Fix used-before-assignment for functions/classes defined in type checking guard

Close #7368

Author: Rogdham

doc/whatsnew/fragments/7368.false_positive

@@ -0,0 +1,3 @@
+Fix ``used-before-assignment`` for functions/classes defined in type checking guard.
+
+Closes #7368

pylint/checkers/variables.py

@@ -1841,7 +1841,6 @@ def _is_variable_violation(
         base_scope_type,
         is_recursive_klass,
     ) -> tuple[bool, bool, bool]:
-        # pylint: disable=too-many-nested-blocks
         maybe_before_assign = True
         annotation_return = False
         use_outer_definition = False
@@ -2014,8 +2013,13 @@ def _is_variable_violation(
                                 for target in definition.targets
                                 if isinstance(target, nodes.AssignName)
                             )
-                            if defined_in_or_else:
-                                break
+                        elif isinstance(
+                            definition, (nodes.ClassDef, nodes.FunctionDef)
+                        ):
+                            defined_in_or_else = definition.name == node.name
+
+                        if defined_in_or_else:
+                            break
 
                     if not used_in_branch and not defined_in_or_else:
                         maybe_before_assign = True

tests/functional/u/undefined/undefined_variable.py

@@ -267,15 +267,24 @@ def func_should_fail(_dt: datetime):  # [used-before-assignment]
 if TYPE_CHECKING:
     from collections import Counter
     from collections import OrderedDict
+    from collections import defaultdict
+    from collections import UserDict
 else:
     Counter = object
     OrderedDict = object
+    def defaultdict():
+        return {}
+    class UserDict(dict):
+        pass
 
 
 def tick(counter: Counter, name: str, dictionary: OrderedDict) -> OrderedDict:
     counter[name] += 1
     return dictionary
 
+defaultdict()
+
+UserDict()
 
 # pylint: disable=unused-argument
 def not_using_loop_variable_accordingly(iterator):

tests/functional/u/undefined/undefined_variable.txt

@@ -28,12 +28,12 @@ undefined-variable:171:4:171:13::Undefined variable 'unicode_3':UNDEFINED
 undefined-variable:226:25:226:37:LambdaClass4.<lambda>:Undefined variable 'LambdaClass4':UNDEFINED
 undefined-variable:234:25:234:37:LambdaClass5.<lambda>:Undefined variable 'LambdaClass5':UNDEFINED
 used-before-assignment:255:26:255:34:func_should_fail:Using variable 'datetime' before assignment:HIGH
-undefined-variable:282:18:282:24:not_using_loop_variable_accordingly:Undefined variable 'iteree':UNDEFINED
-undefined-variable:299:27:299:28:undefined_annotation:Undefined variable 'x':UNDEFINED
-used-before-assignment:300:7:300:8:undefined_annotation:Using variable 'x' before assignment:HIGH
-undefined-variable:330:11:330:12:decorated3:Undefined variable 'x':UNDEFINED
-undefined-variable:335:19:335:20:decorated4:Undefined variable 'y':UNDEFINED
-undefined-variable:356:10:356:20:global_var_mixed_assignment:Undefined variable 'GLOBAL_VAR':HIGH
-undefined-variable:368:19:368:44:RepeatedReturnAnnotations.x:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
-undefined-variable:370:19:370:44:RepeatedReturnAnnotations.y:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
-undefined-variable:372:19:372:44:RepeatedReturnAnnotations.z:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
+undefined-variable:291:18:291:24:not_using_loop_variable_accordingly:Undefined variable 'iteree':UNDEFINED
+undefined-variable:308:27:308:28:undefined_annotation:Undefined variable 'x':UNDEFINED
+used-before-assignment:309:7:309:8:undefined_annotation:Using variable 'x' before assignment:HIGH
+undefined-variable:339:11:339:12:decorated3:Undefined variable 'x':UNDEFINED
+undefined-variable:344:19:344:20:decorated4:Undefined variable 'y':UNDEFINED
+undefined-variable:365:10:365:20:global_var_mixed_assignment:Undefined variable 'GLOBAL_VAR':HIGH
+undefined-variable:377:19:377:44:RepeatedReturnAnnotations.x:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
+undefined-variable:379:19:379:44:RepeatedReturnAnnotations.y:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
+undefined-variable:381:19:381:44:RepeatedReturnAnnotations.z:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED