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Don't require lifetime super-bounds on traits apply to trait objects of that trait

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This commit is contained in:
Matthew Jasper 2020-08-15 12:29:23 +01:00
parent e674cf0200
commit e42c97919c
2 changed files with 33 additions and 14 deletions
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31
compiler/rustc_trait_selection/src/traits/select/confirmation.rs
View file

@ -439,26 +439,29 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let upcast_trait_ref = upcast_trait_ref.unwrap();
// Check supertraits hold
// Check supertraits hold. This is so that their associated type bounds
// will be checked in the code below.
for super_trait in tcx
.super_predicates_of(trait_predicate.def_id())
.instantiate(tcx, trait_predicate.trait_ref.substs)
.predicates
.into_iter()
{
let normalized_super_trait = normalize_with_depth_to(
self,
obligation.param_env,
obligation.cause.clone(),
obligation.recursion_depth + 1,
&super_trait,
&mut nested,
);
nested.push(Obligation::new(
obligation.cause.clone(),
obligation.param_env.clone(),
normalized_super_trait,
));
if let ty::PredicateAtom::Trait(..) = super_trait.skip_binders() {
let normalized_super_trait = normalize_with_depth_to(
self,
obligation.param_env,
obligation.cause.clone(),
obligation.recursion_depth + 1,
&super_trait,
&mut nested,
);
nested.push(Obligation::new(
obligation.cause.clone(),
obligation.param_env.clone(),
normalized_super_trait,
));
}
}
let assoc_types: Vec<_> = tcx

16
src/test/ui/traits/trait-object-supertrait-lifetime-bound.rs Normal file
View file

@ -0,0 +1,16 @@
// check-pass
use std::any::Any;
trait A<T>: Any {
fn m(&self) {}
}
impl<S, T: 'static> A<S> for T {}
fn call_obj<'a>() {
let obj: &dyn A<&'a ()> = &();
obj.m();
}
fn main() {}