StructLayoutBug

StructLayoutBug.cs

using System;
using System.Linq;
using System.Runtime.InteropServices;

// Requires the NuGet package https://www.nuget.org/packages/ObjectLayoutInspector/
namespace StructLayoutApp
{
    [StructLayout(LayoutKind.Explicit)]
    struct ExplicitLayoutStruct {
        [FieldOffset(0)] public byte B00;
    }

    struct RegularStruct
    {
        public int Field;
    }

    struct BoolAndExplicitStruct
    {
        // bool AND a field with an explicit layout struct
        // change the layout of this struct to Auto instead of sequential
        public bool Bool;
        //public char Char; // same behavior than bool
        public ExplicitLayoutStruct ExplicitLayout;
        public int Int32;
        public RegularStruct RegularStruct;
        public long Int64;
    }

    // Field Int64: starts at offset 0
    // Field Int32: starts at offset 8
    // Field Bool: starts at offset 12
    // Field ExplicitLayout: starts at offset 16
    // Field RegularStruct: starts at offset 24

    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                Console.WriteLine(
                    string.Join("\n",
                        ObjectLayoutInspector.TypeInspector.GetFieldOffsets<BoolAndExplicitStruct>()
                            .Select(tpl => $"Field {tpl.fieldInfo.Name}: starts at offset {tpl.offset}"))
                );
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
            }
        }
    }
}