Struct should be invalid after move

John Colvin john.loughran.colvin at gmail.com
Tue Nov 27 09:50:25 UTC 2018


On Tuesday, 27 November 2018 at 08:00:22 UTC, Sebastiaan Koppe 
wrote:
> I have a non-copyable struct and I really want a compiler error 
> whenever I access it after it has been moved.
>
> ---
> struct Handle {
>     ...
>     @disable this(this);
>     ...
> }
>
> void main() {
>     import std.algorithm : move;
>     auto handle = getOne();
>     auto second = handle.move;  /// line 14
>     auto third = handle.move;    ///  <- compiler error, 
> variable handle is invalid after line 14
> }
> ---
>
> I believe this would prevent some nasty bugs when dealing with 
> these structs.
>
> What do you think?

void foo(int a)
{
     import std.algorithm : move;
     auto handle = getOne();
     if (a > 0)
         auto second = handle.move;
     auto third = handle.move; // compile error?
}

Not a trivial problem in the general case.


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