m=Concise
diff <(perl -MO=$m -e 'use constant A => 12; my %hash = ( A() => "twelve")') \
     <(perl -MO=$m -e 'use constant A => 12; my %hash = ( (A) => "twelve")')

7c7
< 4           <$> const[IV 12] s*/FOLD ->5
---
> 4           <$> const[IV 12] sP*/FOLD ->5