/* An example to show that an abstract function can be simplified to a
   concrete number. */
$abstract int foo(int x);

int main() {
  int x = foo(1);
  int a[3] = {1, 2, 3};

  $assume(foo(1) >= 0 && foo(1) <= 2);

  int y = a[x];

  $assume(foo(1) == 2);
  $when( x == 2 ) { // force canonicalization
    $assert(a[x] == 3); // true iff x is concrete
    $assert(y == 3);
  }
}