In bug #147057: ERROR: Source/WebCore/platform/graphics/freetype/UniquePtrFreeType.cpp:27: default_delete::operator is incorrectly named. Don't use underscores in your identifier names. [readability/naming/underscores] [4] ERROR: Source/WebCore/platform/graphics/freetype/UniquePtrFreeType.cpp:32: default_delete::operator is incorrectly named. Don't use underscores in your identifier names. [readability/naming/underscores] [4] ERROR: Source/WebCore/platform/graphics/freetype/UniquePtrFreeType.cpp:37: default_delete::operator is incorrectly named. Don't use underscores in your identifier names. [readability/naming/underscores] [4] Total errors found: 3 in 15 files But these are template specializations of templates that are not declared by WebKit (default_delete is actually in namespace std, but that's irrelevant), so they have to be named that.