[Issue 21565] @safe code allows modification of a scalar that overlaps with a pointer

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21565

--- Comment #16 from Paul Backus <snarwin+bugzilla at gmail.com> ---
(In reply to Steven Schveighoffer from comment #15)
> 
> The whole point of @safe is to avoid code review. Otherwise it's a
> glamorized linter. If you have to review @safe code to make sure things
> outside the safe code are actually memory safe, then you have lost the
> battle.

I think this is probably the root of this misunderstanding. There is nothing in
the spec (or the implementation) that *requires* you to limit your review to
@trusted code. If your proof of memory safety is based on manual review of
@safe code, then as far as the language is concerned, that's a perfectly valid
proof.

I agree completely that D should make it *possible* for the programmer to limit
their checking to @trusted code (see: DIP 1035), and that @trusted code that
relies on manual review of @safe code should be subject to close scrutiny. But
I think it would be a step too far for the language spec to outright *forbid*
anything that requires any manual review of @safe code--especially since there
is no practical way the compiler could enforce such a restriction.

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