diff --git a/mps/code/policy.c b/mps/code/policy.c
index ad4876747a9..64611a31d11 100644
--- a/mps/code/policy.c
+++ b/mps/code/policy.c
@@ -40,7 +40,7 @@ Res PolicyAlloc(Tract *tractReturn, Arena arena, LocusPref pref,
   AVERT(Arena, arena);
   AVERT(LocusPref, pref);
   AVER(size > (Size)0);
-  AVER(SizeIsAligned(size, ArenaGrainSize(arena)));
+  AVER(SizeIsArenaGrains(size, arena));
   AVERT(Pool, pool);
   AVER(arena == PoolArena(pool));