[Issue 20956] [DIP1000] @safe defeated by closure capturing ref parameter

Jun 19, 2020

Mathias LANG

Jan 04, 2022

Dennis

Aug 12, 2022

Walter Bright

Aug 12, 2022

Dlang Bot

Dec 17, 2022

Iain Buclaw

https://issues.dlang.org/show_bug.cgi?id=20956 Mathias LANG <pro.mathias.lang@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |industry --

January 04, 2022

[Issue 20956] [DIP1000] @safe defeated by closure capturing ref parameter

Posted by Dennis

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Dennis

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https://issues.dlang.org/show_bug.cgi?id=20956

Dennis <dkorpel@live.nl> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dkorpel@live.nl

--- Comment #1 from Dennis <dkorpel@live.nl> ---
Reduced a bit more:
```
@safe:
alias DG = void delegate() @safe;

void main()
{
    DG dg = getDg(42);
    stompStack();
    dg();
}

DG getDg(int val)
{
    return forwardDg(val);
}

DG forwardDg(ref int c)
{
    return () {assert(c == 42);};
}

void stompStack()
{
    int[256] oops = int.max;
}
```
Also, it fails both with or without -dip1000. I think closing over a ref
parameter should be an error (at least in `@safe` code), because it's really
hard for `forwardDg` to create a closure including the stack frame of `getDg`:
it has to be done at runtime, since you can't statically know where the `ref`
parameter came from.

--

https://issues.dlang.org/show_bug.cgi?id=20956 Walter Bright <bugzilla@digitalmars.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bugzilla@digitalmars.com See Also| |https://issues.dlang.org/sh | |ow_bug.cgi?id=8538 --

https://issues.dlang.org/show_bug.cgi?id=20956 Dlang Bot <dlang-bot@dlang.rocks> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |pull --- Comment #2 from Dlang Bot <dlang-bot@dlang.rocks> --- @WalterBright updated dlang/dmd pull request #14364 "fix Issue 20956 - [DIP1000] @safe defeated by closure capturing ref p…" fixing this issue: - fix Issue 20956 - [DIP1000] @safe defeated by closure capturing ref parameter https://github.com/dlang/dmd/pull/14364 --

https://issues.dlang.org/show_bug.cgi?id=20956 Iain Buclaw <ibuclaw@gdcproject.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Priority|P1 |P2 --

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