diff options
| -rw-r--r-- | compiler/rustc_infer/src/infer/opaque_types.rs | 14 | ||||
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/project.rs | 21 | ||||
| -rw-r--r-- | src/test/ui/impl-trait/nested-return-type2.rs | 8 | ||||
| -rw-r--r-- | src/test/ui/impl-trait/nested-return-type2.stderr | 16 |
4 files changed, 28 insertions, 31 deletions
diff --git a/compiler/rustc_infer/src/infer/opaque_types.rs b/compiler/rustc_infer/src/infer/opaque_types.rs index 7684d861f3c..ebb8d443421 100644 --- a/compiler/rustc_infer/src/infer/opaque_types.rs +++ b/compiler/rustc_infer/src/infer/opaque_types.rs @@ -39,21 +39,19 @@ pub struct OpaqueTypeDecl<'tcx> { } impl<'a, 'tcx> InferCtxt<'a, 'tcx> { - /// This is a backwards compatibility hack to prevent breaking changes from - /// lazy TAIT around RPIT handling. - pub fn replace_opaque_types_with_inference_vars<T: TypeFoldable<'tcx>>( + pub fn replace_opaque_types_with_inference_vars( &self, - value: T, + ty: Ty<'tcx>, body_id: HirId, span: Span, code: ObligationCauseCode<'tcx>, param_env: ty::ParamEnv<'tcx>, - ) -> InferOk<'tcx, T> { - if !value.has_opaque_types() { - return InferOk { value, obligations: vec![] }; + ) -> InferOk<'tcx, Ty<'tcx>> { + if !ty.has_opaque_types() { + return InferOk { value: ty, obligations: vec![] }; } let mut obligations = vec![]; - let value = value.fold_with(&mut ty::fold::BottomUpFolder { + let value = ty.fold_with(&mut ty::fold::BottomUpFolder { tcx: self.tcx, lt_op: |lt| lt, ct_op: |ct| ct, diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index 82c54291a5d..aba4f144d4b 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -28,7 +28,6 @@ use rustc_hir::def::DefKind; use rustc_hir::def_id::DefId; use rustc_hir::lang_items::LangItem; use rustc_infer::infer::resolve::OpportunisticRegionResolver; -use rustc_infer::traits::ObligationCauseCode; use rustc_middle::traits::select::OverflowError; use rustc_middle::ty::fold::{MaxUniverse, TypeFoldable, TypeFolder, TypeSuperFoldable}; use rustc_middle::ty::subst::Subst; @@ -252,22 +251,10 @@ fn project_and_unify_type<'cx, 'tcx>( Err(InProgress) => return ProjectAndUnifyResult::Recursive, }; debug!(?normalized, ?obligations, "project_and_unify_type result"); - let actual = obligation.predicate.term; - // HACK: lazy TAIT would regress src/test/ui/impl-trait/nested-return-type2.rs, so we add - // a back-compat hack hat converts the RPITs into inference vars, just like they were before - // lazy TAIT. - // This does not affect TAITs in general, as tested in the nested-return-type-tait* tests. - let InferOk { value: actual, obligations: new } = - selcx.infcx().replace_opaque_types_with_inference_vars( - actual, - obligation.cause.body_id, - obligation.cause.span, - ObligationCauseCode::MiscObligation, - obligation.param_env, - ); - obligations.extend(new); - - match infcx.at(&obligation.cause, obligation.param_env).eq(normalized, actual) { + match infcx + .at(&obligation.cause, obligation.param_env) + .eq(normalized, obligation.predicate.term) + { Ok(InferOk { obligations: inferred_obligations, value: () }) => { obligations.extend(inferred_obligations); ProjectAndUnifyResult::Holds(obligations) diff --git a/src/test/ui/impl-trait/nested-return-type2.rs b/src/test/ui/impl-trait/nested-return-type2.rs index 39928d543e1..279641a46c3 100644 --- a/src/test/ui/impl-trait/nested-return-type2.rs +++ b/src/test/ui/impl-trait/nested-return-type2.rs @@ -1,5 +1,3 @@ -// check-pass - trait Duh {} impl Duh for i32 {} @@ -20,11 +18,9 @@ impl<R: Duh, F: FnMut() -> R> Trait for F { // the hidden type. We already have obligations registered on the inference // var to make it uphold the `: Duh` bound on `Trait::Assoc`. The opaque // type does not implement `Duh`, even if its hidden type does. -// Lazy TAIT would error out, but we inserted a hack to make it work again, -// keeping backwards compatibility. fn foo() -> impl Trait<Assoc = impl Send> { + //~^ ERROR `impl Send: Duh` is not satisfied || 42 } -fn main() { -} +fn main() {} diff --git a/src/test/ui/impl-trait/nested-return-type2.stderr b/src/test/ui/impl-trait/nested-return-type2.stderr new file mode 100644 index 00000000000..f996e99de07 --- /dev/null +++ b/src/test/ui/impl-trait/nested-return-type2.stderr @@ -0,0 +1,16 @@ +error[E0277]: the trait bound `impl Send: Duh` is not satisfied + --> $DIR/nested-return-type2.rs:21:13 + | +LL | fn foo() -> impl Trait<Assoc = impl Send> { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Duh` is not implemented for `impl Send` + | + = help: the trait `Duh` is implemented for `i32` +note: required because of the requirements on the impl of `Trait` for `[closure@$DIR/nested-return-type2.rs:23:5: 23:10]` + --> $DIR/nested-return-type2.rs:12:31 + | +LL | impl<R: Duh, F: FnMut() -> R> Trait for F { + | ^^^^^ ^ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0277`. |