$ perl -E 'sub W { grep { say "x"; return "z" } 1; say "y" } W'
x

##</code><code>##

$ perl -E 'sub W { grep { say "x"; return "z" } 1; say "y" } say W'
x
z

##</code><code>##

$ perl -E 'sub W { grep { say "x" } 1; say "y" } W'
x
y