Add definable opaque types to the selection cache key

Author: oli-obk

compiler/rustc_middle/src/traits/select.rs

@@ -9,15 +9,15 @@ use rustc_errors::ErrorGuaranteed;
 
 use crate::ty;
 
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_macros::{HashStable, TypeVisitable};
 use rustc_query_system::cache::Cache;
 
 pub type SelectionCache<'tcx> = Cache<
     // This cache does not use `ParamEnvAnd` in its keys because `ParamEnv::and` can replace
     // caller bounds with an empty list if the `TraitPredicate` looks global, which may happen
     // after erasing lifetimes from the predicate.
-    (ty::ParamEnv<'tcx>, ty::TraitPredicate<'tcx>),
+    (&'tcx ty::List<LocalDefId>, ty::ParamEnv<'tcx>, ty::TraitPredicate<'tcx>),
     SelectionResult<'tcx, SelectionCandidate<'tcx>>,
 >;
 

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -49,6 +49,7 @@ use rustc_middle::ty::{self, PolyProjectionPredicate, Upcast};
 use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
 use rustc_span::symbol::sym;
 use rustc_span::Symbol;
+use rustc_type_ir::InferCtxtLike as _;
 
 use std::cell::{Cell, RefCell};
 use std::cmp;
@@ -1559,13 +1560,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         }
         let tcx = self.tcx();
         let pred = cache_fresh_trait_pred.skip_binder();
+        let opaques = self.infcx.defining_opaque_types();
 
         if self.can_use_global_caches(param_env) {
-            if let Some(res) = tcx.selection_cache.get(&(param_env, pred), tcx) {
+            if let Some(res) = tcx.selection_cache.get(&(opaques, param_env, pred), tcx) {
                 return Some(res);
             }
         }
-        self.infcx.selection_cache.get(&(param_env, pred), tcx)
+        self.infcx.selection_cache.get(&(opaques, param_env, pred), tcx)
     }
 
     /// Determines whether can we safely cache the result
@@ -1611,6 +1613,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     ) {
         let tcx = self.tcx();
         let pred = cache_fresh_trait_pred.skip_binder();
+        let opaques = self.infcx.defining_opaque_types();
 
         if !self.can_cache_candidate(&candidate) {
             debug!(?pred, ?candidate, "insert_candidate_cache - candidate is not cacheable");
@@ -1624,14 +1627,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 if !candidate.has_infer() {
                     debug!(?pred, ?candidate, "insert_candidate_cache global");
                     // This may overwrite the cache with the same value.
-                    tcx.selection_cache.insert((param_env, pred), dep_node, candidate);
+                    tcx.selection_cache.insert((opaques, param_env, pred), dep_node, candidate);
                     return;
                 }
             }
         }
 
         debug!(?pred, ?candidate, "insert_candidate_cache local");
-        self.infcx.selection_cache.insert((param_env, pred), dep_node, candidate);
+        self.infcx.selection_cache.insert((opaques, param_env, pred), dep_node, candidate);
     }
 
     /// Looks at the item bounds of the projection or opaque type.

tests/crashes/119272.rs renamed to tests/ui/auto-traits/opaque_type_candidate_selection.rs

@@ -1,10 +1,11 @@
-//@ known-bug: #119272
+//! used to ICE: #119272
 #![feature(type_alias_impl_trait)]
 mod defining_scope {
     use super::*;
     pub type Alias<T> = impl Sized;
 
     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
+        //~^ ERROR: type annotations needed
         x
     }
 }

tests/ui/auto-traits/opaque_type_candidate_selection.stderr

@@ -0,0 +1,21 @@
+error[E0284]: type annotations needed
+  --> $DIR/opaque_type_candidate_selection.rs:7:20
+   |
+LL |     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
+   |                    ^ cannot infer type
+   |
+   = note: cannot satisfy `<Alias<T> as Trait<T>>::Assoc == _`
+note: required because it appears within the type `Container<Alias<T>, T>`
+  --> $DIR/opaque_type_candidate_selection.rs:13:8
+   |
+LL | struct Container<T: Trait<U>, U> {
+   |        ^^^^^^^^^
+   = help: unsized fn params are gated as an unstable feature
+help: function arguments must have a statically known size, borrowed types always have a known size
+   |
+LL |     pub fn cast<T>(x: &Container<Alias<T>, T>) -> Container<T, T> {
+   |                       +
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0284`.

tests/ui/coherence/occurs-check/opaques.next.stderr

@@ -1,5 +1,5 @@
 error[E0119]: conflicting implementations of trait `Trait<_>`
-  --> $DIR/opaques.rs:30:1
+  --> $DIR/opaques.rs:28:1
    |
 LL | impl<T> Trait<T> for T {
    | ---------------------- first implementation here
@@ -8,7 +8,7 @@ LL | impl<T> Trait<T> for defining_scope::Alias<T> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation
 
 error[E0282]: type annotations needed
-  --> $DIR/opaques.rs:13:20
+  --> $DIR/opaques.rs:11:20
    |
 LL |     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
    |                    ^ cannot infer type

tests/ui/coherence/occurs-check/opaques.old.stderr

@@ -0,0 +1,21 @@
+error[E0284]: type annotations needed
+  --> $DIR/opaques.rs:11:20
+   |
+LL |     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
+   |                    ^ cannot infer type
+   |
+   = note: cannot satisfy `<Alias<T> as Trait<T>>::Assoc == _`
+note: required because it appears within the type `Container<Alias<T>, T>`
+  --> $DIR/opaques.rs:17:8
+   |
+LL | struct Container<T: Trait<U>, U> {
+   |        ^^^^^^^^^
+   = help: unsized fn params are gated as an unstable feature
+help: function arguments must have a statically known size, borrowed types always have a known size
+   |
+LL |     pub fn cast<T>(x: &Container<Alias<T>, T>) -> Container<T, T> {
+   |                       +
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0284`.

tests/ui/coherence/occurs-check/opaques.rs

@@ -3,15 +3,13 @@
 
 // A regression test for #105787
 
-//@[old] known-bug: #105787
-//@[old] check-pass
 #![feature(type_alias_impl_trait)]
 mod defining_scope {
     use super::*;
     pub type Alias<T> = impl Sized;
 
     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
-        //[next]~^ ERROR type annotations needed
+        //~^ ERROR type annotations needed
         x
     }
 }