Merging upstream version 1.74.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 23 insertions, 81 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index 36194f973..23d2c0c4e 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -5,8 +5,10 @@ use crate::traits::coherence;
 use rustc_hir::def_id::DefId;
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::Reveal;
-use rustc_middle::traits::solve::inspect::CandidateKind;
-use rustc_middle::traits::solve::{CanonicalResponse, Certainty, Goal, QueryResult};
+use rustc_middle::traits::solve::inspect::ProbeKind;
+use rustc_middle::traits::solve::{
+    CandidateSource, CanonicalResponse, Certainty, Goal, QueryResult,
+};
 use rustc_middle::traits::BuiltinImplSource;
 use rustc_middle::ty::fast_reject::{SimplifiedType, TreatParams};
 use rustc_middle::ty::{self, Ty, TyCtxt};
@@ -27,66 +29,6 @@ pub(super) struct Candidate<'tcx> {
     pub(super) result: CanonicalResponse<'tcx>,
 }
 
-/// Possible ways the given goal can be proven.
-#[derive(Debug, Clone, Copy)]
-pub(super) enum CandidateSource {
-    /// A user written impl.
-    ///
-    /// ## Examples
-    ///
-    /// ```rust
-    /// fn main() {
-    ///     let x: Vec<u32> = Vec::new();
-    ///     // This uses the impl from the standard library to prove `Vec<T>: Clone`.
-    ///     let y = x.clone();
-    /// }
-    /// ```
-    Impl(DefId),
-    /// A builtin impl generated by the compiler. When adding a new special
-    /// trait, try to use actual impls whenever possible. Builtin impls should
-    /// only be used in cases where the impl cannot be manually be written.
-    ///
-    /// Notable examples are auto traits, `Sized`, and `DiscriminantKind`.
-    /// For a list of all traits with builtin impls, check out the
-    /// [`EvalCtxt::assemble_builtin_impl_candidates`] method. Not
-    BuiltinImpl(BuiltinImplSource),
-    /// An assumption from the environment.
-    ///
-    /// More precisely we've used the `n-th` assumption in the `param_env`.
-    ///
-    /// ## Examples
-    ///
-    /// ```rust
-    /// fn is_clone<T: Clone>(x: T) -> (T, T) {
-    ///     // This uses the assumption `T: Clone` from the `where`-bounds
-    ///     // to prove `T: Clone`.
-    ///     (x.clone(), x)
-    /// }
-    /// ```
-    ParamEnv(usize),
-    /// If the self type is an alias type, e.g. an opaque type or a projection,
-    /// we know the bounds on that alias to hold even without knowing its concrete
-    /// underlying type.
-    ///
-    /// More precisely this candidate is using the `n-th` bound in the `item_bounds` of
-    /// the self type.
-    ///
-    /// ## Examples
-    ///
-    /// ```rust
-    /// trait Trait {
-    ///     type Assoc: Clone;
-    /// }
-    ///
-    /// fn foo<T: Trait>(x: <T as Trait>::Assoc) {
-    ///     // We prove `<T as Trait>::Assoc` by looking at the bounds on `Assoc` in
-    ///     // in the trait definition.
-    ///     let _y = x.clone();
-    /// }
-    /// ```
-    AliasBound,
-}
-
 /// Methods used to assemble candidates for either trait or projection goals.
 pub(super) trait GoalKind<'tcx>:
     TypeFoldable<TyCtxt<'tcx>> + Copy + Eq + std::fmt::Display
@@ -399,7 +341,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         let tcx = self.tcx();
         let &ty::Alias(_, projection_ty) = goal.predicate.self_ty().kind() else { return };
 
-        candidates.extend(self.probe(|_| CandidateKind::NormalizedSelfTyAssembly).enter(|ecx| {
+        candidates.extend(self.probe(|_| ProbeKind::NormalizedSelfTyAssembly).enter(|ecx| {
             if num_steps < ecx.local_overflow_limit() {
                 let normalized_ty = ecx.next_ty_infer();
                 let normalizes_to_goal = goal.with(
@@ -527,7 +469,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             // FIXME: These should ideally not exist as a self type. It would be nice for
             // the builtin auto trait impls of generators to instead directly recurse
             // into the witness.
-            ty::GeneratorWitness(_) | ty::GeneratorWitnessMIR(_, _) => (),
+            ty::GeneratorWitness(..) => (),
 
