--- a/Parser.st	Tue Dec 03 16:39:04 2019 +0100
+++ b/Parser.st	Tue Dec 03 23:01:30 2019 +0100
@@ -13236,7 +13236,7 @@
     ].
 
     cParser := CParser new.
-    cParser addDefinitions:dictionaryOfTypesOrNil.
+    dictionaryOfTypesOrNil notNil ifTrue:[ cParser addDefinitions:dictionaryOfTypesOrNil ].
     cParser allowRedefinitions:true.
     cParser source:aStream scannerClass:CDeclScanner.
     cParser nextToken.