Review the IL generated for the conversions in NativeIntegerTests.Conversions():

• The conversions to/from void* use System.[U]IntPtr.op_Explicit(void*) rather than conv.i or conv.u.
• The unchecked and checked conversions of long and ulong differ (for instance, converting nint to ulong uses conv.i8 when unchecked but conv.ovf.u8 when checked).