Re: Test for C++20 p0858 - ConstexprIterator requirements.

["Ed Smith-Rowland via libstdc++" <libstdc++ at gcc dot gnu dot org>]

On 6/1/19 2:42 PM, Ville Voutilainen wrote:
> On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland <3dw4rd@verizon.net> wrote:
> > On 5/31/19 6:29 PM, Ville Voutilainen wrote:
> > > On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++
> > > <libstdc++@gcc.gnu.org> wrote:
> > > > Greetings,
> > > >
> > > > Iterators for <array> and <string_view> are usabe in a constexpr context
> > > > since C++2017.
> > > >
> > > > This just adds a compile test to make sure and check a box for C++20
> > > > p0858 - ConstexprIterator requirements.
> > > Those tests don't use the iterators in a constexpr context. To do
> > > that, maybe do those std::copy operations
> > > in a constexpr function and then initialize a constexpr variable with
> > > the result of a call to that function?
> > Thanks Ville,
> >
> > I had completely forgotten to make these test functions constexpr - FIXED.
> .but that doesn't enforce a constexpr context. If you add another
> function that calls these functions
> and initializes a constexpr variable, then we have the enforcement I
> seek. Such as
>
> void test2()
> {
>      constexpr char x = test();
> }
Ok, third time's a charm.

I was brain dead about the constexpr patch.?? I'm now setting a constexpr 
variable from test() in a caller.

But static_assert is a constexpr context no?

Ed

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