fix a few nasty bugs

jedi/evaluate/dynamic.py

@@ -492,5 +492,5 @@ def _check_isinstance_type(evaluator, stmt, search_name):
         else:
             result.append(c)
     for i, c in enumerate(result):
-        result[i] = er.Instance(c)
+        result[i] = er.Instance(evaluator, c)
     return result

jedi/evaluate/representation.py

@@ -196,6 +196,7 @@ class InstanceElement(use_metaclass(CachedMetaClass, pr.Base)):
     variable (e.g. self.variable or class methods).
     """
     def __init__(self, evaluator, instance, var, is_class_var=False):
+        self._evaluator = evaluator
         if isinstance(var, pr.Function):
             var = Function(evaluator, var)
         elif isinstance(var, pr.Class):