From 946cb11a1ebeabb5b170e58c87787a24693251e9 Mon Sep 17 00:00:00 2001
From: Bastian Kauschke <bastian_kauschke@hotmail.de>
Date: Thu, 16 Jul 2020 12:32:43 +0200
Subject: [PATCH] add regression test for #73120

---
 .../issues/auxiliary/const_generic_issues_lib.rs   | 14 ++++++++++++++
 src/test/ui/const-generics/issues/issue-73120.rs   |  8 ++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 src/test/ui/const-generics/issues/auxiliary/const_generic_issues_lib.rs
 create mode 100644 src/test/ui/const-generics/issues/issue-73120.rs

diff --git a/src/test/ui/const-generics/issues/auxiliary/const_generic_issues_lib.rs b/src/test/ui/const-generics/issues/auxiliary/const_generic_issues_lib.rs
new file mode 100644
index 0000000000000..59a4d345cbccb
--- /dev/null
+++ b/src/test/ui/const-generics/issues/auxiliary/const_generic_issues_lib.rs
@@ -0,0 +1,14 @@
+#![feature(const_generics)]
+
+// All of these three items must be in `lib2` to reproduce the error
+
+pub trait TypeFn {
+    type Output;
+}
+
+pub struct GenericType<const B: i8>;
+
+// Removing the braces around `42` resolves the crash
+impl TypeFn for GenericType<{ 42 }> {
+    type Output = ();
+}
diff --git a/src/test/ui/const-generics/issues/issue-73120.rs b/src/test/ui/const-generics/issues/issue-73120.rs
new file mode 100644
index 0000000000000..aea4de39f79ce
--- /dev/null
+++ b/src/test/ui/const-generics/issues/issue-73120.rs
@@ -0,0 +1,8 @@
+// check-pass
+// aux-build:const_generic_issues_lib.rs
+extern crate const_generic_issues_lib as lib2;
+fn unused_function(
+    _: <lib2::GenericType<42> as lib2::TypeFn>::Output
+) {}
+
+fn main() {}