`__rvalue` does not interact well with other constructs

[limepoutine]

This is no news, but IMO the fix of #22297 will depend on how structs in static arrays are specified to behave. There is no such specification ATM.

Postblits do work however.

struct S
{
    int i;
    this(int i) { this.i = i; }
    this(ref S s) { s.i = i; }
    this(S s) { s.i = 0; }
    ~this() { i = 0; }
}

struct T
{
    S s;
    // Uncomment to make line 33 pass
    // this(S s) { this.s = s; }
    static T make(S s) => T(s);
}

ref S move(ref S s) __rvalue => s;
T f(ref S s) => T.make(move(s));
T g(ref S s) => T(move(s));
S[1] h(ref S s) => [move(s)];

void main()
{
    // Works if a function call takes S by value
    S s1 = S(1);
    f(s1);
    assert(s1.i == 0);

    // Does not work with a struct literal, unless line 14 is uncommented
    S s2 = S(1);
    g(s2);
    assert(s2.i == 0);

    // Nor with a static array
    S s3 = S(1);
    h(s3);
    assert(s3.i == 0);
}