Invalid GetGenericParamInstance with extension

[disarray2077]

This is another crash I found in the LuaTinker project.

To reproduce:

1. Open the file "LuaTinker/Wrappers/Pointer/ClassInstanceWrapper.bf"
2. Add the following line at the top:

   using LuaTinker.StackHelpers;

3. At the end of the file, inside the extension ClassInstanceWrapper<T>, add:

   public void Test(LuaTinker lua)  
   {  
       StackHelper.Pop!<int>(lua, 0);  
   }  

4. The IDE should crash with the following error:

---------------------------
FATAL ERROR
---------------------------
FATAL MODULE ERROR
Invalid GetGenericParamInstance with extension at C:\Jenkins\workspace\Beef\IDEHelper\Compiler\BfModuleTypeUtils.cpp:9643
Module: 
Type: LuaTinker.Wrappers.ClassInstanceWrapper<T>
Method: LuaTinker.Wrappers.ClassInstanceWrapper<T>.Test(LuaTinker.LuaTinker lua)

Tested with: 439ae8d

[kallisto56]

Trimmed version: bug.2118trimmed3.zip
In order to trigger a crash, uncomment code inside ClassInstanceWrapper<T>.
Note: crash only happens when mixins are defined in extension and when ClassInstanceWrapper<T> has at least empty extension.

[kallisto56]

Boiled it down even further:

namespace bug2118trimmed4;

using System;

// Uncomment this to trigger a crash
//extension Foo<T> {}

class Foo<T> where T : class
{
	static void Test ()
	{
		Helper.Pop!<int>();
	}
}


class Helper {}
extension Helper
{
	static public mixin Pop<T> ()
	{
		Pop<int>()
	}

	static public T Pop<T> () where T : var, struct, INumeric
	{
		return default;
	}
}

[bfiete]

Fixed at 2f7616c