Auto merge of #79945 - jackh726:existential_trait_ref, r=nikomatsakis

Move binder for dyn to each list item

This essentially changes `ty::Binder<&'tcx List<ExistentialTraitRef>>` to `&'tcx List<ty::Binder<ExistentialTraitRef>>`.

This is a first step in moving the `dyn Trait` representation closer to Chalk, which we've talked about in `@rust-lang/wg-traits.`

r? `@nikomatsakis`
This commit is contained in:
bors 2020-12-17 18:21:20 +00:00
commit a921a476c8

View File

@ -480,17 +480,19 @@ impl<'tcx> CPlace<'tcx> {
// fn(&T) -> for<'l> fn(&'l T) is allowed
}
(&ty::Dynamic(from_traits, _), &ty::Dynamic(to_traits, _)) => {
let from_traits = fx
.tcx
.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from_traits);
let to_traits = fx
.tcx
.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to_traits);
assert_eq!(
from_traits, to_traits,
"Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
from_traits, to_traits, fx,
);
for (from, to) in from_traits.iter().zip(to_traits) {
let from = fx
.tcx
.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from);
let to = fx
.tcx
.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to);
assert_eq!(
from, to,
"Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
from_traits, to_traits, fx,
);
}
// dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
}
_ => {