The array is not exactly deleted, but the elements are reduced to empty strings:

  DB<139> sub my_uc {
               my $c = shift;
               return uc($c);
           }
 
  DB<140> my_uc()
 
  DB<141> @a = map my_uc, a..c
 => ("", "", "")
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keep in mind no argument means $c is undef!