--- a/UnaryNode.st	Wed Nov 23 16:56:51 2016 +0100
+++ b/UnaryNode.st	Fri Nov 25 20:18:05 2016 +0100
@@ -248,9 +248,11 @@
         ].
 
         (Smalltalk includesKey:selectorSymbol) ifTrue:[
-            (aParser alreadyWarnedUnimplementedSelectors includes:selectorSymbol) ifFalse:[
-                aParser alreadyWarnedUnimplementedSelectors add:selectorSymbol.
-                ^ 'funny selector: ',selectorSymbol allBold,' (known as global); possible missing ''.'' or keyword-colon.'
+            ( #( void ) includes:selectorSymbol) ifFalse:[
+                (aParser alreadyWarnedUnimplementedSelectors includes:selectorSymbol) ifFalse:[
+                    aParser alreadyWarnedUnimplementedSelectors add:selectorSymbol.
+                    ^ 'funny selector: ',selectorSymbol allBold,' (known as global); possible missing ''.'' or keyword-colon.'
+                ].
             ].
         ].
     ].