ref struct and return ref this.

[lieene]

ref struct is supposed to live only on stack and unmanaged.
in a struct like

ref struct CanReturnRef
{
    public CanReturnRef( int i ) => this.i=i;
    private int i;
    public int Value=> i;
    public ref CanReturnRef Next()
    {
        i++;
        return ref this;
    }
}

return ref this; Should be allowed.
So a Fluent design will work better;
for example

{
    Print( new CanReturnRef(0).Next().Next().Next().Value );//output 3
    var fluent = new CanReturnRef(0);
    fluent.Next().Next().Next();
    Print(fluent.Value);//output 1 which is not expected, but can be fixed by return ref this.
}

[canton7]

See also: #1997

[lieene]

#1997 is for general struct where the case is much more complicated.
A ref struct can not be used as a field of any managed type.
So return ref this does not involve any GC pin problem. It's simple and valid.

[svick]

There is already a proposal that will allow you to do this. As far as I can tell, the championed issue for that is #1147.