[Issue 17448] Move semantics cause memory corruption and cryptic bugs

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17448

--- Comment #9 from Shachar Shemesh <shachar at weka.io> ---
There are two issues here. The first is that @safe does not warn about unsafe
behavior. Interesting, but unrelated to the Weka use case.

The more interesting problem here is that certain types of programming are
impossible in D. I was unable to find the statement in the most recent language
specs, but the phrasing I remember from "The D Programming Language" was along
the lines of "Structs in D may not store references to themselves, and therefor
D may move them around memory at will".

Except that is not true. First, the order is reverse. D moves them around, and
that's why they may not store references to themselves. More to the point,
however, the requirement should be made much more stringent:

D structs may not manage, directly or indirectly, any reference to themselves,
either internally as a member, or externally.

Like I stated above, that's a fairly big restriction. At the very least, the
training material should be updated to reflect it correctly, possibly also the
specs.

As things currently stand, there is no way to write a struct the manages its
own registration in an outside container without using dynamic memory (which is
never mentioned in the specs as an exception to that rule).

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