Target-typed new can be passed in implicit-typed array

[KyouyamaKazusa0805]

Consider the code in C# 9:

public class C
{
    public void M()
    {
        A[] z1 = new[] { new() }; // CS0826.
        var z2 = new[] { new A() };
        var z3 = new A[] { new() };
        var z4 = new A[] { new A() };
    }
}

public readonly struct A
{
    public readonly int Prop => 3;
}

I think that all four cases should be okay, but in fact, Roslyn throws a syntax error CS0826 (No best type found for implicitly-typed array) for the new expression of z1 . The reason why I think z1 is okay is that A is a struct, so new[] means new A[] as the only possibility. Therefore, the inner expression new() should stand for new A().

[CyrusNajmabadi]

We could consider target-typing implicit arrays as a fallback if the type of it cannot be determined based on its elements.

[333fred]

Duplicate of #2701. I'm going to close this out.