Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -739,7 +739,8 @@
   "trying to recursively use %0 as superclass of %1">;
 def err_conflicting_aliasing_type : Error<"conflicting types for alias %0">;
 def warn_undef_interface : Warning<"cannot find interface declaration for %0">;
-def warn_duplicate_protocol_def : Warning<"duplicate protocol definition of %0 is ignored">;
+def warn_duplicate_protocol_def : Warning<"duplicate protocol definition of %0 is ignored">,
+  InGroup<DiagGroup<"duplicate-protocol">>;
 def err_protocol_has_circular_dependency : Error<
   "protocol has circular dependency">;
 def err_undeclared_protocol : Error<"cannot find protocol declaration for %0">;
Index: test/Misc/warning-flags.c
===================================================================
--- test/Misc/warning-flags.c
+++ test/Misc/warning-flags.c
@@ -18,7 +18,7 @@
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (83):
+CHECK: Warnings without flags (82):
 CHECK-NEXT:   ext_excess_initializers
 CHECK-NEXT:   ext_excess_initializers_in_char_array_initializer
 CHECK-NEXT:   ext_expected_semi_decl_list
@@ -58,7 +58,6 @@
 CHECK-NEXT:   warn_drv_objc_gc_unsupported
 CHECK-NEXT:   warn_drv_pch_not_first_include
 CHECK-NEXT:   warn_dup_category_def
-CHECK-NEXT:   warn_duplicate_protocol_def
 CHECK-NEXT:   warn_enum_value_overflow
 CHECK-NEXT:   warn_expected_qualified_after_typename
 CHECK-NEXT:   warn_extraneous_char_constant