needed to satisfy precondition:
requires maxSet(str @ constannot.c:11:3) >= 20
constannot.c: (in function foo3)
-constannot.c:20:3: Possible out-of-bounds store:
+constannot.c:20:3: Likely out-of-bounds store:
foo(buf)
Unable to resolve constraint:
requires <const int=20> <= 19