FS0193 error when specifying sequential struct layout of a type

[kasperhj]

While translating some C# code into F# I noticed some unexpected behavior with structlayout.

Having

type MyType =
    struct
        val a: int
    end

is fine, but having

open System.Runtime.InteropServices
[<type:StructLayout(LayoutKind.Sequential, Pack=1)>]
type LayoutType =
    struct
        val a: int
    end

results in an error:

error FS0193: internal error: Could not load type 'LayoutType' from assembly 'FSI-ASSEMBLY, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' because field 'a@' was not given an explicit offset.

Setting Pack=0 and everything is fine.

I tried this out in VS2013 and VS2015 CTP 6, and the results are identical.

/@kasperhj

[KevinRansom]

I can repro this too. According to : https://msdn.microsoft.com/en-us/library/vstudio/system.runtime.interopservices.structlayoutattribute.pack(v=vs.100).aspx

1 is a valid value for pack,
setting it to 1 or any other non zero that I tried for that matter results in:

error FS0193: internal error: Could not load type 'LayoutType' from assembly 'FSI-ASSEMBLY, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' because field 'a@' was not given an explicit offset.

[asik]

Yes I had noticed this a while ago: http://stackoverflow.com/questions/24587684/structlayout-limitation-in-f-interactive