Fix a bug in the `compiler` package that caused invalid code to be

generated for generator expressions.

Lib/compiler/ast.py

@@ -583,11 +583,9 @@ class GenExpr(Node):
     def __init__(self, code, lineno=None):
         self.code = code
         self.lineno = lineno
-        self.argnames = ['[outmost-iterable]']
+        self.argnames = ['.0']
         self.varargs = self.kwargs = None
 
-
-
     def getChildren(self):
         return self.code,