https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85087
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |INVALID --- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Martin Sebor from comment #0) > While looking at bug 85043 I noticed that in the test case below, GCC > correctly rejects the attempt to convert the const reference to B to A in > the call to g() No, it allows the conversion, but that produces an rvalue which can't bind to the A& parameter of g. > but it accepts the same invalid conversion in the context > where a a non-const member function on the result of the conversion is > called. Other compilers reject both conversions. Why should it be rejected? ((A)b) calls the conversion operator to get a const A& and then initializes an rvalue of type A from that. The rvalue is not const, and you can call the member function. i.e. equivalent to: static_cast<A>(b.operator const A&()).f(); or: A(b).f(); both of which are accepted, as they should be. EDG accepts the static_cast<A> version, but not A(b).f(), I don't know why. But I think EDG has the bug here, not GCC.