Cleanup with_stmt.

jedi/evaluate/finder.py

@@ -192,7 +192,7 @@ def _name_to_types(evaluator, context, tree_name):
     elif typ == 'expr_stmt':
         types = _remove_statements(evaluator, context, node, tree_name)
     elif typ == 'with_stmt':
-        types = context.eval_node(node.node_from_name(tree_name))
+        types = context.eval_node(node.get_context_manager_from_name(tree_name))
     elif typ in ('import_from', 'import_name'):
         types = imports.infer_import(context, tree_name)
     elif typ in ('funcdef', 'classdef'):

jedi/parser/python/tree.py

@@ -789,11 +789,10 @@ class WithStmt(Flow):
                 names += _defined_names(with_item.children[2])
         return names
 
-    def node_from_name(self, name):
-        node = name
-        while True:
-            node = node.parent
-            if node.type == 'with_item':
+    def get_context_manager_from_name(self, name):
+        node = name.parent
+        if node.type != 'with_item':
+            raise ValueError('The name is not actually part of a with statement.')
         return node.children[0]