fix specialIdGen to avoid reserved words. Solves #151

Author: marcosh

src/Language/Parser/Generator/Generator.hs

@@ -51,7 +51,10 @@ lowerIdGen =
       (`notElem` reservedWords)
 
 specialIdGen :: Gen String
-specialIdGen = (:) <$> idCharGen <*> listOf (oneof [idCharGen, digitCharGen])
+specialIdGen =
+  ((:) <$> idCharGen <*>
+    listOf (oneof [idCharGen, digitCharGen])) `suchThat`
+      (`notElem` reservedWords)
 
 identifierGen :: Gen String
 identifierGen = oneof [lowerIdGen, upperIdGen, specialIdGen]