On Thursday, 3 October 2019 at 11:56:55 UTC, Oleg B wrote:
I think this code must get compilation error, but it didn't, furthermore result program get UB.
Indeed, the spec allows the compiler to issue an error, but doesn't require it. tbh it was due to difficulty in implementing the compile time error back when it was designed, so Walter kept the spec flexible.
If you mark the function as @safe now, you will get a compile error on it now. But without that annotation, the compiler keeps its older, looser behavior.
