Fix crash in super-init-not-called checker

ChangeLog

@@ -45,6 +45,11 @@ Release date: TBA
 
   Closes #6028
 
+* Fix crash in ``super-init-not-called`` checker when using ``ctypes.Union``.
+
+  Closes #6027
+
+
 * Fix crash for ``unneccessary-ellipsis`` checker when an ellipsis is used inside of a container or a lambda expression.
 
   Closes #6036

pylint/checkers/classes/class_checker.py

@@ -1999,11 +1999,12 @@ def _check_init(self, node: nodes.FunctionDef, klass_node: nodes.ClassDef) -> No
 
             # Return if any of the klass' first-order bases is protocol
             for base in klass.bases:
-                # We don't need to catch InferenceError here as _ancestors_to_call
-                # already does this for us.
-                for inf_base in base.infer():
-                    if inf_base.qname() in utils.TYPING_PROTOCOLS:
-                        return
+                try:
+                    for inf_base in base.infer():
+                        if inf_base.qname() in utils.TYPING_PROTOCOLS:
+                            return
+                except astroid.InferenceError:
+                    continue
 
             if decorated_with(node, ["typing.overload"]):
                 continue

tests/functional/s/super/super_init_not_called.py

@@ -48,3 +48,10 @@ def __init__(self):
 class ChildThree(ParentWithoutInit):
     def __init__(self):  # [super-init-not-called]
         ...
+
+
+# Regression test as reported in
+# https://github.com/PyCQA/pylint/issues/6027
+class MyUnion(ctypes.Union):
+    def __init__(self):  # [super-init-not-called]
+        pass

tests/functional/s/super/super_init_not_called.txt

@@ -1,2 +1,3 @@
 undefined-variable:18:23:18:40:UninferableChild:Undefined variable 'UninferableParent':UNDEFINED
 super-init-not-called:49:4:49:16:ChildThree.__init__:__init__ method from base class 'ParentWithoutInit' is not called:INFERENCE
+super-init-not-called:56:4:56:16:MyUnion.__init__:__init__ method from base class 'Union' is not called:INFERENCE