Fix bug caused by bad ParameterizedClass hashing.

rchen152 · rchen152 · commit 0fd504ca7694 · 2024-01-23T14:11:08.000-08:00
Set comparisons use hashes, and ParameterizedClass.__hash__ produces different
results depending on whether its type parameters have been evaluated. We really
need to fix this, but in the meantime, this tweak to matcher.py works around
the problem.

PiperOrigin-RevId: 600620172
diff --git a/pytype/matcher.py b/pytype/matcher.py
@@ -474,7 +474,7 @@ def _match_type_param_against_type_param(self, t1, t2, subst, view):
       # constraints even if t1 is bounded.
       if not t1.constraints:
         return None  # t1 is unconstrained, t2 has constraints
-      if set(t1.constraints) - set(t2.constraints):
+      if any(c not in t2.constraints for c in t1.constraints):
         return None  # t1 is more permissive than t2
     elif t2.bound:
       if t1.bound:
