1 files changed, 29 insertions, 0 deletions
diff --git a/src/test/ui/rust-2018/uniform-paths/issue-55779.rs b/src/test/ui/rust-2018/uniform-paths/issue-55779.rs
new file mode 100644
index 000000000..0af17a89b
--- /dev/null
+++ b/src/test/ui/rust-2018/uniform-paths/issue-55779.rs
@@ -0,0 +1,29 @@
+// run-pass
+// edition:2018
+// aux-crate:issue_55779_extern_trait=issue-55779-extern-trait.rs
+
+use issue_55779_extern_trait::Trait;
+
+struct Local;
+struct Helper;
+
+impl Trait for Local {
+    fn no_op(&self)
+    {
+        // (Unused) extern crate declaration necessary to reproduce bug
+        extern crate issue_55779_extern_trait;
+
+        // This one works
+        // impl Trait for Helper { fn no_op(&self) { } }
+
+        // This one infinite-loops
+        const _IMPL_SERIALIZE_FOR_HELPER: () = {
+            // (extern crate can also appear here to reproduce bug,
+            // as in originating example from serde)
+            impl Trait for Helper { fn no_op(&self) { } }
+        };
+
+    }
+}
+
+fn main() { }