NLL ICE: unresolved type in dtorck

rustc version:
```
rustc 1.24.0-nightly (4a7c072fa 2017-12-25)
```

This is on macOS.

Enabling NLL triggers an ICE when trying to compile EdgeDNS (`nll` branch from https://github.com/jedisct1/edgedns):

```
error: internal compiler error: unresolved type in dtorck
```

This happens at link time.