https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98233
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- I don't think this is a bug. The assignment of A does a memberwise copy, which means first it assigns the A::a member, then it assigns the A::m member. That means x.m[0] = x is equivalent to: x.m[0].a = x.a; x.m[0].m = x.m; Initially x.m[0] is {9,{}}. After the first member gets assigned it is {13,{}}. After the second member gets assigned it is {13,{13,{}}}.