@@ -123,9 +123,10 @@ typeToString _ String = return "string"
123123typeToString _ Number = return "number"
124124typeToString _ Boolean = return "boolean"
125125typeToString _ Array = return "array"
126+typeToString _ (TypeVar _) = return "var"
126127typeToString mn (TypeConstructor ty') = return $ qualifiedToString mn ty'
127128typeToString mn (TypeApp ty' (TypeVar _)) = typeToString mn ty'
128−typeToString _ _ = Left "Type class instance must be of the form T a1 ... an"
129+typeToString a b = Left $ "Type class instance must be of the form T a1 ... an " ++ show (a, b)
129130
130131mkDictionaryEntryName :: ModuleName -> Qualified ProperName -> Type -> Ident -> Desugar Ident
131132mkDictionaryEntryName mn name ty ident = do