[Bug c++/61105] New: [constexpr] accepts-invalid with new-expression in constant expression

[richard-gccbugzilla at metafoo dot co.uk]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61105

            Bug ID: 61105
           Summary: [constexpr] accepts-invalid with new-expression in
                    constant expression
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: richard-gccbugzilla at metafoo dot co.uk

G++ accepts this ill-formed code:

using size_t = decltype(sizeof(0));
constexpr void *operator new(size_t, int*) noexcept { return nullptr; }
constexpr int *p = new (nullptr) int;

This is invalid because a constant expression cannot contain an (evaluated)
new-expression.