perl -e '$a = \"constant"; bless($a, "Test");'
Modification of a read-only value attempted at -e line 1.

##</code><code>##

perl -MBit::Vector -e '$a = new Bit::Vector(8); ${$a} = 2;'
Modification of a read-only value attempted at -e line 1.

##</code><code>##

reference = sv_bless(sv_2mortal(newRV(handle)),  BitVector_Stash);

##</code><code>##

reference = sv_bless(sv_2mortal(newRV(handle)), gv_stashpv(SvPV_nolen(class), 1));