Correctly instantiate exception instances when inferring their attrib…

…utes with objectmodel

Close pylint-dev/pylint#2776

ChangeLog

@@ -10,6 +10,11 @@ Release Date: TBA
 
  Close PyCQA/pylint#2770
 
+* Correctly instantiate exception instances when inferring their attributes with objectmodel
+
+ Close PyCQA/pylint#2776
+
+
 What's New in astroid 2.2.0?
 ============================
 Release Date: 2019-02-27

astroid/objects.py

@@ -216,7 +216,7 @@ def special_attributes(self):
         instance = objectmodel.BUILTIN_EXCEPTIONS.get(
             qname, objectmodel.ExceptionInstanceModel
         )
-        return instance()
+        return instance()(self)
 
 
 class DictInstance(bases.Instance):

astroid/tests/unittest_object_model.py

@@ -629,6 +629,20 @@ def test_import_error(self):
             assert isinstance(inferred, astroid.Const)
             assert inferred.value == ""
 
+    def test_exception_instance_correctly_instantiated(self):
+        ast_node = builder.extract_node(
+            """
+        try:
+            raise ImportError("a")
+        except ImportError as err:
+           err #@
+        """
+        )
+        inferred = next(ast_node.infer())
+        assert isinstance(inferred, astroid.Instance)
+        cls = next(inferred.igetattr("__class__"))
+        assert isinstance(cls, astroid.ClassDef)
+
 
 class DictObjectModelTest(unittest.TestCase):
     def test__class__(self):