1 files changed, 27 insertions, 0 deletions
diff --git a/src/test/ui/extern/extern-compare-with-return-type.rs b/src/test/ui/extern/extern-compare-with-return-type.rs
new file mode 100644
index 000000000..42693d3a0
--- /dev/null
+++ b/src/test/ui/extern/extern-compare-with-return-type.rs
@@ -0,0 +1,27 @@
+// run-pass
+
+// Tests that we can compare various kinds of extern fn signatures.
+#![allow(non_camel_case_types)]
+
+// `dbg!()` differentiates these functions to ensure they won't be merged.
+extern "C" fn voidret1() { dbg!() }
+extern "C" fn voidret2() { dbg!() }
+
+extern "C" fn uintret() -> usize { 22 }
+
+extern "C" fn uintvoidret(_x: usize) {}
+
+extern "C" fn uintuintuintuintret(x: usize, y: usize, z: usize) -> usize { x+y+z }
+type uintuintuintuintret = extern "C" fn(usize,usize,usize) -> usize;
+
+pub fn main() {
+    assert!(voidret1 as extern "C" fn() == voidret1 as extern "C" fn());
+    assert!(voidret1 as extern "C" fn() != voidret2 as extern "C" fn());
+
+    assert!(uintret as extern "C" fn() -> usize == uintret as extern "C" fn() -> usize);
+
+    assert!(uintvoidret as extern "C" fn(usize) == uintvoidret as extern "C" fn(usize));
+
+    assert!(uintuintuintuintret as uintuintuintuintret ==
+            uintuintuintuintret as uintuintuintuintret);
+}