if (@x{1,2})

##</code><code>##

if ($x{2})

##</code><code>##

if (@{[ EXPR ]})    # Array

if (map 1, EXPR)    # map

if (grep 1, EXPR)   # grep

if (() = EXPR)      # List assignment

if (count(EXPR))    # External function such as
                    #    sub count { 0+@_ }