--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/PCH/cxx11-user-defined-literals.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -pedantic-errors -std=c++11 -emit-pch %s -o %t
+// RUN: %clang_cc1 -pedantic-errors -std=c++11 -include-pch %t -verify %s
+
+#ifndef HEADER_INCLUDED
+
+#define HEADER_INCLUDED
+
+using size_t = decltype(sizeof(int));
+int operator"" _foo(const char *p, size_t);
+
+template<typename T> auto f(T t) -> decltype(t + ""_foo) { return 0; }
+
+#else
+
+int j = ""_foo;
+int k = f(0);
+int *l = f(&k);
+struct S {};
+int m = f(S()); // expected-error {{no matching}}
+                // expected-note@11 {{substitution failure}}
+
+#endif