Ref Fields bug in VisualStudio 17.4 Preview 2

dotnet7gaで治った.cs

int i = 0;
int j = 0;
int a, b;

var t0 = new RefTuple();
(a, b) = t0;
t0.Deconstruct(out a, out b);

(a, b) = new RefTuple(ref i, ref j); // CS8347
var t1 = new RefTuple(ref i, ref j);
(a, b) = t1; // CS8352
t1.Deconstruct(out a, out b);

(a, b) = new RefTuple { A = ref i, B = ref j }; // CS8168
var t2 = new RefTuple { A = ref i, B = ref j };
(a, b) = t2; // CS8352
t2.Deconstruct(out a, out b);

(a, b) = getTuple(ref i, ref j); // CS8347
var t3 = getTuple(ref i, ref j);
(a, b) = t3; // CS8352
t3.Deconstruct(out a, out b);

static RefTuple getTuple(ref int a, ref int b) => new(ref a, ref b);

ref struct RefTuple
{
    public ref int A;
    public ref int B;

    public RefTuple(ref int a, ref int b)
    {
        A = ref a;
        B = ref b;
    }

    public void Deconstruct(scoped out int a, scoped out int b)
    {
        a = A;
        b = B;
    }
}

dotnet7rc2で治った-1.cs

using System.Diagnostics.CodeAnalysis;
using System.Runtime.CompilerServices;

var a = new Array4<int>();
a[0] = 1; // CS8168
Console.WriteLine(a[0]); // CS8168

ref struct Array4<T>
{
#pragma warning disable IDE0044, IDE0051, CS0169
    T _x0, _x1, _x2, _x3;
#pragma warning restore IDE0044, IDE0051, CS0169

    [UnscopedRef]
    public ref T this[int index] => ref Unsafe.Add(ref _x0, index);

    [UnscopedRef]
    public ref T GetPinnableReference() => ref _x0;
}

ShouldError.cs

ref var r = ref m();

static ref int m()
{
    int i = 0;
    return ref m1(ref i).Item1;
    static Ref m1(scoped ref int i) => new(ref i); // A scoped ref parameter passed to new Ref() as unscoped ref.
}

#if false
static ref int m(scoped ref int i) => ref i; // CS8166
#endif

#if false
static ref int m()
{
    int i = 0;
    return ref m1(ref i).Item1; // CS8168, CS8347
    static Ref m1(ref int i) => new(ref i);
}
#endif

ref struct Ref
{
    public ref int Item1;
    public Ref(ref int item1) => Item1 = ref item1;
}