shell> perl -MO=Deparse -
sub m{
 local *_=\$_[0];
 s///;
}
 m("String");

sub m {
    local *_ = \$_[0];
    s///;
}
/"String"/;
- syntax OK

##</code><code>##

sub replace {
  local *_=\$_[0];
  s///;
}
replace("String");

Modification of a read-only value attempted at pmsopw_250834.pl line 3.