diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 7225aadbbc1e..448f16b0b820 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -740,9 +740,9 @@ def warn_missing_prototype : Warning<
   InGroup<DiagGroup<"missing-prototypes">>, DefaultIgnore;
 def err_redefinition : Error<"redefinition of %0">;
 
-def warn_redefinition_of_typedef : Warning<
+def warn_redefinition_of_typedef : ExtWarn<
   "redefinition of typedef %0 is invalid in C">,
-  InGroup<DiagGroup<"typedef-redefinition"> >, DefaultError;
+  InGroup<DiagGroup<"typedef-redefinition"> >;
 
 def err_static_non_static : Error<
   "static declaration of %0 follows non-static declaration">;
diff --git a/clang/test/Preprocessor/line-directive.c b/clang/test/Preprocessor/line-directive.c
index a9ed4bcf8cd6..53e9ab7b5de9 100644
--- a/clang/test/Preprocessor/line-directive.c
+++ b/clang/test/Preprocessor/line-directive.c
@@ -41,7 +41,7 @@
 
 # 192 "glomp.h" // not a system header.
 typedef int x;  // expected-note {{previous definition is here}}
-typedef int x;  // expected-error {{redefinition of typedef 'x' is invalid in C}}
+typedef int x;  // expected-warning {{redefinition of typedef 'x' is invalid in C}}
 
 # 192 "glomp.h" 3 // System header.
 typedef int y;  // ok
@@ -60,7 +60,7 @@ typedef int z1;  // ok
 # 42 "blonk.h"  // DOES change system headerness.
 
 typedef int w;  // expected-note {{previous definition is here}}
-typedef int w;  // expected-error {{redefinition of typedef 'w' is invalid in C}}
+typedef int w;  // expected-warning {{redefinition of typedef 'w' is invalid in C}}
 
 
 // This should not produce an "extra tokens at end of #line directive" warning,