--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/warn/pr94038.C	Mon May 25 07:50:57 2020 +0900
@@ -0,0 +1,26 @@
+// PR c++/94038
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-O -Wall" }
+
+template<typename T>
+constexpr int
+foo()
+{
+  static_assert(T(1) == 0, "");
+  return 0;
+}
+
+template<typename T>
+constexpr int
+bar()
+{
+  return foo<T>();
+}
+
+constexpr int
+baz(int a)
+{
+  return a;
+}
+
+static_assert(decltype(baz(bar<int>())){} == 0, "");