1 files changed, 19 insertions, 0 deletions
diff --git a/src/test/ui/coherence/coherence-with-generator.rs b/src/test/ui/coherence/coherence-with-generator.rs
new file mode 100644
index 000000000..d34c391db
--- /dev/null
+++ b/src/test/ui/coherence/coherence-with-generator.rs
@@ -0,0 +1,19 @@
+// Test that encountering closures during coherence does not cause issues.
+#![feature(type_alias_impl_trait, generators)]
+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> {}
+//~^ ERROR cannot implement trait on type alias impl trait
+impl<T: Sync> Trait for Wrapper<T> {}
+//~^ ERROR conflicting implementations of trait `Trait` for type `Wrapper<OpaqueGenerator>`
+
+fn main() {}