Re^3: Shortcut operator for $a->{'b'}=$b if $b;

[CountZero]

in reply to Re^2: Shortcut operator for $a->{'b'}=$b if $b;
in thread Shortcut operator for $a->{'b'}=$b if $b;

And thereby logical false values do not get assigned, which is not as per the specs.

[Roy Johnson]

You should re-read the OP's post. It says "The point is to have no key 'b' exist if $b is false."