Fix two bugs that were raising exceptions

jedi/evaluate/context/typing.py

@@ -133,7 +133,8 @@ class TypingContextWithIndex(_WithIndexBase):
         elif string_name == 'Optional':
             # Optional is basically just saying it's either None or the actual
             # type.
-            return ContextSet(self._context) \
+            # TODO raise a warning if multiple params are given
+            return self._execute_annotations_for_all_indexes() \
                 | ContextSet(builtin_from_name(self.evaluator, u'None'))
         elif string_name == 'Type':
             # The type is actually already given in the index_context

jedi/evaluate/param.py

@@ -48,7 +48,7 @@ def get_executed_params(execution_context, var_args):
     # Default params are part of the context where the function was defined.
     # This means that they might have access on class variables that the
     # function itself doesn't have.
-    default_param_context = execution_context.get_default_param_context()
+    default_param_context = execution_context.function_context.get_default_param_context()
 
     for param in funcdef.get_params():
         param_dict[param.name.value] = param