Fix bytes issue with file path adding

jedi/api/file_name.py

@@ -1,6 +1,6 @@
 import os
 
-from jedi._compatibility import FileNotFoundError
+from jedi._compatibility import FileNotFoundError, force_unicode
 from jedi.evaluate.names import AbstractArbitraryName
 from jedi.api import classes
 from jedi.evaluate.helpers import get_str_or_none
@@ -54,7 +54,7 @@ def _get_string_additions(module_context, start_leaf):
             s = get_str_or_none(c)
             if s is None:
                 return string
-            string = s + string
+            string = force_unicode(s) + string
             continue
 
         if child_node != '+':

jedi/evaluate/context/module.py

@@ -27,8 +27,9 @@ class _ModuleAttributeName(AbstractNameDefinition):
     def infer(self):
         if self._string_value is not None:
             s = self._string_value
-            if self.parent_context.evaluator.environment.version_info.major == 2:
-                s = bytes(s)
+            if self.parent_context.evaluator.environment.version_info.major == 2 \
+                    and not isinstance(s, bytes):
+                s = bytes(s, 'utf-8')
             return ContextSet([
                 create_simple_object(self.parent_context.evaluator, s)
             ])