mgs = SSPTR(mgs_ix, MGS*);
mgs->mgs_sv = sv;
mgs->mgs_magical = SvMAGICAL(sv);
- mgs->mgs_readonly = SvREADONLY(sv);
+ mgs->mgs_readonly = SvREADONLY(sv) != 0;
mgs->mgs_ss_ix = PL_savestack_ix; /* points after the saved destructor */
mgs->mgs_bumped = bumped;