Fix a small issue that coul dhappen e.g. in stdin.

jedi/evaluate/compiled/mixed.py

@@ -3,6 +3,7 @@ Used only for REPL Completion.
 """
 
 import inspect
+import os
 
 from jedi import common
 from jedi.parser.fast import FastParser
@@ -105,7 +106,8 @@ def find_syntax_node_name(evaluator, python_object):
     except TypeError:
         # The type might not be known (e.g. class_with_dict.__weakref__)
         return None
-    if path is None:
+    if path is None or not os.path.exists(path):
+        # The path might not exist or be e.g. <stdin>.
         return None
 
     module = _load_module(evaluator, path, python_object)

test/test_parser/test_parser.py

@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 import sys
+from textwrap import dedent
 
 import jedi
 from jedi._compatibility import u, is_py3
 from jedi.parser import ParserWithRecovery, load_grammar
 from jedi.parser import tree as pt
-from textwrap import dedent
 
 
 def test_user_statement_on_import():