Fix false positive unreachable with Any in equality comparison

mypy/checker.py

@@ -7072,6 +7072,10 @@ def refine_away_none_in_comparison(
         non_optional_types = []
         for i in chain_indices:
             typ = operand_types[i]
+            # Skip Any types - they could be None, so comparing with them
+            # shouldn't narrow away None from other operands.
+            if isinstance(get_proper_type(typ), AnyType):
+                continue
             if not is_overlapping_none(typ):
                 non_optional_types.append(typ)
 

test-data/unit/check-unreachable-code.test

@@ -1650,3 +1650,15 @@ def x() -> None:
 main:4: error: Statement is unreachable
         if 5:
         ^~~~~
+
+[case testNoFalseUnreachableWithAnyEqualityNarrowing]
+# flags: --warn-unreachable
+# Regression test for https://github.com/python/mypy/issues/20532
+from typing import Any, Optional
+
+def main(contents: Any, commit: Optional[str]) -> None:
+    if (
+        contents.get("commit") == commit
+        and (commit is not None or 1)
+    ):
+        pass