https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54483
Mitsuru Kariya <kariya_mitsuru at hotmail dot com> changed:
What |Removed |Added
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CC| |kariya_mitsuru at hotmail dot
com
--- Comment #9 from Mitsuru Kariya <kariya_mitsuru at hotmail dot com> ---
(In reply to Juisoo from comment #8)
> However, if I add another data member which is initialized with val by
> default, I still get the "undefined reference" error, see second attachment.
The second testcase is reduced like below.
============== testcase ==============
struct A {
static constexpr float val = 0.08;
A(const float& = val) {}
};
int main()
{
A{};
}
============== testcase ==============
cf. http://melpon.org/wandbox/permlink/ZCbNwLlPQakWjluY
I think that the testcase is ill-formed because the A::val is odr-used.
When A's ctor is called with no argument,
1) The lvalue-to-rvalue conversion is not applied to A::val.
(Since the ctor's parameter is a reference type.)
2) A::val is not a discarded-value expression.
On the other hand, A::val is not odr-used in the first testcase.
(Since the builtin unary - operator requires that its operand is a prvalue.)
So, I think that this pr is fixed.
(But I don't know whether this pr can be closed since I cannot find a test.)
