False warning: pattern matching on a field doesn't count as a use

[alrz]

class C
{
    C field1 = null;
    public static void Main()
    {        
        _ = new C() is { field1: {} }; // CS0414 (not expected)
    }
}

class C
{
    C field1;
    public static void Main()
    {        
        _ = new C() is { field1: {} }; // CS0169 (not expected)
    }
}

Test plan: #52468

[Youssef1313]

I expect there is one or more NoteRead calls are missing in

roslyn/src/Compilers/CSharp/Portable/FlowAnalysis/DefiniteAssignment.cs

Line 1591 in 6a28cdc

private void AssignPatternVariables(BoundPattern pattern, bool definitely = true)

[jcouv]

Thanks for finding this. I'm fixing it as part of the extended property patterns.

[jcouv]

Fixed by #53594 in feature branch (planned to merge for 17.0)