             // These variants should not exist as a self type.
             ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_))
@@ -679,8 +621,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             | ty::Dynamic(..)
             | ty::Closure(..)
             | ty::Generator(..)
-            | ty::GeneratorWitness(_)
-            | ty::GeneratorWitnessMIR(..)
+            | ty::GeneratorWitness(..)
             | ty::Never
             | ty::Tuple(_)
             | ty::Param(_)
@@ -836,8 +777,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             | ty::Alias(..)
             | ty::Closure(..)
             | ty::Generator(..)
-            | ty::GeneratorWitness(_)
-            | ty::GeneratorWitnessMIR(..)
+            | ty::GeneratorWitness(..)
             | ty::Never
             | ty::Tuple(_)
             | ty::Param(_)
@@ -910,7 +850,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             SolverMode::Coherence => {}
         };
 
-        let result = self.probe_candidate("coherence unknowable").enter(|ecx| {
+        let result = self.probe_misc_candidate("coherence unknowable").enter(|ecx| {
             let trait_ref = goal.predicate.trait_ref(tcx);
 
             #[derive(Debug)]
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
index c47767101..16f288045 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
@@ -14,6 +14,7 @@ use crate::solve::EvalCtxt;
 //
 // For types with an "existential" binder, i.e. generator witnesses, we also
 // instantiate the binder with placeholders eagerly.
+#[instrument(level = "debug", skip(ecx), ret)]
 pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
     ty: Ty<'tcx>,
@@ -61,9 +62,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
             Ok(vec![generator_args.tupled_upvars_ty(), generator_args.witness()])
         }
 
-        ty::GeneratorWitness(types) => Ok(ecx.instantiate_binder_with_placeholders(types).to_vec()),
-
-        ty::GeneratorWitnessMIR(def_id, args) => Ok(ecx
+        ty::GeneratorWitness(def_id, args) => Ok(ecx
             .tcx()
             .generator_hidden_types(def_id)
             .map(|bty| {
@@ -96,8 +95,7 @@ pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>(
     let mut counter = 0;
     let ty = tcx.fold_regions(ty, |r, current_depth| match r.kind() {
         ty::ReErased => {
-            let br =
-                ty::BoundRegion { var: ty::BoundVar::from_u32(counter), kind: ty::BrAnon(None) };
+            let br = ty::BoundRegion { var: ty::BoundVar::from_u32(counter), kind: ty::BrAnon };
             counter += 1;
             ty::Region::new_late_bound(tcx, current_depth, br)
         }
@@ -105,11 +103,12 @@ pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>(
         r => bug!("unexpected region: {r:?}"),
     });
     let bound_vars = tcx.mk_bound_variable_kinds_from_iter(
-        (0..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon(None))),
+        (0..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon)),
     );
     ty::Binder::bind_with_vars(ty, bound_vars)
 }
 
+#[instrument(level = "debug", skip(ecx), ret)]
 pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
     ty: Ty<'tcx>,
@@ -127,7 +126,6 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
         | ty::Ref(..)
         | ty::Generator(..)
         | ty::GeneratorWitness(..)
-        | ty::GeneratorWitnessMIR(..)
         | ty::Array(..)
         | ty::Closure(..)
         | ty::Never
@@ -156,6 +154,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
     }
 }
 
+#[instrument(level = "debug", skip(ecx), ret)]
 pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
     ty: Ty<'tcx>,
@@ -204,9 +203,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
             }
         }
 
-        ty::GeneratorWitness(types) => Ok(ecx.instantiate_binder_with_placeholders(types).to_vec()),
-
-        ty::GeneratorWitnessMIR(def_id, args) => Ok(ecx
+        ty::GeneratorWitness(def_id, args) => Ok(ecx
             .tcx()
             .generator_hidden_types(def_id)
             .map(|bty| {
@@ -282,8 +279,7 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_callable<'tcx>(
         | ty::Ref(_, _, _)
         | ty::Dynamic(_, _, _)
         | ty::Generator(_, _, _)
-        | ty::GeneratorWitness(_)
-        | ty::GeneratorWitnessMIR(..)
+        | ty::GeneratorWitness(..)
         | ty::Never
         | ty::Tuple(_)
         | ty::Alias(_, _)
@@ -354,6 +350,12 @@ pub(in crate::solve) fn predicates_for_object_candidate<'tcx>(
         // FIXME(associated_const_equality): Also add associated consts to
         // the requirements here.
         if item.kind == ty::AssocKind::Type {
+            // associated types that require `Self: Sized` do not show up in the built-in
+            // implementation of `Trait for dyn Trait`, and can be dropped here.
+            if tcx.generics_require_sized_self(item.def_id) {
+                continue;
+            }
+
             requirements
                 .extend(tcx.item_bounds(item.def_id).iter_instantiated(tcx, trait_ref.args));
         }