From 18ad5a594ec4ee039897eb03d90dfeb117b4c6d6 Mon Sep 17 00:00:00 2001
From: Yuki Okushi <huyuumi.dev@gmail.com>
Date: Wed, 19 Aug 2020 17:19:21 +0900
Subject: [PATCH] Add a regression test for issue-72793

---
 .../ui/type-alias-impl-trait/issue-72793.rs   | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 src/test/ui/type-alias-impl-trait/issue-72793.rs

diff --git a/src/test/ui/type-alias-impl-trait/issue-72793.rs b/src/test/ui/type-alias-impl-trait/issue-72793.rs
new file mode 100644
index 000000000000..e643a8cab5b0
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/issue-72793.rs
@@ -0,0 +1,27 @@
+// build-pass
+
+// Regression test for #72793.
+// FIXME: This still shows ICE with `-Zmir-opt-level=2`.
+
+#![feature(type_alias_impl_trait)]
+
+trait T { type Item; }
+
+type Alias<'a> = impl T<Item = &'a ()>;
+
+struct S;
+impl<'a> T for &'a S {
+    type Item = &'a ();
+}
+
+fn filter_positive<'a>() -> Alias<'a> {
+    &S
+}
+
+fn with_positive(fun: impl Fn(Alias<'_>)) {
+    fun(filter_positive());
+}
+
+fn main() {
+    with_positive(|_| ());
+}