def : DiagGroup<"all", [Most, Parentheses]>;
// Aliases.
-def : DiagGroup<"", [Extra]>; // -W = -Wextra
-def : DiagGroup<"endif-labels", [ExtraTokens]>; // endif-labels = endif-tokens
+def : DiagGroup<"", [Extra]>; // -W = -Wextra
+def : DiagGroup<"endif-labels", [ExtraTokens]>; // -Wendif-labels=-Wendif-tokens
+def : DiagGroup<"comments", [Comment]>; // -Wcomments = -Wcomment
// A warning group for warnings that we want to have on by default in clang,
// but which aren't on by default in GCC.