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digitalmars.D.bugs - [Issue 4636] New: scoped + private constructor

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4636

           Summary: scoped + private constructor
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: dsimcha yahoo.com


--- Comment #0 from David Simcha <dsimcha yahoo.com> 2010-08-12 18:33:26 PDT ---
import std.typecons;

class Foo {
    private this(int num) {}
}

void main() {
    auto s = scoped!Foo(1);
}

d:\dmd2\windows\bin\..\..\src\phobos\std\conv.d(3903): Error: static assert 
"Don't know how to initialize an object of type Foo with arguments (int
_param_1)"
d:\dmd2\windows\bin\..\..\src\phobos\std\typecons.d(2314):        instantiated
from here: emplace!(Foo,int)
test9.d(8):        instantiated from here: scoped!(Foo,int)

Changing the c'tor to public fixes this.

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Aug 12 2010
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4636


monarchdodra gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |monarchdodra gmail.com


--- Comment #1 from monarchdodra gmail.com 2013-09-10 23:50:24 PDT ---
Is this really valid?

If the constructor is private, then how could "scoped" (or "emplace" in this
case) be expected to call it?

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Sep 10 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4636


Dicebot <public dicebot.lv> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |public dicebot.lv


--- Comment #2 from Dicebot <public dicebot.lv> 2013-09-11 08:17:54 PDT ---
This is invalid as per current D specification but once again highlights
fundamental flaw of protection attribute resolution done from definition scope
for templates.

Semantically it is the same module who constructs the Foo and access to private
constructor is expected. But in fact it is done in `scoped` body which does
reside in different module and this does not have access.

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Sep 11 2013
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4636


Maxim Fomin <maxim maxim-fomin.ru> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|rejects-valid               |
             Status|NEW                         |RESOLVED
                 CC|                            |maxim maxim-fomin.ru
           Platform|Other                       |All
         Resolution|                            |WONTFIX
         OS/Version|Windows                     |All


--- Comment #3 from Maxim Fomin <maxim maxim-fomin.ru> 2013-09-11 08:37:33 PDT
---
This can be probably fixed by providing additional parameter which takes a
delegate to private constructor (in a scope which have access to it) as an
argument (with default null value). But it looks like it would require hoard of
additional parameters along call chain which probably does not worth issue.
Right now I close it as WONTFIX, but if some wants to fix, this can be
reopened.

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