Small function/param corrections.

jedi/evaluate/param.py

@@ -186,7 +186,7 @@ def get_params(evaluator, func, var_args):
             if va_values:
                 values = va_values
             else:
-                if param.assignment_details:
+                if param.default is not None:
                     # No value: Return the default values.
                     has_default_value = True
                     result.append(param.get_name())

jedi/evaluate/representation.py

@@ -487,6 +487,9 @@ class Function(use_metaclass(CachedMetaClass, Wrapper)):
             f = Function(self._evaluator, f, True)
         return f
 
+    def scope_names_generator(self, position=None):
+        yield self, self.get_magic_function_names()
+
     def get_decorated_func(self):
         """
         This function exists for the sole purpose of returning itself if the