• vitamin (20/20) Jan 28 2021 Is there reason why std.conv.emplace doesn't forward arguments to
• kinke (5/7) Jan 28 2021 Yeah, a bug in the emplace() version for classes, some missing
• vitamin (2/9) Jan 30 2021 thanks;
• kinke (2/12) Feb 01 2021 It's already fixed: https://github.com/dlang/druntime/pull/3352

vitamin <vit vit.vit> writes:

Is there reason why std.conv.emplace doesn't forward arguments to 
__ctor?

this doesn't work:

import std.conv : emplace;
import std.functional : forward;

struct Bar{
	
      disable this(const ref typeof(this) rhs)pure nothrow  safe 
 nogc;
}

class Foo{
     Bar bar;

     this(Bar bar){
     	this.bar = forward!bar;
     }
}

void main(){
     void[__traits(classInstanceSize, Foo)] tmp = void;

     emplace!Foo(cast(Foo)tmp.ptr, Bar.init);   //error
}

kinke <noone nowhere.com> writes:

On Thursday, 28 January 2021 at 21:15:49 UTC, vitamin wrote:
 Is there reason why std.conv.emplace doesn't forward arguments 
 to __ctor?

Yeah, a bug in the emplace() version for classes, some missing 
`forward!args` in there (it works when emplacing a struct with 
identical ctor). E.g. 
https://github.com/dlang/druntime/blob/e2e304e1709b0b30ab65471a98023131f0e7620c/src/core/
ifetime.d#L124-L128 if you want to fix it (std.conv.emplace is now an alias for
core.lifetime.emplace in Phobos master).

vitamin <vit vit.vit> writes:

On Thursday, 28 January 2021 at 23:18:21 UTC, kinke wrote:
 On Thursday, 28 January 2021 at 21:15:49 UTC, vitamin wrote:
 Is there reason why std.conv.emplace doesn't forward arguments 
 to __ctor?

 Yeah, a bug in the emplace() version for classes, some missing 
 `forward!args` in there (it works when emplacing a struct with 
 identical ctor). E.g. 
 https://github.com/dlang/druntime/blob/e2e304e1709b0b30ab65471a98023131f0e7620c/src/core/
ifetime.d#L124-L128 if you want to fix it (std.conv.emplace is now an alias for
core.lifetime.emplace in Phobos master).

thanks;

kinke <noone nowhere.com> writes:

On Saturday, 30 January 2021 at 17:29:15 UTC, vitamin wrote:
 On Thursday, 28 January 2021 at 23:18:21 UTC, kinke wrote:
 On Thursday, 28 January 2021 at 21:15:49 UTC, vitamin wrote:
 Is there reason why std.conv.emplace doesn't forward 
 arguments to __ctor?

 Yeah, a bug in the emplace() version for classes, some missing 
 `forward!args` in there (it works when emplacing a struct with 
 identical ctor). E.g. 
 https://github.com/dlang/druntime/blob/e2e304e1709b0b30ab65471a98023131f0e7620c/src/core/
ifetime.d#L124-L128 if you want to fix it (std.conv.emplace is now an alias for
core.lifetime.emplace in Phobos master).

 thanks;

It's already fixed: https://github.com/dlang/druntime/pull/3352