def ImplicitFunctionDeclare : DiagGroup<"implicit-function-declaration">;
def Trigraphs : DiagGroup<"trigraphs">;
+// Empty DiagGroups: these are recognized by clang but ignored.
+def : DiagGroup<"extra">;
+def : DiagGroup<"">; // -W
+
+
+
// driver has stripped off -Wa,foo etc. The driver has also translated -W to
// -Wextra, so we don't need to worry about it.
static llvm::cl::list<std::string>
-OptWarnings("W", llvm::cl::Prefix);
+OptWarnings("W", llvm::cl::Prefix, llvm::cl::ValueOptional);
static llvm::cl::opt<bool> OptPedantic("pedantic");
static llvm::cl::opt<bool> OptPedanticErrors("pedantic-errors");