Hi Richard, On 7/26/07, Richard Smith <[EMAIL PROTECTED]> wrote:
About five years ago, I reported a bug about an ICE when trying to mangle expressions involving operator new. http://gcc.gnu.org/ml/gcc-patches/2002-03/msg01417.html http://gcc.gnu.org/bugzilla/show_bug.cgi?id=6057 A three line example exhibiting the ICE is: template <unsigned int> struct helper {}; template <class T> void check( helper<sizeof(new T)>* ); int main() { check<int>(0); } As I understand it, the reason that this has never been fixed is that a full fix requires either an extension/change to the ABI which presumably requires collaboration between the eight organisations that produced it. I'm wondering whether there's any prospect of this happening, and if not, whether GCC should use the vendor extension syntax (v <digit> <source-name>) to provide a fix?
This kind of thing came up that the last C++ committee meeting, as part of core issue 339: http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#339 Name mangling is part of the problem, but not all of it. There is also the issue of what happens when there is an error in the expression "new T": is it part of the Substitution Failure Is Not An Error (SFINAE) rule, meaning that the function would not enter the overload set, or does it trigger an error immediately? That's actually the more complicated issue. As for GCC... I think we realize that we do have to fix these problems. That means we'll need name mangling for all of the expressions (and will have to extend the C++ ABI for this; vendor extensions would not be useful), and we'll have to update a lot of the type-checking for expressions in the C++ front end to propagate and obey tsubst_flags_t. - Doug
