(bugfix) Issue 10161: Incorrect scenario of unidiomatic-typecheck.

Author: Nedelcu

doc/whatsnew/fragments/10161.false_positive

@@ -0,0 +1,3 @@
+Fix a false positive for `unidiomatic-typecheck` when comparing two direct types.
+
+Closes #10161

pylint/checkers/base/comparison_checker.py

@@ -343,15 +343,12 @@ def _check_type_x_is_y(
         ):
             return
 
-        if operator in {"is", "is not"} and _is_one_arg_pos_call(right):
+        if operator in {"!=", "==", "is", "is not"} and _is_one_arg_pos_call(right):
             right_func = utils.safe_infer(right.func)
             if (
                 isinstance(right_func, nodes.ClassDef)
                 and right_func.qname() == TYPE_QNAME
             ):
                 # type(x) == type(a)
-                right_arg = utils.safe_infer(right.args[0])
-                if not isinstance(right_arg, LITERAL_NODE_TYPES):
-                    # not e.g. type(x) == type([])
-                    return
+                return
         self.add_message("unidiomatic-typecheck", node=node)

tests/functional/u/unidiomatic_typecheck.py

@@ -65,10 +65,22 @@ def deliberate_subclass_check_negatives(b):
     type(42) is type(b)
     type(42) is not 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]
+def type_of_literals_negatives(a):
+    type(a) is type([])
+    type(a) is not type([])
+    type(a) is type({})
+    type(a) is not type({})
+    type(a) is type("")
+    type(a) is not type("")
+    type(a) == type([])
+    type(a) != type([])
+    type(a) == type({})
+    type(a) != type({})
+    type(a) == type("")
+    type(a) != type("")
+
+def double_type_check_negatives(a, b):
+    type(a) == type(b)
+    type(a) != type(b)
+    type(a) is type(b)
+    type(a) is not type(b)

tests/functional/u/unidiomatic_typecheck.txt

@@ -10,9 +10,3 @@ unidiomatic-typecheck:16:4:16:20:simple_inference_positives:Use isinstance() rat
 unidiomatic-typecheck:17:4:17:24:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
 unidiomatic-typecheck:18:4:18:20:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
 unidiomatic-typecheck:19:4:19:20:simple_inference_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:71:4:71:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
-unidiomatic-typecheck:72:4:72:27: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