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Don't structurally resolve in may_coerce

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This commit is contained in:
Michael Goulet 2024-10-15 13:26:56 -04:00
parent b4e9aad137
commit e3eba2d920
2 changed files with 16 additions and 14 deletions
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6
compiler/rustc_hir_typeck/src/coercion.rs
View file

@ -1091,16 +1091,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
/// ///
/// This should only be used for diagnostics. /// This should only be used for diagnostics.
pub(crate) fn may_coerce(&self, expr_ty: Ty<'tcx>, target_ty: Ty<'tcx>) -> bool { pub(crate) fn may_coerce(&self, expr_ty: Ty<'tcx>, target_ty: Ty<'tcx>) -> bool {
// FIXME(-Znext-solver): We need to structurally resolve both types here.
let source = self.resolve_vars_with_obligations(expr_ty);
debug!("coercion::can_with_predicates({:?} -> {:?})", source, target_ty);
let cause = self.cause(DUMMY_SP, ObligationCauseCode::ExprAssignable); let cause = self.cause(DUMMY_SP, ObligationCauseCode::ExprAssignable);
// We don't ever need two-phase here since we throw out the result of the coercion. // We don't ever need two-phase here since we throw out the result of the coercion.
// We also just always set `coerce_never` to true, since this is a heuristic. // We also just always set `coerce_never` to true, since this is a heuristic.
let coerce = Coerce::new(self, cause, AllowTwoPhase::No, true); let coerce = Coerce::new(self, cause, AllowTwoPhase::No, true);
self.probe(|_| { self.probe(|_| {
let Ok(ok) = coerce.coerce(source, target_ty) else { let Ok(ok) = coerce.coerce(expr_ty, target_ty) else {
return false; return false;
}; };
let ocx = ObligationCtxt::new(self); let ocx = ObligationCtxt::new(self);

24
tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.stderr
View file

@ -1,3 +1,15 @@
error[E0308]: mismatched types
--> $DIR/lazy_subtyping_of_opaques.rs:11:5
|
LL | fn reify_as_tait() -> Thunk<Tait> {
| ----------- expected `Thunk<_>` because of return type
LL |
LL | Thunk::new(|cont| cont)
| ^^^^^^^^^^^^^^^^^^^^^^^ expected `Thunk<_>`, found `()`
|
= note: expected struct `Thunk<_>`
found unit type `()`
error[E0277]: expected a `FnOnce()` closure, found `()` error[E0277]: expected a `FnOnce()` closure, found `()`
--> $DIR/lazy_subtyping_of_opaques.rs:11:23 --> $DIR/lazy_subtyping_of_opaques.rs:11:23
| |
@ -12,19 +24,13 @@ error[E0277]: expected a `FnOnce()` closure, found `()`
| |
LL | fn reify_as_tait() -> Thunk<Tait> { LL | fn reify_as_tait() -> Thunk<Tait> {
| ^^^^^^^^^^^ expected an `FnOnce()` closure, found `()` | ^^^^^^^^^^^ expected an `FnOnce()` closure, found `()`
LL |
LL | Thunk::new(|cont| cont)
| ----------------------- return type was inferred to be `{type error}` here
| |
= help: the trait `FnOnce()` is not implemented for `()` = help: the trait `FnOnce()` is not implemented for `()`
= note: wrap the `()` in a closure with no arguments: `|| { /* code */ }` = note: wrap the `()` in a closure with no arguments: `|| { /* code */ }`
error[E0308]: mismatched types
--> $DIR/lazy_subtyping_of_opaques.rs:11:5
|
LL | Thunk::new(|cont| cont)
| ^^^^^^^^^^^^^^^^^^^^^^^ expected `Thunk<_>`, found `()`
|
= note: expected struct `Thunk<_>`
found unit type `()`
error: aborting due to 3 previous errors error: aborting due to 3 previous errors
Some errors have detailed explanations: E0277, E0308. Some errors have detailed explanations: E0277, E0308.