diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs index 416865e861ea..d4e6a23f0eb6 100644 --- a/compiler/rustc_trait_selection/src/traits/wf.rs +++ b/compiler/rustc_trait_selection/src/traits/wf.rs @@ -567,6 +567,14 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> { def_id: DefId, args: GenericArgsRef<'tcx>, ) -> PredicateObligations<'tcx> { + // PERF: `Sized`'s predicates include `MetaSized`, but both are compiler implemented marker + // traits, so `MetaSized` will always be WF if `Sized` is WF and vice-versa. Determining + // the nominal obligations of `Sized` would in-effect just elaborate `MetaSized` and make + // the compiler do a bunch of work needlessly. + if self.tcx().is_lang_item(def_id, LangItem::Sized) { + return Default::default(); + } + let predicates = self.tcx().predicates_of(def_id); let mut origins = vec![def_id; predicates.predicates.len()]; let mut head = predicates; diff --git a/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.current.stderr b/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.current.stderr index dd9393fae853..d99a4cbd3780 100644 --- a/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.current.stderr +++ b/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.current.stderr @@ -1,20 +1,5 @@ -error[E0308]: mismatched types - --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:13:23 - | -LL | (MyType<'a, T>,): Sized, - | ^^^^^ lifetime mismatch - | - = note: expected trait ` as Sized>` - found trait ` as Sized>` -note: the lifetime `'a` as defined here... - --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:11:8 - | -LL | fn foo<'a, T: ?Sized>() - | ^^ - = note: ...does not necessarily outlive the static lifetime - error: lifetime may not live long enough - --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:22:5 + --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:20:5 | LL | fn foo<'a, T: ?Sized>() | -- lifetime `'a` defined here @@ -22,6 +7,5 @@ LL | fn foo<'a, T: ?Sized>() LL | is_sized::<(MyType<'a, T>,)>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static` -error: aborting due to 2 previous errors +error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0308`. diff --git a/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.next.stderr b/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.next.stderr index 05861877d413..d99a4cbd3780 100644 --- a/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.next.stderr +++ b/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.next.stderr @@ -1,18 +1,5 @@ -error[E0478]: lifetime bound not satisfied - --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:13:23 - | -LL | (MyType<'a, T>,): Sized, - | ^^^^^ - | -note: lifetime parameter instantiated with the lifetime `'a` as defined here - --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:11:8 - | -LL | fn foo<'a, T: ?Sized>() - | ^^ - = note: but lifetime parameter must outlive the static lifetime - error: lifetime may not live long enough - --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:22:5 + --> $DIR/lifetime-incomplete-prefer-sized-builtin-over-wc.rs:20:5 | LL | fn foo<'a, T: ?Sized>() | -- lifetime `'a` defined here @@ -20,6 +7,5 @@ LL | fn foo<'a, T: ?Sized>() LL | is_sized::<(MyType<'a, T>,)>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static` -error: aborting due to 2 previous errors +error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0478`. diff --git a/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.rs b/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.rs index ae7a6c9bba33..6ddc0628dd19 100644 --- a/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.rs +++ b/tests/ui/traits/lifetime-incomplete-prefer-sized-builtin-over-wc.rs @@ -11,8 +11,6 @@ fn is_sized() {} fn foo<'a, T: ?Sized>() where (MyType<'a, T>,): Sized, - //[current]~^ ERROR mismatched types - //[next]~^^ ERROR lifetime bound not satisfied MyType<'static, T>: Sized, { // Preferring the builtin `Sized` impl of tuples