bjoernager/rust
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Point at explicit 'static obligations on a trait

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Given `trait Any: 'static` and a `struct` with a `Box<dyn Any + 'a>` field, point at the `'static` bound in `Any` to explain why `'a: 'static`.

```
error[E0478]: lifetime bound not satisfied
   --> f202.rs:2:12
    |
2   |     value: Box<dyn std::any::Any + 'a>,
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: lifetime parameter instantiated with the lifetime `'a` as defined here
   --> f202.rs:1:14
    |
1   | struct Hello<'a> {
    |              ^^
note: but lifetime parameter must outlive the static lifetime
   --> /home/gh-estebank/rust/library/core/src/any.rs:113:16
    |
113 | pub trait Any: 'static {
    |                ^^^^^^^
```

Partially address #33652.
This commit is contained in:
Esteban Küber 2024-08-12 22:57:14 +00:00
parent 4d5b3b1962
commit f5bae722be
8 changed files with 80 additions and 11 deletions
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2
compiler/rustc_infer/src/infer/context.rs
View file

@ -167,7 +167,7 @@ impl<'tcx> InferCtxtLike for InferCtxt<'tcx> {
}
fn sub_regions(&self, sub: ty::Region<'tcx>, sup: ty::Region<'tcx>) {
self.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP), sub, sup)
self.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP, None), sub, sup)
}
fn register_ty_outlives(&self, ty: Ty<'tcx>, r: ty::Region<'tcx>) {

10
compiler/rustc_infer/src/infer/mod.rs
View file

@ -390,7 +390,7 @@ pub enum SubregionOrigin<'tcx> {
/// The given region parameter was instantiated with a region
/// that must outlive some other region.
RelateRegionParamBound(Span),
RelateRegionParamBound(Span, Option<Ty<'tcx>>),
/// Creating a pointer `b` to contents of another reference.
Reborrow(Span),
@ -859,7 +859,7 @@ impl<'tcx> InferCtxt<'tcx> {
) {
self.enter_forall(predicate, |ty::OutlivesPredicate(r_a, r_b)| {
let origin = SubregionOrigin::from_obligation_cause(cause, || {
RelateRegionParamBound(cause.span)
RelateRegionParamBound(cause.span, None)
});
self.sub_regions(origin, r_b, r_a); // `b : a` ==> `a <= b`
})
@ -1685,7 +1685,7 @@ impl<'tcx> SubregionOrigin<'tcx> {
Subtype(ref a) => a.span(),
RelateObjectBound(a) => a,
RelateParamBound(a, ..) => a,
RelateRegionParamBound(a) => a,
RelateRegionParamBound(a, _) => a,
Reborrow(a) => a,
ReferenceOutlivesReferent(_, a) => a,
CompareImplItemObligation { span, .. } => span,
@ -1726,6 +1726,10 @@ impl<'tcx> SubregionOrigin<'tcx> {
SubregionOrigin::AscribeUserTypeProvePredicate(span)
}
traits::ObligationCauseCode::ObjectTypeBound(ty, _reg) => {
SubregionOrigin::RelateRegionParamBound(cause.span, Some(ty))
}
_ => default(),
}
}