using System;
using System.Runtime.CompilerServices;
public class C
{
    public void M1(int i) => Use([i]);
    public void M2(int i) => Use(new ReadOnlySpan<int>(in i));
    
    [MethodImpl(MethodImplOptions.NoInlining)]
    private static void Use<T>(ReadOnlySpan<T> span){}
}

    public void M1(int i)
    {
        <>y__InlineArray1<int> buffer = default(<>y__InlineArray1<int>);
        <PrivateImplementationDetails>.InlineArrayElementRef<<>y__InlineArray1<int>, int>(ref buffer, 0) = i;
        Use(<PrivateImplementationDetails>.InlineArrayAsReadOnlySpan<<>y__InlineArray1<int>, int>(ref buffer, 1));
    }

    public void M2(int i)
    {
        Use(new ReadOnlySpan<int>(ref i));
    }