Add missing perfect forwarding in bound_mem_functor::operator()

slavaandrejev · kjellahl · commit a4883790100b · 2021-12-23T10:18:18.000+01:00
This is a missed addition to the commit that allowed rvalue references
in slot parameters.
diff --git a/sigc++/functors/mem_fun.h b/sigc++/functors/mem_fun.h
@@ -149,7 +149,9 @@ class bound_mem_functor : mem_functor<T_func, T_arg...>
    */
   decltype(auto) operator()(type_trait_take_t<T_arg>... a) const
   {
-    return std::invoke(this->func_ptr_, obj_.invoke(), a...);
+    return std::invoke(
+      this->func_ptr_, obj_.invoke(),
+      std::forward<type_trait_take_t<T_arg>>(a)...);
   }
 
   // protected:
diff --git a/tests/test_rvalue_ref.cc b/tests/test_rvalue_ref.cc
@@ -16,6 +16,12 @@ struct foo
   void operator()(MoveableStruct&& /* x */) { result_stream << "foo(MoveableStruct&&)"; }
 };
 
+struct A
+{
+  void foo(MoveableStruct &&) { result_stream << "A::foo(MoveableStruct&&)"; }
+};
+
+
 } // end anonymous namespace
 
 void
@@ -40,6 +46,17 @@ test_slot()
   util->check_result(result_stream, "foo(MoveableStruct&&)");
 }
 
+void
+test_mem_fun()
+{
+  sigc::slot<void(MoveableStruct &&)> slot;
+  A a;
+  slot = sigc::mem_fun(a, &A::foo);
+  MoveableStruct x;
+  slot(std::move(x));
+  util->check_result(result_stream, "A::foo(MoveableStruct&&)");
+}
+
 int
 main(int argc, char* argv[])
 {
@@ -49,6 +66,7 @@ main(int argc, char* argv[])
 
   test_signal();
   test_slot();
+  test_mem_fun();
 
   return util->get_result_and_delete_instance() ? EXIT_SUCCESS : EXIT_FAILURE;
 } // end main()

Original file line number	Diff line number	Diff line change
`@@ -149,7 +149,9 @@ class bound_mem_functor : mem_functor<T_func, T_arg...>`
`149`	`149`	`*/`
`150`	`150`	`decltype(auto) operator()(type_trait_take_t<T_arg>... a) const`
`151`	`151`	`{`
`152`		`- return std::invoke(this->func_ptr_, obj_.invoke(), a...);`
	`152`	`+ return std::invoke(`
	`153`	`+ this->func_ptr_, obj_.invoke(),`
	`154`	`+ std::forward<type_trait_take_t<T_arg>>(a)...);`
`153`	`155`	`}`
`154`	`156`
`155`	`157`	`// protected:`