Basic implementation support for namedexpr, fixes #1647

jedi/inference/__init__.py

@@ -170,6 +170,8 @@ class InferenceState:
                 return tree_name_to_values(self, context, name)
             elif type_ == 'param':
                 return context.py__getattribute__(name.value, position=name.end_pos)
+            elif type_ == 'namedexpr_test':
+                return context.infer_node(def_)
         else:
             result = follow_error_node_imports_if_possible(context, name)
             if result is not None:

jedi/inference/syntax_tree.py

@@ -753,6 +753,8 @@ def tree_name_to_values(inference_state, context, tree_name):
         types = NO_VALUES
     elif typ == 'del_stmt':
         types = NO_VALUES
+    elif typ == 'namedexpr_test':
+        types = infer_node(context, node)
     else:
         raise ValueError("Should not happen. type: %s" % typ)
     return types