diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index a5efab9..8886d86 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -829,7 +829,7 @@ def err_enumerator_too_large : Error<
 def err_enumerator_wrapped : Error<
   "enumerator value %0 is not representable in the underlying type %1">;
 def err_enum_redeclare_type_mismatch : Error<
-  "enumeration redeclared with different underlying type">;
+  "enumeration redeclared with different underlying type %0 (was %1)">;
 def err_enum_redeclare_fixed_mismatch : Error<
   "enumeration previously declared with %select{non|}0fixed underlying type">;
 def err_enum_redeclare_scoped_mismatch : Error<
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 5c49de4..1a8f67b 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -5669,7 +5669,9 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                 T = QualType(EnumUnderlying.get<const Type*>(), 0);
 
             if (!Context.hasSameUnqualifiedType(T, PrevEnum->getIntegerType())) {
-              Diag(KWLoc, diag::err_enum_redeclare_type_mismatch);
+              Diag(KWLoc, diag::err_enum_redeclare_type_mismatch)
+                << T
+                << PrevEnum->getIntegerType();
               Diag(PrevTagDecl->getLocation(), diag::note_previous_use);
               return PrevTagDecl;
             }
-- 
1.7.2.2