I think your version is butchering array references, and it doesn't handle scalar references. I think this works:

sub mychomp {
  while (@_) {
    for (shift) {
      ref or (eval { chomp if defined }, last);
      ref eq 'SCALAR' and (eval { chomp $$_ if defined $$_ }, last);
      ref eq 'ARRAY'  and (do { push @_, map \$_, @$_ },  last);
      ref eq 'HASH'   and (do { push @_, map \$_, values %$_ }, last);
    }
  }
}
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Question, though, why are we eval'ing the scalar chomps? chomp warns on undef, but does it fail under some condition? (update: I think I answered my own question...its for constant values which can't be chomped).