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Rollup merge of #67867 - matthewjasper:opaque-assoc-lookup, r=oli-obk

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Correctly check for opaque types in `assoc_ty_def`

Closes #67856
This commit is contained in:
Mazdak Farrokhzad 2020-01-12 03:27:56 +01:00 committed by GitHub
commit 1d9c69fb89
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3 changed files with 40 additions and 1 deletions
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2
src/librustc/traits/project.rs
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@ -1467,7 +1467,7 @@ fn assoc_ty_def(
// cycle error if the specialization graph is currently being built.
let impl_node = specialization_graph::Node::Impl(impl_def_id);
for item in impl_node.items(tcx) {
if item.kind == ty::AssocKind::Type
if matches!(item.kind, ty::AssocKind::Type | ty::AssocKind::OpaqueTy)
&& tcx.hygienic_eq(item.ident, assoc_ty_name, trait_def_id)
{
return specialization_graph::NodeItem {

16
src/test/ui/type-alias-impl-trait/incoherent-assoc-imp-trait.rs Normal file
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@ -0,0 +1,16 @@
// Regression test for issue 67856
#![feature(unboxed_closures)]
#![feature(type_alias_impl_trait)]
#![feature(fn_traits)]
trait MyTrait {}
impl MyTrait for () {}
impl<F> FnOnce<()> for &F {
//~^ ERROR conflicting implementations
//~| ERROR type parameter `F` must be used
type Output = impl MyTrait;
extern "rust-call" fn call_once(self, _: ()) -> Self::Output {}
}
fn main() {}

23
src/test/ui/type-alias-impl-trait/incoherent-assoc-imp-trait.stderr Normal file
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@ -0,0 +1,23 @@
error[E0119]: conflicting implementations of trait `std::ops::FnOnce<()>` for type `&_`:
--> $DIR/incoherent-assoc-imp-trait.rs:10:1
|
LL | impl<F> FnOnce<()> for &F {
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: conflicting implementation in crate `core`:
- impl<A, F> std::ops::FnOnce<A> for &F
where F: std::ops::Fn<A>, F: ?Sized;
error[E0210]: type parameter `F` must be used as the type parameter for some local type (e.g., `MyStruct<F>`)
--> $DIR/incoherent-assoc-imp-trait.rs:10:6
|
LL | impl<F> FnOnce<()> for &F {
| ^ type parameter `F` must be used as the type parameter for some local type
|
= note: implementing a foreign trait is only possible if at least one of the types for which is it implemented is local
= note: only traits defined in the current crate can be implemented for a type parameter
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0119, E0210.
For more information about an error, try `rustc --explain E0119`.