diff --git a/unittests/ADT/FunctionRefTest.cpp b/unittests/ADT/FunctionRefTest.cpp
index f084aa7a660..47633cada0f 100644
--- a/unittests/ADT/FunctionRefTest.cpp
+++ b/unittests/ADT/FunctionRefTest.cpp
@@ -49,9 +49,9 @@ TEST(FunctionRefTest, BadCopy) {
 }
 
 // Test that overloads on function_refs are resolved as expected.
-const char *returns(StringRef) { return "not a function"; }
-const char *returns(function_ref<double()> F) { return "number"; }
-const char *returns(function_ref<StringRef()> F) { return "string"; }
+std::string returns(StringRef) { return "not a function"; }
+std::string returns(function_ref<double()> F) { return "number"; }
+std::string returns(function_ref<StringRef()> F) { return "string"; }
 
 TEST(FunctionRefTest, SFINAE) {
   EXPECT_EQ("not a function", returns("boo!"));