Ref-assigning a ref parameter to a ref field with primary constructor

[ufcpp]

Version Used:

Visual Studio 17.6 Preview 2
C# Tools 4.6.0-2.23151.17+1314d090671dc1a1500c5303c4b5ae9150f40d98

Steps to Reproduce:

ref struct Ok
{
    public ref int Ref;

    public Ok(ref int x)
    {
        Ref = ref x; // OK
    }
}

ref struct Error(ref int x)
{
    public ref int Ref = ref x; // CS9077. Isn't this a bug?
}

ref struct ForReference([UnscopedRef] ref int x)
{
    public ref int Ref = ref x; // OK

    public void M1(ref int x)
    {
        Ref = ref x; // CS9077. This is correct.
    }

    public void M2([UnscopedRef] ref int x)
    {
        Ref = ref x; // OK
    }
}

Expected Behavior:

No error on public ref int Ref = ref x;, for consistency with Ok struct.

Actual Behavior:

CS9077 error.

See also #68610

[jcouv]

@AlekseyTs Please advise/triage

[AlekseyTs]

@jcouv It looks like ref safety for field initializers is not analyzed as ref safety for field assignments. This feels like a problem with the ref safety analysis, even if it is exposed by using primary constructors.

[jcouv]

@cston Is this a known issue for ref fields? I couldn't find an existing issue on this.

[FaustVX]

I've came across the same issue (#69055),
And I found a workaround for this if you are interrested.
It use Unsafe.AsRef() on the ref primary parameter.

ref struct Workaround(ref int x)
{
    public ref int Ref = ref Unsafe.AsRef(in x);
}

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