Constructor flow analysis doesn't understand noreturn

[pbackus]

As of DMD 2.109.1, the following program fails to compile:

struct MustInit
{
    int n;
    @disable this();
    this(int n) { this.n = n; }
}

struct S
{
    MustInit member;
    this(bool b, int n, int m)
    {
        if (b == true) {
            member = MustInit(n);
            return;
        }
        if (b == false) {
            member = MustInit(m);
            return;
        }
        assert(0); // unreachable
    }
}

The error message is:

bug.d(11): Error: constructor bug.S.this field member must be initialized but skipped

Since the code path that skips the initialization of member contains assert(0), and will never return, this code should be allowed to compile.

[pbackus]

See also #20054

[Herringway]

It doesn't seem to understand noreturn in general here. A throw new Exception("Whoopsie daisy"); or a call to noreturn foo(); ought to succeed as well?

[pbackus]

Yes, ideally any noreturn expression would work here, not just assert(0).