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Auto merge of #90948 - oli-obk:🧹, r=nikomatsakis

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Actually instantiate the opaque type when checking bounds

Before this change, `instantiate_opaque_types` was a no-op, because it only works relative to the defined opaque type inference anchor. If it is a no-op, the for loop will not actually have anything to iterate over, and thus nothing is checked at all.
This commit is contained in:
bors 2022-01-11 17:31:07 +00:00
commit 1409c015b4
2 changed files with 49 additions and 21 deletions
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44
compiler/rustc_typeck/src/check/check.rs
View File

@ -626,6 +626,7 @@ pub(super) fn check_opaque_for_cycles<'tcx>(
///
/// Without this check the above code is incorrectly accepted: we would ICE if
/// some tried, for example, to clone an `Option<X<&mut ()>>`.
#[instrument(level = "debug", skip(tcx))]
fn check_opaque_meets_bounds<'tcx>(
tcx: TyCtxt<'tcx>,
def_id: LocalDefId,
@ -633,17 +634,14 @@ fn check_opaque_meets_bounds<'tcx>(
span: Span,
origin: &hir::OpaqueTyOrigin,
) {
match origin {
// Checked when type checking the function containing them.
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => return,
// Can have different predicates to their defining use
hir::OpaqueTyOrigin::TyAlias => {}
}
let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
let param_env = tcx.param_env(def_id);
let defining_use_anchor = match *origin {
hir::OpaqueTyOrigin::FnReturn(did) | hir::OpaqueTyOrigin::AsyncFn(did) => did,
hir::OpaqueTyOrigin::TyAlias => def_id,
};
let param_env = tcx.param_env(defining_use_anchor);
tcx.infer_ctxt().enter(move |infcx| {
tcx.infer_ctxt().with_opaque_type_inference(defining_use_anchor).enter(move |infcx| {
let inh = Inherited::new(infcx, def_id);
let infcx = &inh.infcx;
let opaque_ty = tcx.mk_opaque(def_id.to_def_id(), substs);
@ -656,16 +654,15 @@ fn check_opaque_meets_bounds<'tcx>(
let opaque_type_map = infcx.inner.borrow().opaque_types.clone();
for (OpaqueTypeKey { def_id, substs }, opaque_defn) in opaque_type_map {
match infcx
.at(&misc_cause, param_env)
.eq(opaque_defn.concrete_ty, tcx.type_of(def_id).subst(tcx, substs))
{
let hidden_type = tcx.type_of(def_id).subst(tcx, substs);
trace!(?hidden_type);
match infcx.at(&misc_cause, param_env).eq(opaque_defn.concrete_ty, hidden_type) {
Ok(infer_ok) => inh.register_infer_ok_obligations(infer_ok),
Err(ty_err) => tcx.sess.delay_span_bug(
opaque_defn.definition_span,
span,
&format!(
"could not unify `{}` with revealed type:\n{}",
opaque_defn.concrete_ty, ty_err,
"could not check bounds on revealed type `{}`:\n{}",
hidden_type, ty_err,
),
),
}
@ -678,10 +675,17 @@ fn check_opaque_meets_bounds<'tcx>(
infcx.report_fulfillment_errors(&errors, None, false);
}
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
let fcx = FnCtxt::new(&inh, param_env, hir_id);
fcx.regionck_item(hir_id, span, FxHashSet::default());
match origin {
// Checked when type checking the function containing them.
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => return,
// Can have different predicates to their defining use
hir::OpaqueTyOrigin::TyAlias => {
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
let fcx = FnCtxt::new(&inh, param_env, hir_id);
fcx.regionck_item(hir_id, span, FxHashSet::default());
}
}
});
}

26
src/test/ui/type-alias-impl-trait/issue-57611-trait-alias.nll.stderr
View File

@ -10,5 +10,29 @@ error: higher-ranked subtype error
LL | |x| x
| ^^^^^
error: aborting due to 2 previous errors
error[E0308]: mismatched types
--> $DIR/issue-57611-trait-alias.rs:17:16
|
LL | type Bar = impl Baz<Self, Self>;
| ^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
|
= note: expected type `for<'r> Fn<(&'r X,)>`
found type `Fn<(&'static X,)>`
note: this closure does not fulfill the lifetime requirements
--> $DIR/issue-57611-trait-alias.rs:21:9
|
LL | |x| x
| ^^^^^
error: implementation of `FnOnce` is not general enough
--> $DIR/issue-57611-trait-alias.rs:17:16
|
LL | type Bar = impl Baz<Self, Self>;
| ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
|
= note: closure with signature `fn(&'static X) -> &'static X` must implement `FnOnce<(&'0 X,)>`, for any lifetime `'0`...
= note: ...but it actually implements `FnOnce<(&'static X,)>`
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0308`.