Replace get_all_import_names with a leaf search method in Simple.

jedi/api/helpers.py

@@ -25,22 +25,9 @@ def get_on_import_stmt(evaluator, user_context, user_stmt, is_like_search=False)
     Resolve the user statement, if it is an import. Only resolve the
     parts until the user position.
     """
-    import_names = user_stmt.get_all_import_names()
-    kill_count = -1
-    cur_name_part = None
-    for name in import_names:
-        if user_stmt.alias == name:
-            continue
+    name = user_stmt.leaf_for_position(user_context.position)
+    if name is None:
+        raise NotImplementedError
 
-        if name.end_pos >= user_context.position:
-            if not cur_name_part:
-                cur_name_part = name
-            kill_count += 1
-
-    context = user_context.get_context()
-    just_from = next(context) == 'from'
-
-    i = imports.ImportWrapper(evaluator, user_stmt, is_like_search,
-                              kill_count=kill_count, nested_resolve=True,
-                              is_just_from=just_from)
-    return i, cur_name_part
+    i = imports.ImportWrapper(evaluator, name)
+    return i, name