diff --git a/src/MacVim/gui_macvim.m b/src/MacVim/gui_macvim.m
index 92fe03d06b..264948a767 100644
--- a/src/MacVim/gui_macvim.m
+++ b/src/MacVim/gui_macvim.m
@@ -1597,7 +1597,7 @@ gui_mch_get_color(char_u *name)
 /*
  * Return the RGB value of a pixel as long.
  */
-    long_u
+    guicolor_T
 gui_mch_get_rgb(guicolor_T pixel)
 {
     // This is only implemented so that vim can guess the correct value for
diff --git a/src/proto/gui_macvim.pro b/src/proto/gui_macvim.pro
index aa002e54c0..997e3d640c 100644
--- a/src/proto/gui_macvim.pro
+++ b/src/proto/gui_macvim.pro
@@ -121,7 +121,7 @@ gui_mch_enable_scrollbar(
 gui_mch_flash(int msec);
     guicolor_T
 gui_mch_get_color(char_u *name);
-    long_u
+    guicolor_T
 gui_mch_get_rgb(guicolor_T pixel);
     void
 gui_mch_get_screen_dimensions(int *screen_w, int *screen_h);