Fix a bug for dunder methods inference of function objectsfix-crash-in-dunder-inference

Fixes #819

3 files changed, 16 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 560544be..144afdf8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -15,6 +15,10 @@ Release Date: TBA
 
   Fixes PyCQA/pylint#3640
 
+* Fix a bug for dunder methods inference of function objects
+
+  Fixes #819
+
 * Fixes a bug in the signature of the ``ndarray.__or__`` method,
   in the ``brain_numpy_ndarray.py`` module.
 
diff --git a/astroid/interpreter/objectmodel.py b/astroid/interpreter/objectmodel.py
index 3eca5722..ae48ac11 100644
--- a/astroid/interpreter/objectmodel.py
+++ b/astroid/interpreter/objectmodel.py
@@ -324,6 +324,7 @@ class FunctionModel(ObjectModel):
                     doc=func.doc,
                     lineno=func.lineno,
                     col_offset=func.col_offset,
+                    parent=func.parent,
                 )
                 # pylint: disable=no-member
                 new_func.postinit(func.args, func.body, func.decorators, func.returns)
diff --git a/tests/unittest_regrtest.py b/tests/unittest_regrtest.py
index 17668edd..b75e3dfe 100644
--- a/tests/unittest_regrtest.py
+++ b/tests/unittest_regrtest.py
@@ -343,5 +343,16 @@ def test_ancestor_looking_up_redefined_function():
     assert isinstance(found[0], nodes.FunctionDef)
 
 
+def test_crash_in_dunder_inference_prevented():
+    code = """
+    class MyClass():
+        def fu(self, objects):
+            delitem = dict.__delitem__.__get__(self, dict)
+            delitem #@
+    """
+    inferred = next(extract_node(code).infer())
+    assert "builtins.dict.__delitem__" == inferred.qname()
+
+
 if __name__ == "__main__":
     unittest.main()