diff options
7 files changed, 27 insertions, 32 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index 9a7d06ef640..b594723aa0b 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -2470,7 +2470,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { let projection_ty = ty::ProjectionTy { // `T` substs: self.tcx.mk_substs_trait( - trait_ref.self_ty().skip_binder(), + trait_pred.self_ty().skip_binder(), &self.fresh_substs_for_item(span, item_def_id)[1..], ), // `Future::Output` diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index 5e7d4c8b415..36cc14610cb 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -1073,6 +1073,16 @@ fn project<'cx, 'tcx>( return Ok(Projected::Progress(Progress::error(selcx.tcx()))); } + // If the obligation contains any inference types or consts in associated + // type substs, then we don't assemble any candidates. + // This isn't really correct, but otherwise we can end up in a case where + // we constrain inference variables by selecting a single predicate, when + // we need to stay general. See issue #91762. + let (_, predicate_own_substs) = obligation.predicate.trait_ref_and_own_substs(selcx.tcx()); + if predicate_own_substs.iter().any(|g| g.has_infer_types_or_consts()) { + return Err(ProjectionError::TooManyCandidates); + } + let mut candidates = ProjectionCandidateSet::None; // Make sure that the following procedures are kept in order. ParamEnv diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index 562535b0fea..47427395b93 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -1521,16 +1521,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { infer_predicate.projection_ty }; - // If the obligation contains any inference types or consts in associated - // type substs, then we don't match any projection candidates against it. - // This isn't really correct, but otherwise we can end up in a case where - // we constrain inference variables by selecting a single predicate, when - // we need to stay general. See issue #91762. - let (_, predicate_own_substs) = - obligation.predicate.trait_ref_and_own_substs(self.infcx.tcx); - if predicate_own_substs.iter().any(|g| g.has_infer_types_or_consts()) { - return false; - } self.infcx .at(&obligation.cause, obligation.param_env) .sup(obligation.predicate, infer_projection) diff --git a/src/test/ui/generic-associated-types/issue-74824.rs b/src/test/ui/generic-associated-types/issue-74824.rs index 1bbf7aac5cd..01f99fa4487 100644 --- a/src/test/ui/generic-associated-types/issue-74824.rs +++ b/src/test/ui/generic-associated-types/issue-74824.rs @@ -17,6 +17,7 @@ impl<T> UnsafeCopy for T {} fn main() { let b = Box::new(42usize); let copy = <()>::copy(&b); + //~^ type annotations needed let raw_b = Box::deref(&b) as *const _; let raw_copy = Box::deref(©) as *const _; diff --git a/src/test/ui/generic-associated-types/issue-74824.stderr b/src/test/ui/generic-associated-types/issue-74824.stderr index 8517eb9fa21..e7ebf5964ba 100644 --- a/src/test/ui/generic-associated-types/issue-74824.stderr +++ b/src/test/ui/generic-associated-types/issue-74824.stderr @@ -27,6 +27,13 @@ help: consider restricting type parameter `T` LL | type Copy<T: std::clone::Clone>: Copy = Box<T>; | +++++++++++++++++++ -error: aborting due to 2 previous errors +error[E0282]: type annotations needed + --> $DIR/issue-74824.rs:19:16 + | +LL | let copy = <()>::copy(&b); + | ^^^^^^^^^^ cannot infer type for type parameter `T` declared on the associated function `copy` + +error: aborting due to 3 previous errors -For more information about this error, try `rustc --explain E0277`. +Some errors have detailed explanations: E0277, E0282. +For more information about an error, try `rustc --explain E0277`. diff --git a/src/test/ui/generic-associated-types/issue-91762.rs b/src/test/ui/generic-associated-types/issue-91762.rs index e39a127abfd..b259a3c6e06 100644 --- a/src/test/ui/generic-associated-types/issue-91762.rs +++ b/src/test/ui/generic-associated-types/issue-91762.rs @@ -23,7 +23,7 @@ pub trait FunctorExt<T>: Sized { arg = self; ret = <Self::Base as Functor>::fmap(arg); - //~^ mismatched types + //~^ type annotations needed } } diff --git a/src/test/ui/generic-associated-types/issue-91762.stderr b/src/test/ui/generic-associated-types/issue-91762.stderr index e177e151d8a..a9c465cdd7e 100644 --- a/src/test/ui/generic-associated-types/issue-91762.stderr +++ b/src/test/ui/generic-associated-types/issue-91762.stderr @@ -1,22 +1,9 @@ -error[E0308]: mismatched types - --> $DIR/issue-91762.rs:25:45 +error[E0282]: type annotations needed + --> $DIR/issue-91762.rs:25:15 | -LL | / pub trait FunctorExt<T>: Sized { -LL | | type Base: Functor<With<T> = Self>; -LL | | -LL | | fn fmap<U>(self) { -... | -LL | | ret = <Self::Base as Functor>::fmap(arg); - | | ^^^ expected associated type, found type parameter `Self` -LL | | -LL | | } -LL | | } - | |_- this type parameter - | - = note: expected associated type `<<Self as FunctorExt<T>>::Base as Functor>::With<_>` - found type parameter `Self` - = note: you might be missing a type parameter or trait bound +LL | ret = <Self::Base as Functor>::fmap(arg); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the associated function `fmap` error: aborting due to previous error -For more information about this error, try `rustc --explain E0308`. +For more information about this error, try `rustc --explain E0282`. |