  $hk01 = haskey($x, $a);
  $hk02 = haskey($nonesuch, $a);
  $hk03 = haskey($*, 7);
  $hk04 = haskey($*, "a");
  $hk05 = haskey($*, "nonesuch");
  $hk06 = haskey([10,20,30], 0);
  $hk07 = haskey([10,20,30], 1);
  $hk08 = haskey([10,20,30], 2);
  $hk09 = haskey([10,20,30], 3);
  $hk10 = haskey([10,20,30], 4);
  $hk11 = haskey([10,20,30], -4);
  $hk12 = haskey([10,20,30], -3);
  $hk13 = haskey([10,20,30], -2);
  $hk14 = haskey([10,20,30], -1);
  $hk15 = haskey([10,20,30], "a");

