diff --git a/gfx/2d/Types.h b/gfx/2d/Types.h
index 63545946c2..6fb9d955db 100644
--- a/gfx/2d/Types.h
+++ b/gfx/2d/Types.h
@@ -397,9 +397,9 @@ enum SideBits {
   for (mozilla::Side var_;                                          \
        MOZ_CONCAT(var_,__LINE__) <= mozilla::eSideLeft &&           \
          ((var_ = mozilla::Side(MOZ_CONCAT(var_,__LINE__))), true); \
-       MOZ_CONCAT(var_,__LINE__)++)
+       ++MOZ_CONCAT(var_,__LINE__))
 
-static inline Side operator++(Side& side, int) {
+static inline Side& operator++(Side& side) {
   MOZ_ASSERT(side >= eSideTop && side <= eSideLeft,
              "Out of range side");
   side = Side(side + 1);