Make nested dict completions possible.

See also ipython/ipython#13866

jedi/api/strings.py

@@ -36,8 +36,11 @@ def complete_dict(module_context, code_lines, leaf, position, string, fuzzy):
             string = cut_value_at_position(leaf, position)
 
         context = module_context.create_context(bracket_leaf)
-        before_bracket_leaf = bracket_leaf.get_previous_leaf()
-        if before_bracket_leaf.type in ('atom', 'trailer', 'name'):
+
+        before_node = before_bracket_leaf = bracket_leaf.get_previous_leaf()
+        if before_node in (')', ']', '}'):
+            before_node = before_node.parent
+        if before_node.type in ('atom', 'trailer', 'name'):
             values = infer_call_of_leaf(context, before_bracket_leaf)
             return list(_completions_for_dicts(
                 module_context.inference_state,

test/test_api/test_interpreter.py

@@ -830,3 +830,11 @@ def without_annotation(self):
     # This is a fallback, if the annotations don't help
     _assert_interpreter_complete('p.with_annotation_garbage1.its', namespace, ['its_me'])
     _assert_interpreter_complete('p.with_annotation_garbage2.its', namespace, ['its_me'])
+
+
+def test_nested__getitem__():
+    d = {'foo': {'bar': 1}}
+    _assert_interpreter_complete('d["fo', locals(), ['"foo"'])
+    _assert_interpreter_complete('d["foo"]["ba', locals(), ['"bar"'])
+    _assert_interpreter_complete('(d["foo"])["ba', locals(), ['"bar"'])
+    _assert_interpreter_complete('((d["foo"]))["ba', locals(), ['"bar"'])