Function overload check cleanup. Added if statement to parsing.

test/parse/custom_hint.golden

@@ -0,0 +1,12 @@
+(program	
+ (properties p
+  [(:= time float (@time))])
+
+ (fun vertex vs_main -> float4 (@position)
+  [(:= pos float3 (@position))] 
+  (return (float4 pos.x pos.y pos.z 1)))
+
+ (fun pixel ps_main -> float4 (@target)
+  [(:= pos float4 (@outposition))] 
+  (:= t p.time) 
+  (return (float4 1 1 1 1))))