nordic-dev.net/rust
nordic-dev.net/rust
2
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2024-11-26 00:34:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

Rollup merge of #121743 - compiler-errors:opportunistically-resolve-regions, r=jackh726

Browse Source 
Opportunistically resolve regions when processing region outlives obligations

Due to the matching in `TypeOutlives` being structural, we should attempt to opportunistically resolve regions before processing region obligations. Thanks ``@lcnr`` for finding this.

r? lcnr
This commit is contained in:
Matthias Krüger 2024-02-29 00:17:01 +01:00 committed by GitHub
commit 9f9daed889
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
3 changed files with 14 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
compiler/rustc_infer/src/infer/outlives/obligations.rs
View File

@ -62,6 +62,7 @@
use crate::infer::outlives::components::{push_outlives_components, Component};
use crate::infer::outlives::env::RegionBoundPairs;
use crate::infer::outlives::verify::VerifyBoundCx;
use crate::infer::resolve::OpportunisticRegionResolver;
use crate::infer::{
self, GenericKind, InferCtxt, RegionObligation, SubregionOrigin, UndoLog, VerifyBound,
};
@ -69,7 +70,9 @@ use crate::traits::{ObligationCause, ObligationCauseCode};
use rustc_data_structures::undo_log::UndoLogs;
use rustc_middle::mir::ConstraintCategory;
use rustc_middle::traits::query::NoSolution;
use rustc_middle::ty::{self, GenericArgsRef, Region, Ty, TyCtxt, TypeVisitableExt};
use rustc_middle::ty::{
self, GenericArgsRef, Region, Ty, TyCtxt, TypeFoldable as _, TypeVisitableExt,
};
use rustc_middle::ty::{GenericArgKind, PolyTypeOutlivesPredicate};
use rustc_span::DUMMY_SP;
use smallvec::smallvec;
@ -176,6 +179,11 @@ impl<'tcx> InferCtxt<'tcx> {
.map_err(|NoSolution| (outlives, origin.clone()))?
.no_bound_vars()
.expect("started with no bound vars, should end with no bound vars");
// `TypeOutlives` is structural, so we should try to opportunistically resolve all
// region vids before processing regions, so we have a better chance to match clauses
// in our param-env.
let (sup_type, sub_region) =
(sup_type, sub_region).fold_with(&mut OpportunisticRegionResolver::new(self));
debug!(?sup_type, ?sub_region, ?origin);

2
tests/ui/implied-bounds/impl-implied-bounds-compatibility.rs
View File

@ -10,7 +10,7 @@ pub trait MessageListenersInterface {
impl<'a> MessageListenersInterface for MessageListeners<'a> {
fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
//~^ ERROR cannot infer an appropriate lifetime for lifetime parameter 'b in generic type due to conflicting requirements
//~^ ERROR in type `&'a MessageListeners<'_>`, reference has a longer lifetime than the data it references
self
}
}

20
tests/ui/implied-bounds/impl-implied-bounds-compatibility.stderr
View File

@ -1,27 +1,15 @@
error[E0495]: cannot infer an appropriate lifetime for lifetime parameter 'b in generic type due to conflicting requirements
error[E0491]: in type `&'a MessageListeners<'_>`, reference has a longer lifetime than the data it references
--> $DIR/impl-implied-bounds-compatibility.rs:12:5
|
LL | fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: first, the lifetime cannot outlive the lifetime `'c` as defined here...
--> $DIR/impl-implied-bounds-compatibility.rs:12:5
|
LL | fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...so that the method type is compatible with trait
--> $DIR/impl-implied-bounds-compatibility.rs:12:5
|
LL | fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: expected `fn(&'c MessageListeners<'_>) -> &'c MessageListeners<'c>`
found `fn(&MessageListeners<'_>) -> &'a MessageListeners<'_>`
note: but, the lifetime must be valid for the lifetime `'a` as defined here...
note: the pointer is valid for the lifetime `'a` as defined here
--> $DIR/impl-implied-bounds-compatibility.rs:11:6
|
LL | impl<'a> MessageListenersInterface for MessageListeners<'a> {
| ^^
note: ...so that the reference type `&'a MessageListeners<'_>` does not outlive the data it points at
note: but the referenced data is only valid for the lifetime `'c` as defined here
--> $DIR/impl-implied-bounds-compatibility.rs:12:5
|
LL | fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
@ -29,4 +17,4 @@ LL | fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0495`.
For more information about this error, try `rustc --explain E0491`.