Merge pull request #7162 from apple/disable-duplicate-definition

Add a flag to disable "duplicate definition of category" warnings

Author: ahatanaka

clang/include/clang/Basic/DiagnosticCommonKinds.td

@@ -293,7 +293,8 @@ def warn_slh_does_not_support_asm_goto : Warning<
 
 // Sema && Serialization
 def warn_dup_category_def : Warning<
-  "duplicate definition of category %1 on interface %0">;
+  "duplicate definition of category %1 on interface %0">,
+  InGroup<DiagGroup<"objc-duplicate-category-definition">>;
 
 // Targets
 

clang/test/Misc/warning-flags.c

@@ -18,7 +18,7 @@ This test serves two purposes:
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (66):
+CHECK: Warnings without flags (65):
 
 CHECK-NEXT:   ext_expected_semi_decl_list
 CHECK-NEXT:   ext_explicit_specialization_storage_class
@@ -46,7 +46,6 @@ CHECK-NEXT:   warn_double_const_requires_fp64
 CHECK-NEXT:   warn_drv_assuming_mfloat_abi_is
 CHECK-NEXT:   warn_drv_clang_unsupported
 CHECK-NEXT:   warn_drv_pch_not_first_include
-CHECK-NEXT:   warn_dup_category_def
 CHECK-NEXT:   warn_enum_value_overflow
 CHECK-NEXT:   warn_expected_qualified_after_typename
 CHECK-NEXT:   warn_fe_backend_unsupported

clang/test/SemaObjC/check-dup-objc-decls-1.m

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class -Wno-objc-duplicate-category-definition -DIGNORE_DUP_CAT %s
 
 @interface Foo // expected-note {{previous definition is here}}
 @end
@@ -41,8 +42,13 @@ @protocol DP<P> @end
 @protocol DP<Q> @end
 #pragma clang diagnostic pop
 
-@interface A(Cat)<P> @end // expected-note {{previous definition is here}}
-@interface A(Cat)<Q> @end // expected-warning {{duplicate definition of category 'Cat' on interface 'A'}}
+@interface A(Cat)<P> @end
+@interface A(Cat)<Q> @end
+
+#ifndef IGNORE_DUP_CAT
+// expected-note@-4 {{previous definition is here}}
+// expected-warning@-4 {{duplicate definition of category 'Cat' on interface 'A'}}
+#endif
 
 // rdar 7626768
 @class NSString;