#nullable disable
using System;
using System.Runtime.CompilerServices;

public class C {
    
    static int M1() => DoWork1("a");
    static int M2() => DoWork2("a");
    
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    static int DoWork1(ReadOnlySpan<char> value)
    {
        if (value.Length == 1)
        {
            switch (value[0] | 0x20)
            {
                case 'a': return 1;
                case 'b': return 2;
                case 'c': return 4;
                case 'd': return 8;
                case 'e': return 16;
                case 'f': return 32;
            }
        }

        throw new Exception();
    }
    
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    static int DoWork2(string value)
    {
        if (value.Length == 1)
        {
            switch (value[0] | 0x20)
            {
                case 'a': return 1;
                case 'b': return 2;
                case 'c': return 4;
                case 'd': return 8;
                case 'e': return 16;
                case 'f': return 32;
            }
        }

        throw new Exception();
    }
}