Steps to reproduce:

1. Open attached project "948223.zip"
2. Open "Sample" scene
3. Open "Test" script with Visual Studio 2017
4. Insert a breakpoint in line #11
5. Attach debugger to Unity
6. Enter play mode
7. In VS17 hover over 'i32' in the breakpoint line
8. If editor hasn't crashed yet, try to expand 'i32' values

Actual behavior: Editor crashes

Reproducible with: 5.6.3p3, 2017.1.1p2, 2017.2.0f1, 2017.3.0a7

0x00007FFF58D2809F (mono-2.0-bdwgc) [c:\buildslave\mono\build\mono\mini\debugger-agent.c:6178] buffer_add_value_full
0x00007FFF58D324A2 (mono-2.0-bdwgc) [c:\buildslave\mono\build\mono\mini\debugger-agent.c:9781] object_commands
0x00007FFF58D2A29B (mono-2.0-bdwgc) [c:\buildslave\mono\build\mono\mini\debugger-agent.c:10296] debugger_thread
0x00007FFF58D82F58 (mono-2.0-bdwgc) [c:\buildslave\mono\build\mono\utils\mono-threads.c:1172] inner_start_thread
0x00007FFF8EB51FE4 (KERNEL32) BaseThreadInitThunk
0x00007FFF90FA1EB1 (ntdll) RtlUserThreadStart