>perl -MO=Concise -e"use constant BUFFER => 20; if (BUFFER() != 20) {}"
3  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 72 -e:1) v ->3
-     <0> ex-const v/4 ->3
-e syntax OK

>perl -MO=Concise -e"use constant BUFFER => 20; if (BUFFER != 20) {}"
3  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 72 -e:1) v ->3
-     <0> ex-const v/4 ->3
-e syntax OK

##</code><code>##

>perl -le"use constant FOO => 'abc'; print %{{ FOO => 'def' }};"
FOOdef

>perl -le"use constant FOO => 'abc'; print %{{ FOO() => 'def' }};"
abcdef