule,
/// object bound, alias bound, etc. We are unable to determine this until we can at
/// least structurally resolve the type one layer.
///
/// It would also require us to consider all impls of the trait, which is both pretty
/// bad for perf and would also constrain the self type if there is just a single impl.
- fn self_ty_infer_ambiguity_hack<G: GoalKind<'tcx>>(
+ fn assemble_self_ty_infer_ambiguity_response<G: GoalKind<'tcx>>(
&mut self,
goal: Goal<'tcx, G>,
) -> Option<Vec<Candidate<'tcx>>> {
@@ -353,7 +353,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
goal: Goal<'tcx, G>,
) -> Vec<Candidate<'tcx>> {
debug_assert_eq!(goal, self.resolve_vars_if_possible(goal));
- if let Some(ambig) = self.self_ty_infer_ambiguity_hack(goal) {
+ if let Some(ambig) = self.assemble_self_ty_infer_ambiguity_response(goal) {
return ambig;
}
diff --git a/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs b/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
index 727ce84ba3591..826e8c1e0b131 100644
--- a/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
+++ b/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
@@ -1,7 +1,9 @@
// compile-flags: -Ztrait-solver=next
+// check-pass
// Checks that we do not get ambiguity by considering an impl
// multiple times if we're able to normalize the self type.
+
trait Trait<'a> {}
impl<'a, T: 'a> Trait<'a> for T {}
diff --git a/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr b/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr
deleted file mode 100644
index 91b635b35eb6c..0000000000000
--- a/tests/ui/traits/new-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.stderr
+++ /dev/null
@@ -1,23 +0,0 @@
-error[E0283]: type annotations needed: cannot satisfy `<T as Id>::Assoc: Trait<'_>`
- --> $DIR/assemble-normalizing-self-ty-impl-ambiguity.rs:19:5
- |
-LL | impls_trait::<<T as Id>::Assoc>();
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- |
- = note: cannot satisfy `<T as Id>::Assoc: Trait<'_>`
-note: required by a bound in `impls_trait`
- --> $DIR/assemble-normalizing-self-ty-impl-ambiguity.rs:9:23
- |
-LL | fn impls_trait<'a, T: Trait<'a>>() {}
- | ^^^^^^^^^ required by this bound in `impls_trait`
-
-error[E0282]: type annotations needed
- --> $DIR/assemble-normalizing-self-ty-impl-ambiguity.rs:24:5
- |
-LL | impls_trait::<<<() as Id>::Assoc as Id>::Assoc>();
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `impls_trait`
-
-error: aborting due to 2 previous errors
-
-Some errors have detailed explanations: E0282, E0283.
-For more information about an error, try `rustc --explain E0282`.
diff --git a/tests/ui/traits/new-solver/dont-normalize-proj-with-error.rs b/tests/ui/traits/new-solver/dont-normalize-proj-with-error.rs
new file mode 100644
index 0000000000000..19a6fa990ff14
--- /dev/null
+++ b/tests/ui/traits/new-solver/dont-normalize-proj-with-error.rs
@@ -0,0 +1,22 @@
+// compile-flags: -Ztrait-solver=next
+
+// Test that we don't incorrectly leak unconstrained inference variables
+// if the projection contained an error. This caused an ICE in writeback.
+
+trait Mirror {
+ type Assoc: ?Sized;
+}
+
+struct Wrapper<T: ?Sized>(T);
+impl<T: ?Sized> Mirror for Wrapper<T> {
+ type Assoc = T;
+}
+
+fn mirror<W: Mirror>(_: W) -> Box<W::Assoc> { todo!() }
+
+fn type_error() -> TypeError { todo!() }
+//~^ ERROR cannot find type `TypeError` in this scope
+
+fn main() {
+ let x = mirror(type_error());
+}
diff --git a/tests/ui/traits/new-solver/dont-normalize-proj-with-error.stderr b/tests/ui/traits/new-solver/dont-normalize-proj-with-error.stderr
new file mode 100644
index 0000000000000..5a7459ec1fdee
--- /dev/null
+++ b/tests/ui/traits/new-solver/dont-normalize-proj-with-error.stderr
@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `TypeError` in this scope
+ --> $DIR/dont-normalize-proj-with-error.rs:17:20
+ |
+LL | fn type_error() -> TypeError { todo!() }
+ | ^^^^^^^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.
From 5c75bc5317b4326bdc3d8a4708d0602bd0ec219d Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Thu, 20 Jul 2023 11:26:22 +0200
Subject: [PATCH 6/6] update doc comments
---
.../src/solve/assembly/mod.rs | 27 ++++++++++++-------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index b661ff481a0a8..6920e790e71ae 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -184,18 +184,21 @@ pub(super) trait GoalKind<'tcx>:
impl_def_id: DefId,
) -> QueryResult<'tcx>;
- /// If the predicate contained an error, we want to avoid emitting unnecessary trait errors but
- /// still want to emit errors for other trait goals. We have some special handling for this case.
+ /// If the predicate contained an error, we want to avoid emitting unnecessary trait
+ /// errors but still want to emit errors for other trait goals. We have some special
+ /// handling for this case.
///
- /// Trait goals always hold while projection goals never do. This is a bit arbitrary but prevents
- /// incorrect normalization while hiding any trait errors.
+ /// Trait goals always hold while projection goals never do. This is a bit arbitrary
+ /// but prevents incorrect normalization while hiding any trait errors.
fn consider_error_guaranteed_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
guar: ErrorGuaranteed,
) -> QueryResult<'tcx>;
- /// A type implements an `auto trait` if its components do as well. These components
- /// are given by built-in rules from [`instantiate_constituent_tys_for_auto_trait`].
+ /// A type implements an `auto trait` if its components do as well.
+ ///
+ /// These components are given by built-in rules from
+ /// [`structural_traits::instantiate_constituent_tys_for_auto_trait`].
fn consider_auto_trait_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
@@ -207,15 +210,19 @@ pub(super) trait GoalKind<'tcx>:
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- /// A type is `Copy` or `Clone` if its components are `Sized`. These components
- /// are given by built-in rules from [`instantiate_constituent_tys_for_sized_trait`].
+ /// A type is `Copy` or `Clone` if its components are `Sized`.
+ ///
+ /// These components are given by built-in rules from
+ /// [`structural_traits::instantiate_constituent_tys_for_sized_trait`].
fn consider_builtin_sized_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
- /// A type is `Copy` or `Clone` if its components are `Copy` or `Clone`. These
- /// components are given by built-in rules from [`instantiate_constituent_tys_for_copy_clone_trait`].
+ /// A type is `Copy` or `Clone` if its components are `Copy` or `Clone`.
+ ///
+ /// These components are given by built-in rules from
+ /// [`structural_traits::instantiate_constituent_tys_for_copy_clone_trait`].
fn consider_builtin_copy_clone_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,