BLI: fix overload resolution with FunctionRef parameters

source/blender/blenlib/BLI_function_ref.hh

@@ -111,7 +111,8 @@ template<typename Ret, typename... Params> class FunctionRef<Ret(Params...)> {
    */
   template<typename Callable,
            BLI_ENABLE_IF((
-               !std::is_same_v<std::remove_cv_t<std::remove_reference_t<Callable>>, FunctionRef>))>
+               !std::is_same_v<std::remove_cv_t<std::remove_reference_t<Callable>>, FunctionRef>)),
+           BLI_ENABLE_IF((std::is_invocable_r_v<Ret, Callable, Params...>))>
   FunctionRef(Callable &&callable)
       : callback_(callback_fn<typename std::remove_reference_t<Callable>>),
         callable_(intptr_t(&callable))

source/blender/blenlib/tests/BLI_function_ref_test.cc

@@ -130,4 +130,23 @@ TEST(function_ref, InitializeWithNull)
   EXPECT_FALSE(f);
 }
 
+static int overload_test(const FunctionRef<void(std::string)> /*fn*/)
+{
+  return 1;
+}
+
+static int overload_test(const FunctionRef<void(int)> /*fn*/)
+{
+  return 2;
+}
+
+TEST(function_ref, OverloadSelection)
+{
+  const auto fn_1 = [](std::string /*x*/) {};
+  const auto fn_2 = [](int /*x*/) {};
+
+  EXPECT_EQ(overload_test(fn_1), 1);
+  EXPECT_EQ(overload_test(fn_2), 2);
+}
+
 }  // namespace blender::tests