[Clang] Add support for -Wno-inline-namespace-reopened-noninline

[Elvina]

Summary

This patch adds the option for disabling warn_inline_namespace_reopened_noninline warning described here: https://bugs.llvm.org/show_bug.cgi?id=46106

[Elvina]

Thanks for looking at this. I don't have commit rights, could you please commit the change on my behalf?

[andreybokhanko]

Fix committed in https://reviews.llvm.org/rG16501782c8d849bc1812d527dc8466574700663d. Thanks for working on this!

clang/include/clang/Basic/DiagnosticGroups.td

def NonModularIncludeInFrameworkModule
   : DiagGroup<"non-modular-include-in-framework-module">;
 def NonModularIncludeInModule : DiagGroup<"non-modular-include-in-module",
                                           [NonModularIncludeInFrameworkModule]>;
 def IncompleteModule : DiagGroup<"incomplete-module",
     [IncompleteUmbrella, NonModularIncludeInModule]>;
 def PrivateModule : DiagGroup<"private-module">;
 
 def CXX11InlineNamespace : DiagGroup<"c++11-inline-namespace">;
+def InlineNamespaceReopenedNoninline
+    : DiagGroup<"inline-namespace-reopened-noninline">;
 def InvalidNoreturn : DiagGroup<"invalid-noreturn">;
 def InvalidSourceEncoding : DiagGroup<"invalid-source-encoding">;
 def KNRPromotedParameter : DiagGroup<"knr-promoted-parameter">;
 def : DiagGroup<"init-self">;
 def : DiagGroup<"inline">;
 def : DiagGroup<"invalid-pch">;
 def GNULabelsAsValue : DiagGroup<"gnu-label-as-value">;
 def LiteralRange : DiagGroup<"literal-range">;

clang/include/clang/Basic/DiagnosticSemaKinds.td

 
 def ext_inline_variable : ExtWarn<
   "inline variables are a C++17 extension">, InGroup<CXX17>;
 def warn_cxx14_compat_inline_variable : Warning<
   "inline variables are incompatible with C++ standards before C++17">,
   DefaultIgnore, InGroup<CXXPre17Compat>;
 
 def warn_inline_namespace_reopened_noninline : Warning<
-  "inline namespace reopened as a non-inline namespace">;
+  "inline namespace reopened as a non-inline namespace">,
+  InGroup<InlineNamespaceReopenedNoninline>;
 def err_inline_namespace_mismatch : Error<
   "non-inline namespace cannot be reopened as inline">;
 
 def err_unexpected_friend : Error<
   "friends can only be classes or functions">;
 def ext_enum_friend : ExtWarn<
   "befriending enumeration type %0 is a C++11 extension">, InGroup<CXX11>;
 def warn_cxx98_compat_enum_friend : Warning<

clang/test/Misc/warning-flags.c

(2) It prevents us adding new warnings to Clang that have no -W flag.  All
     new warnings should have -W flags.
 
     If you add a new warning without a flag, this test will fail.  To fix
     this test, simply add a warning group to that warning.
 
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (69):
+CHECK: Warnings without flags (68):
 
 CHECK-NEXT:   ext_expected_semi_decl_list
 CHECK-NEXT:   ext_explicit_specialization_storage_class
 CHECK-NEXT:   ext_missing_declspec
 CHECK-NEXT:   ext_missing_whitespace_after_macro_name
 CHECK-NEXT:   ext_new_paren_array_nonconst
 CHECK-NEXT:   ext_plain_complex
 CHECK-NEXT:   ext_template_arg_extra_parens

 CHECK-NEXT:   warn_extraneous_char_constant
 CHECK-NEXT:   warn_fe_backend_unsupported
 CHECK-NEXT:   warn_fe_cc_log_diagnostics_failure
 CHECK-NEXT:   warn_fe_cc_print_header_failure
 CHECK-NEXT:   warn_fe_macro_contains_embedded_newline
 CHECK-NEXT:   warn_ignoring_ftabstop_value
 CHECK-NEXT:   warn_implements_nscopying
 CHECK-NEXT:   warn_incompatible_qualified_id
-CHECK-NEXT:   warn_inline_namespace_reopened_noninline
 CHECK-NEXT:   warn_invalid_asm_cast_lvalue
 CHECK-NEXT:   warn_maynot_respond
 CHECK-NEXT:   warn_method_param_redefinition
 CHECK-NEXT:   warn_missing_case_for_condition
 CHECK-NEXT:   warn_missing_dependent_template_keyword
 CHECK-NEXT:   warn_missing_whitespace_after_macro_name
 CHECK-NEXT:   warn_mt_message
 CHECK-NEXT:   warn_no_constructor_for_refconst

clang/test/SemaCXX/warn-inline-namespace-reopened-noninline-disable.cpp

+// RUN: %clang_cc1 -fsyntax-only -Wall -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -Wall -Wno-inline-namespace-reopened-noninline -DSILENCE -verify -std=c++11 %s
+
+namespace X {
+  #ifndef SILENCE
+    inline namespace {} // expected-note {{previous definition}}
+    namespace {} // expected-warning {{inline namespace reopened as a non-inline namespace}}
+  #else
+    // expected-no-diagnostics
+    inline namespace {}
+    namespace {}
+  #endif
+}