1 files changed, 24 insertions, 0 deletions
diff --git a/src/test/ui/nll/relate_tys/hr-fn-aaa-as-aba.rs b/src/test/ui/nll/relate_tys/hr-fn-aaa-as-aba.rs
new file mode 100644
index 000000000..7891bab09
--- /dev/null
+++ b/src/test/ui/nll/relate_tys/hr-fn-aaa-as-aba.rs
@@ -0,0 +1,24 @@
+// Test that the NLL `relate_tys` code correctly deduces that a
+// function returning either argument CANNOT be upcast to one
+// that returns always its first argument.
+//
+// compile-flags:-Zno-leak-check
+
+fn make_it() -> for<'a> fn(&'a u32, &'a u32) -> &'a u32 {
+    panic!()
+}
+
+fn foo() {
+    let a: for<'a, 'b> fn(&'a u32, &'b u32) -> &'a u32 = make_it();
+    //~^ ERROR mismatched types [E0308]
+    drop(a);
+}
+
+fn bar() {
+    // The code path for patterns is mildly different, so go ahead and
+    // test that too:
+    let _: for<'a, 'b> fn(&'a u32, &'b u32) -> &'a u32 = make_it();
+    //~^ ERROR mismatched types [E0308]
+}
+
+fn main() {}