eval? command does not evaluate correctly the expression

[roc007]

zshdb<0>l
  1:    #!/bin/zsh -f
  2:
  3: => if test -z "$a" ; then
  4:        echo "a is not set"
  5:    else
  6:        echo "a is set to $a"
  7:    fi
zshdb<0> ev?
eval: test -z "$a"
$? is 0
zshdb<0> ev a=22
$? is 0
zshdb<0> ev?
eval: test -z "$a"
$? is 0                # should be 1
zshdb<0>

[rocky]

@roc007 Are you up for putting in a PR for this?

[roc007]

PR done

[rocky]

Thanks!