diff --git a/evaluate.py b/evaluate.py
index a96d0755..3285a82b 100644
--- a/evaluate.py
+++ b/evaluate.py
@@ -284,7 +284,6 @@ class Execution(Executable):
         elif isinstance(self.base, Generator):
             return Execution(self.base.func).get_return_types(True)
         else:
-            # set the callback function to get the var_args
             # don't do this with exceptions, as usual, because some deeper
             # exceptions could be catched - and I wouldn't know what happened.
             if hasattr(self.base, 'returns'):
@@ -315,13 +314,16 @@ class Execution(Executable):
         which act the same way as normal functions.
         """
         def gen_param_name_copy(param, keys=[], values=[], array_type=None):
-            """ Create a param with self as parent. """
-            calls = parsing.Array(parsing.Array.NOARRAY, parent_stmt=self)
+            """
+            Create a param with the original scope (of varargs) as parent.
+            """
+            calls = parsing.Array(parsing.Array.NOARRAY,
+                                            self.var_args.parent_stmt)
             calls.values = values
             calls.keys = keys
             calls.type = array_type
             new_param = copy.copy(param)
-            new_param.parent = self
+            new_param.parent = self.var_args.parent_stmt
             new_param._assignment_calls_calculated = True
             new_param._assignment_calls = calls
             name = copy.copy(param.get_name())
@@ -513,14 +515,15 @@ class Execution(Executable):
 
 
 class Generator(object):
+    # TODO bring next(iter, default) to work - default works not
     def __init__(self, func):
         super(Generator, self).__init__()
         self.func = func
 
     def get_defined_names(self):
         """
-        Returns a list of GeneratorObject, which can return the content of a
-        generator
+        Returns a list of names that define a generator, which can return the
+        content of a generator.
         """
         names = []
         for n in ['__next__', 'send']:
@@ -533,6 +536,7 @@ class Generator(object):
             name = parsing.Name([n], 0, 0, 0)
             name.parent = None
             names.append(name)
+        debug.dbg('generator names', names)
         return names
 
     @property
diff --git a/mixin/__builtin__.py b/mixin/__builtin__.py
index 8d92240d..e39b76dc 100644
--- a/mixin/__builtin__.py
+++ b/mixin/__builtin__.py
@@ -1,5 +1,5 @@
 
-def next(iterator, default=1):
+def next(iterator, default=None):
     if hasattr("next"):
         return iterator.next()
     else:
diff --git a/parsing.py b/parsing.py
index be503500..16aa8cf2 100644
--- a/parsing.py
+++ b/parsing.py
@@ -332,14 +332,6 @@ class Function(Scope):
 
     def get_set_vars(self):
         n = super(Function, self).get_set_vars()
-        """
-        if self.param_cb:
-            # This is the really ugly part, where the functional style of this
-            # get methods is broken, it executes a callback.
-            # This is important, because something has to inject the params
-            # into the functions, with the right values.
-            n += self.param_cb()
-        """
         for p in self.params:
             try:
                 n.append(p.get_name())
diff --git a/test/completion/functions.py b/test/completion/functions.py
index e27bce14..3b33b598 100644
--- a/test/completion/functions.py
+++ b/test/completion/functions.py
@@ -63,7 +63,7 @@ def recursion(a, b):
     else:
         return recursion(a+".", b+1)
 
-##? int() float()
+#? int() float()
 recursion("a", 1.0)
 
 # -----------------
@@ -82,6 +82,16 @@ exe[0].index
 #? ['append']
 exe[1].append
 
+# -----------------
+# default arguments
+# -----------------
+
+##? int() str()
+func()
+
+##? float() str()
+func(1.0)
+
 # -----------------
 # closures
 # -----------------
@@ -255,3 +265,6 @@ next(gen_exe).upper
 next(gen_exe).real
 #? int() str()
 next(gen_exe)
+
+#? int() str() list
+next(gen_exe, list)