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Simplify insert_outlives_predicate opaque type logic

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This commit is contained in:
Oli Scherer 2022-06-21 15:42:25 +00:00
parent 615c9e8647
commit 20d962cfa5
2 changed files with 23 additions and 31 deletions
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46
compiler/rustc_typeck/src/outlives/utils.rs
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@ -1,6 +1,6 @@
use rustc_infer::infer::outlives::components::{push_outlives_components, Component};
use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
use rustc_middle::ty::{self, EarlyBinder, Region, Ty, TyCtxt};
use rustc_middle::ty::{self, Region, Ty, TyCtxt};
use rustc_span::Span;
use smallvec::smallvec;
use std::collections::BTreeMap;
@ -97,36 +97,20 @@ pub(crate) fn insert_outlives_predicate<'tcx>(
}
Component::Opaque(def_id, substs) => {
for predicate in tcx.item_bounds(def_id) {
let predicate = EarlyBinder(predicate).subst(tcx, substs);
// FIXME(oli-obk): fishy skip-binder
match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(tp) => {
for subst in tp.trait_ref.substs {
insert_outlives_predicate(
tcx,
subst,
outlived_region,
span,
required_predicates,
)
}
}
ty::PredicateKind::RegionOutlives(_)
| ty::PredicateKind::TypeOutlives(_)
| ty::PredicateKind::Projection(_)
| ty::PredicateKind::WellFormed(_)
| ty::PredicateKind::ObjectSafe(_)
| ty::PredicateKind::ClosureKind(_, _, _)
| ty::PredicateKind::Subtype(_)
| ty::PredicateKind::Coerce(_)
| ty::PredicateKind::ConstEvaluatable(_)
| ty::PredicateKind::ConstEquate(_, _)
| ty::PredicateKind::TypeWellFormedFromEnv(_) => {
todo!("{:#?}", predicate)
}
}
}
// This would arise from something like:
//
// ```rust
// type Opaque<T> = impl Sized;
// fn defining<T>() -> Opaque<T> {}
// struct Ss<'a, T>(&'a Opaque<T>);
// ```
//
// Here we want to require an explicit `where Opaque<T>: 'a`
let ty = tcx.mk_opaque(def_id, substs);
required_predicates
.entry(ty::OutlivesPredicate(ty.into(), outlived_region))
.or_insert(span);
}
Component::EscapingProjection(_) => {

8
src/test/ui/type-alias-impl-trait/unbounded_opaque_type.rs Normal file
View File

@ -0,0 +1,8 @@
// check-pass
#![feature(type_alias_impl_trait)]
type Opaque<T> = impl Sized;
fn defining<T>() -> Opaque<T> {}
struct Ss<'a, T>(&'a Opaque<T>);
fn main() {}