Generated WaitForDebugEvent method does not generate union correctly

[ipazanin]

Actual behavior

Default Implementation

When I import WaitForDebugEvent method, it throws System.TypeLoadException when invoked with message "Could not load type '_u_e__Union' from assembly 'Win32Bug, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' because it contains an object field at offset 0 that is incorrectly aligned or overlapped by a non-object field."

Don't Allow Marshaling workaround:

{
  "$schema": "https://aka.ms/CsWin32.schema.json",
  "allowMarshaling": false
}

From issue: Generated PROPVARIANT type is invalid #292
Results in:

var result = PInvoke.WaitForDebugEvent(out var debugEvent, 1000);
var lastError = Marshal.GetLastWin32Error();
Console.WriteLine($"result: {result}, lastError: {lastError}"); // result: 0, lastError: 6
// ERROR_INVALID_HANDLE 6 (0x6)

Expected behavior

WaitForDebugEvent method should not throw exception when invoked.

Repro steps

1. NativeMethods.txt content:

WaitForDebugEvent

2. NativeMethods.json content (if present):

{
    "$schema": "https://aka.ms/CsWin32.schema.json",
}

3. Any of your own code that should be shared?

public static void Main(string[] _)
{
    var result = PInvoke.WaitForDebugEvent(out var debugEvent, 1000);
}

Context

• CsWin32 version: 0.1.588-beta
• Win32Metadata version: not set
• Target Framework: net5.0-windows
• LangVersion: 9.0

[AArnott]

There is something about the struct (or the structs it references, actually) where at least one of them becomes "managed" in .NET terms. It's difficult to know which one it is without tedious removal of fields until it starts working. It's clearly something we need to fix. I can't give you a timeline right now.

[AArnott]

Duplicate of #292