1 files changed, 24 insertions, 0 deletions
diff --git a/tests/ui/coherence/coherence-with-generator.rs b/tests/ui/coherence/coherence-with-generator.rs
new file mode 100644
index 000000000..5eb8dc2a4
--- /dev/null
+++ b/tests/ui/coherence/coherence-with-generator.rs
@@ -0,0 +1,24 @@
+// Test that encountering closures during coherence does not cause issues.
+#![feature(type_alias_impl_trait, generators)]
+#![cfg_attr(specialized, feature(specialization))]
+#![allow(incomplete_features)]
+
+// revisions: stock specialized
+// [specialized]check-pass
+
+type OpaqueGenerator = impl Sized;
+fn defining_use() -> OpaqueGenerator {
+    || {
+        for i in 0..10 {
+            yield i;
+        }
+    }
+}
+
+struct Wrapper<T>(T);
+trait Trait {}
+impl Trait for Wrapper<OpaqueGenerator> {}
+impl<T: Sync> Trait for Wrapper<T> {}
+//[stock]~^ ERROR conflicting implementations of trait `Trait` for type `Wrapper<OpaqueGenerator>`
+
+fn main() {}