Erase impl regions when checking for impossible to eagerly monomorphize items

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/ui/codegen/mono-impossible-2.rs b/tests/ui/codegen/mono-impossible-2.rs
new file mode 100644
index 00000000000..21eb2c9b2f2
--- /dev/null
+++ b/tests/ui/codegen/mono-impossible-2.rs
@@ -0,0 +1,19 @@
+//compile-flags: --crate-type=lib -Clink-dead-code=on
+// build-pass
+
+// Make sure that we don't monomorphize the impossible method `<() as Visit>::visit`,
+// which does not hold under a reveal-all param env.
+
+pub trait Visit {
+    fn visit() {}
+}
+
+pub trait Array {
+    type Element;
+}
+
+impl<'a> Visit for () where (): Array<Element = &'a ()> {}
+
+impl Array for () {
+    type Element = ();
+}