[Backport maintenance/3.3.x] Consistency between is/is not and ==/!= when comparing types for unidiomatic-typecheck (#10170)

doc/whatsnew/fragments/10161.false_positive

@@ -0,0 +1,3 @@
+Comparisons between two calls to `type()` won't raise an ``unidiomatic-typecheck`` warning anymore, consistent with the behavior applied only for ``==`` previously.
+
+Closes #10161

pylint/checkers/base/comparison_checker.py

@@ -323,14 +323,10 @@ def _check_unidiomatic_typecheck(self, node: nodes.Compare) -> None:
         if operator in TYPECHECK_COMPARISON_OPERATORS:
             left = node.left
             if _is_one_arg_pos_call(left):
-                self._check_type_x_is_y(node, left, operator, right)
+                self._check_type_x_is_y(node=node, left=left, right=right)
 
     def _check_type_x_is_y(
-        self,
-        node: nodes.Compare,
-        left: nodes.NodeNG,
-        operator: str,
-        right: nodes.NodeNG,
+        self, node: nodes.Compare, left: nodes.NodeNG, right: nodes.NodeNG
     ) -> None:
         """Check for expressions like type(x) == Y."""
         left_func = utils.safe_infer(left.func)
@@ -339,7 +335,7 @@ def _check_type_x_is_y(
         ):
             return
 
-        if operator in {"is", "is not"} and _is_one_arg_pos_call(right):
+        if _is_one_arg_pos_call(right):
             right_func = utils.safe_infer(right.func)
             if (
                 isinstance(right_func, nodes.ClassDef)

tests/functional/u/unidiomatic_typecheck.py

@@ -57,14 +57,28 @@ def parameter_shadowing_inference_negatives(type):
     type(42) in [int]
     type(42) not in [int]
 
-def deliberate_subclass_check_negatives(b):
+
+def deliberate_subclass_check_negatives(a, b):
     type(42) is type(b)
     type(42) is not type(b)
+    type(42) == type(b)
+    type(42) != type(b)
+    type(a) is type(b)
+    type(a) is not type(b)
+    type(a) == type(b)
+    type(a) != type(b)
+
 
 def type_of_literals_positives(a):
-    type(a) is type([]) # [unidiomatic-typecheck]
-    type(a) is not type([]) # [unidiomatic-typecheck]
-    type(a) is type({}) # [unidiomatic-typecheck]
-    type(a) is not type({}) # [unidiomatic-typecheck]
-    type(a) is type("") # [unidiomatic-typecheck]
-    type(a) is not type("") # [unidiomatic-typecheck]
+    type(a) is type([])  # [unidiomatic-typecheck]
+    type(a) is not type([])  # [unidiomatic-typecheck]
+    type(a) is type({})  # [unidiomatic-typecheck]
+    type(a) is not type({})  # [unidiomatic-typecheck]
+    type(a) is type("")  # [unidiomatic-typecheck]
+    type(a) is not type("")  # [unidiomatic-typecheck]
+    type(a) == type([])  # [unidiomatic-typecheck]
+    type(a) != type([])  # [unidiomatic-typecheck]
+    type(a) == type({})  # [unidiomatic-typecheck]
+    type(a) != type({})  # [unidiomatic-typecheck]
+    type(a) == type("")  # [unidiomatic-typecheck]
+    type(a) != type("")  # [unidiomatic-typecheck]

tests/functional/u/unidiomatic_typecheck.txt

@@ -6,9 +6,15 @@ unidiomatic-typecheck:12:4:12:20:simple_inference_positives:Use isinstance() rat
 unidiomatic-typecheck:13:4:13:24:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
 unidiomatic-typecheck:14:4:14:20:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
 unidiomatic-typecheck:15:4:15:20:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
-unidiomatic-typecheck:65:4:65:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
-unidiomatic-typecheck:66:4:66:27:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
-unidiomatic-typecheck:67:4:67:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
-unidiomatic-typecheck:68:4:68:27:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
-unidiomatic-typecheck:69:4:69:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
-unidiomatic-typecheck:70:4:70:27:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:73:4:73:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:74:4:74:27:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:75:4:75:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:76:4:76:27:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:77:4:77:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:78:4:78:27:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:79:4:79:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:80:4:80:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:81:4:81:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:82:4:82:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:83:4:83:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
+unidiomatic-typecheck:84:4:84:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED