[Issue 19768] Compiler segfaults with -checkaction=context

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19768

--- Comment #1 from kinke at gmx.net ---
Somewhat reduced (from https://github.com/ldc-developers/ldc/issues/3058):
```
import std.string;
```

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