core: Make variable shadowing a compile-time error

Now that we have most of core free of shadowing, we can enable the
warning as an error to catch anything that may be remaining and also
eliminate this class of logic bug entirely.

src/core/hle/service/service.h

@@ -155,17 +155,17 @@ protected:
         /**
          * Constructs a FunctionInfo for a function.
          *
-         * @param expected_header request header in the command buffer which will trigger dispatch
+         * @param expected_header_ request header in the command buffer which will trigger dispatch
          *     to this handler
-         * @param handler_callback member function in this service which will be called to handle
+         * @param handler_callback_ member function in this service which will be called to handle
          *     the request
-         * @param name human-friendly name for the request. Used mostly for logging purposes.
+         * @param name_ human-friendly name for the request. Used mostly for logging purposes.
          */
-        FunctionInfo(u32 expected_header, HandlerFnP<Self> handler_callback, const char* name)
+        FunctionInfo(u32 expected_header_, HandlerFnP<Self> handler_callback_, const char* name_)
             : FunctionInfoBase{
-                  expected_header,
+                  expected_header_,
                   // Type-erase member function pointer by casting it down to the base class.
-                  static_cast<HandlerFnP<ServiceFrameworkBase>>(handler_callback), name} {}
+                  static_cast<HandlerFnP<ServiceFrameworkBase>>(handler_callback_), name_} {}
     };
 
     /**