``unidiomatic-typecheck`` is no longer emitted for ``in`` and ``not in`` operators

The original use case for this check was to catch old style type checking idioms
such as `type(x) is ...`, but it should not have been extended to handle `in` operators
as well.

Close #3337

4 files changed, 13 insertions, 18 deletions

diff --git a/ChangeLog b/ChangeLog
index 3ed3e66da..f8d322ef6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -26,6 +26,10 @@ Release date: TBA
 
 * Positional-only arguments are taken in account for ``useless-super-delegation``
 
+* ``unidiomatic-typecheck`` is no longer emitted for ``in`` and ``not in`` operators
+
+  Close #3337
+
 * Positional-only argument annotations are taken in account for ``unused-import``
 
   Close #3462
diff --git a/pylint/checkers/base.py b/pylint/checkers/base.py
index f5117ed0e..ed22ff443 100644
--- a/pylint/checkers/base.py
+++ b/pylint/checkers/base.py
@@ -152,7 +152,7 @@ NO_REQUIRED_DOC_RGX = re.compile("^_")
 REVERSED_PROTOCOL_METHOD = "__reversed__"
 SEQUENCE_PROTOCOL_METHODS = ("__getitem__", "__len__")
 REVERSED_METHODS = (SEQUENCE_PROTOCOL_METHODS, (REVERSED_PROTOCOL_METHOD,))
-TYPECHECK_COMPARISON_OPERATORS = frozenset(("is", "is not", "==", "!=", "in", "not in"))
+TYPECHECK_COMPARISON_OPERATORS = frozenset(("is", "is not", "==", "!="))
 LITERAL_NODE_TYPES = (astroid.Const, astroid.Dict, astroid.List, astroid.Set)
 UNITTEST_CASE = "unittest.case"
 BUILTINS = builtins.__name__
diff --git a/tests/functional/u/unidiomatic_typecheck.py b/tests/functional/u/unidiomatic_typecheck.py
index 008456b1e..302bcc2b7 100644
--- a/tests/functional/u/unidiomatic_typecheck.py
+++ b/tests/functional/u/unidiomatic_typecheck.py
@@ -6,8 +6,6 @@ def simple_positives():
     type(42) is not int # [unidiomatic-typecheck]
     type(42) == int # [unidiomatic-typecheck]
     type(42) != int # [unidiomatic-typecheck]
-    type(42) in [int] # [unidiomatic-typecheck]
-    type(42) not in [int] # [unidiomatic-typecheck]
 
 def simple_inference_positives():
     alias = type
@@ -15,16 +13,12 @@ def simple_inference_positives():
     alias(42) is not int # [unidiomatic-typecheck]
     alias(42) == int # [unidiomatic-typecheck]
     alias(42) != int # [unidiomatic-typecheck]
-    alias(42) in [int] # [unidiomatic-typecheck]
-    alias(42) not in [int] # [unidiomatic-typecheck]
 
 def type_creation_negatives():
     type('Q', (object,), dict(a=1)) is int
     type('Q', (object,), dict(a=1)) is not int
     type('Q', (object,), dict(a=1)) == int
     type('Q', (object,), dict(a=1)) != int
-    type('Q', (object,), dict(a=1)) in [int]
-    type('Q', (object,), dict(a=1)) not in [int]
 
 def invalid_type_call_negatives(**kwargs):
     type(bad=7) is int
diff --git a/tests/functional/u/unidiomatic_typecheck.txt b/tests/functional/u/unidiomatic_typecheck.txt
index 23c0f6f28..65f2aa59e 100644
--- a/tests/functional/u/unidiomatic_typecheck.txt
+++ b/tests/functional/u/unidiomatic_typecheck.txt
@@ -3,16 +3,13 @@ unidiomatic-typecheck:6:simple_positives:Using type() instead of isinstance() fo
 unidiomatic-typecheck:7:simple_positives:Using type() instead of isinstance() for a typecheck.
 unidiomatic-typecheck:8:simple_positives:Using type() instead of isinstance() for a typecheck.
 unidiomatic-typecheck:9:simple_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:10:simple_positives:Using type() instead of isinstance() for a typecheck.
+unidiomatic-typecheck:12:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
+unidiomatic-typecheck:13:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
 unidiomatic-typecheck:14:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
 unidiomatic-typecheck:15:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:16:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:17:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:18:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:19:simple_inference_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:71:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:72:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:73:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:74:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:75:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
-unidiomatic-typecheck:76:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
\ No newline at end of file
+unidiomatic-typecheck:65:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
+unidiomatic-typecheck:66:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
+unidiomatic-typecheck:67:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
+unidiomatic-typecheck:68:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
+unidiomatic-typecheck:69:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.
+unidiomatic-typecheck:70:type_of_literals_positives:Using type() instead of isinstance() for a typecheck.