http://www.perlmonks.org?node_id=946495


in reply to Re: ref to read-only alias ... why?
in thread ref to read-only alias ... why?

In your case, $_ is an alias for the constant 1, not an lvalue, so can't be assigned to.

This doesn't really answer the OP's question why it does not fail when you try to modify the constant via a reference to the alias.