------- Comment #6 from paolo dot carlini at oracle dot com 2009-09-02 09:48 ------- Note: probably the old behavior will be restored in 4.5 as a side effect of other changes, but this type of code plays very risky games and even if it compiles, can well lead to wrong runtime behavior. Thus I definitely suggest fixing it for portability. As I said, according to the standard in order to instantiate std::vector with Inner, Inner must be CopyConstructible, that is, among other requirements, this type of code:
Inner inner1; Inner inner2(inner1); must lead to an inner2 equivalent to inner1. However, in Inner, the second line of code above actually triggers the templatized constructor, which uses an extractor, etc, something definitely *not* guaranteed to copy inner1. Adding to Inner an Inner(Inner&) and an Inner(const Inner&) would for example fix it. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41216
