Add Definition.execute, fixes #1076

CHANGELOG.rst

@@ -18,6 +18,8 @@ New APIs:
 - ``Signature.params -> List[ParamDefinition]``, ParamDefinition has the
   following attributes ``infer_default()``, ``infer_annotation()``,
   ``to_string()``, and ``kind``.
+- ``Definition.execute() -> List[Definition]``, makes it possible to infer
+    return values of functions.
 
 
 0.14.1 (2019-07-13)

jedi/api/classes.py

@@ -398,6 +398,9 @@ class BaseDefinition(object):
     def get_signatures(self):
         return [Signature(self._evaluator, s) for s in self._name.infer().get_signatures()]
 
+    def execute(self):
+        return _contexts_to_definitions(self._name.infer().execute_evaluated())
+
 
 class Completion(BaseDefinition):
     """

test/test_api/test_classes.py

@@ -442,3 +442,20 @@ def test_builtin_module_with_path(Script):
     assert semlock.name == 'SemLock'
     assert semlock.line is None
     assert semlock.column is None
+
+
+@pytest.mark.parametrize(
+    'code, description', [
+        ('int', 'instance int'),
+        ('str.index', 'instance int'),
+        ('1', None),
+    ]
+)
+def test_execute(Script, code, description):
+    definition, = Script(code).goto_assignments()
+    definitions = definition.execute()
+    if description is None:
+        assert not definitions
+    else:
+        d, = definitions
+        assert d.description == description