HashSetFn.isSubset function accesses out of bound element

[zbyrn]

structure IntHashSet = HashSetFn(IntHashTable.Key)

val set1 = IntHashSet.mkFromList [1]
val set2 = IntHashSet.mkFromList [1]

val chk = IntHashSet.isSubset (set1, set2)

Running the above code snippet results in the following exception:

Standard ML of New Jersey (64-bit) v110.99.5 [built: Thu Mar 14 17:56:03 2024]
[opening subset.sml]
[autoloading]
[library $SMLNJ-LIB/Util/smlnj-lib.cm is stable]
[autoloading done]

uncaught exception Subscript [subscript out of bounds]
  raised at: ../../smlnj-lib/Util/hash-set-fn.sml:208.32-208.41

Description

The highest index in an array of length n is n - 1; however, the isSubset function uses i <= sz to test the end of the array.