https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39970
Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> changed:
What |Removed |Added
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CC| |arthur.j.odwyer at gmail dot
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--- Comment #9 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
As of C++11, the original code is legitimate-ish:
struct blah { int member; };
constexpr blah global = {42};
template <int param=global.member>
class template_blah { };
template_blah<> x; // OK, param is 42
But:
(1) GCC still incorrectly accepts the template even when `global` is non-const.
So does MSVC. Clang correctly(?) rejects it.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96213 might be related.
(2) I don't understand Brandon's original concern around mangling operator dot.
The value of the default argument here is just "42"; we don't have to mangle
the dot at all.
An example of name-mangling the dot operator would be like
template<class T>
decltype(T().x) foo() { return 0; }
struct S { int x; };
template int foo<S>();
which GCC correctly mangles as `_Z3fooI1SEDtdtcvT__E1xEv`.
So I think the only remaining issue here is the incorrect acceptance of a
non-const default argument for `int param`, and that part MIGHT duplicate bug
#96213 which I just filed.
