Fix used-before-assignment for conditional self-referential typing (#5532)

Author: DanielNoord

ChangeLog

@@ -25,6 +25,11 @@ Release date: TBA
 
   Closes #3793
 
+* Fixed false positive for ``used-before-assignment`` with self-referential type
+  annotation in conditional statements within class methods.
+
+  Closes #5499
+
 * ``used-before-assignment`` now assumes that assignments in except blocks
   may not have occurred and warns accordingly.
 

doc/whatsnew/2.13.rst

@@ -60,6 +60,11 @@ Other Changes
 
   Closes #3793
 
+* Fixed false positive for ``used-before-assignment`` with self-referential type
+  annotation in conditional statements within class methods.
+
+  Closes #5499
+
 * ``used-before-assignment`` now assumes that assignments in except blocks
   may not have occurred and warns accordingly.
 

pylint/checkers/variables.py

@@ -1817,7 +1817,7 @@ def _is_first_level_self_reference(
         """
         if (
             node.frame().parent == defstmt
-            and node.statement(future=True) not in node.frame().body
+            and node.statement(future=True) == node.frame()
         ):
             # Check if used as type annotation
             # Break but don't emit message if postponed evaluation is enabled

tests/functional/u/use/used_before_assignment_typing.py

@@ -61,3 +61,16 @@ def inner_method(self, other: MyOtherClass) -> bool:
     def self_referential_optional_within_method(self) -> None:
         variable: Optional[MyOtherClass] = self
         print(variable)
+
+
+class MyThirdClass:
+    """Class to test self referential variable typing within conditionals.
+    This regressed, reported in: https://github.com/PyCQA/pylint/issues/5499
+    """
+
+    def function(self, var: int) -> None:
+        if var < 0.5:
+            _x: MyThirdClass = self
+
+    def other_function(self) -> None:
+        _x: MyThirdClass = self