Boolean Marshalling with LayoutKind.Explicit, Is this broken or failing as designed?

Question

First of all the Boolean type is said to have a default marshal type of a four-byte value. So the following code works:

    struct A 
    { 
        public          


        

Answer 1

The line commented with 'FAILS, WOW, WTF?' fails because of the way boolean comparison is performed. It is comparing 2 to 1:

IL_007e:  ldc.i4.1
IL_007f:  ldloca.s 3
IL_0081:  ldflda valuetype Test/A Test/Broken::a
IL_0086:  ldfld bool Test/A::bValue1
IL_008b:  ceq

ceq ends up comparing 1 to the byte in bValue, which is 2.

The funny thing is that if (broken.a.bValue1) will test 'true' because it's non-zero.

As far as the other problem (broken.a.iValue2 == 4), it went away when I applied:

[MarshalAs (UnmanagedType.Bool)]

to both boolean fields in the structures. This makes sure the booleans are marshaled as an integer (4 bytes in .NET).