[Issue 20319] cast causing illegal instruction (core dump) in compiler

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20319

--- Comment #2 from Bartek Siudeja <siudej at gmail.com> ---
Maybe a nicer way to reproduce, pointing at handling of strings:
```
    auto data = cast(const int[]) "qwer"; // not OK
    auto data2 = cast(const int[]) "qwer".dup; // OK
```

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