Try to infer any variances that can be inferred

Also avoid inferring variances repeatedly.
python · May 16, 2024 · dba87a8 · dba87a8
1 parent 369a4af
commit dba87a8
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
@@ -2049,8 +2049,9 @@ def infer_class_variances(info: TypeInfo) -> bool:
     if not info.defn.type_args:
         return True
     tvs = info.defn.type_vars
+    success = True
     for i, tv in enumerate(tvs):
-        if isinstance(tv, TypeVarType):
+        if isinstance(tv, TypeVarType) and tv.variance == VARIANCE_NOT_READY:
             if not infer_variance(info, i):
-                return False
-    return True
+                success = False
+    return success