https://issues.dlang.org/show_bug.cgi?id=14198

--- Comment #1 from Kenji Hara <k.hara.pg@gmail.com> ---
Introduced in: https://github.com/D-Programming-Language/dmd/pull/4335

But i'm not sure what is the problem.

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https://issues.dlang.org/show_bug.cgi?id=14198

Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla@digitalmars.com

--- Comment #2 from Walter Bright <bugzilla@digitalmars.com> ---
This reduces to:

---
import std.conv;

struct S
{
    ptrdiff_t function() fptr = &handler;

    static ptrdiff_t handler()
    {
        static if (is(typeof(to!(string)(false))))
        {
            to!(string)(false);
        }
        return 0;
    }

}

void main()
{
}
---
I don't think it has anything to do with 4335, but with emitting instantiations done during a typeof.

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https://issues.dlang.org/show_bug.cgi?id=14198

--- Comment #3 from Walter Bright <bugzilla@digitalmars.com> ---
This is crazy complicated.

What's happening is in TemplateInstance::needsCodegen(), the minst for to!string is set to std.bitmanip, which is not a root module, and so needsCodegen() says it should be in Phobos.lib. However, std.bitmanip never actually instantiates to!string, so it is not found in phobos.lib, and the link fails.

_D3std4conv11__T2toTAyaZ9__T2toTbZ2toFbZAya is to!string

So, to!string's minst is being set wrong.

The wrong value is set by this code in TemplateInstance::semantic():
---------------
// If the first instantiation was speculative, but this is not:
if (!inst->minst)
{
    // Mark it is a non-speculative instantiation.
    inst->minst = minst;  <---- here
}
---------------
minst is set to std.bitmanip during the evaluation of std.bitmanip.FloatRep, which calls:
--------------
mixin(bitfields!(
          uint,  "fraction", 23,
          ubyte, "exponent",  8,
          bool,  "sign",      1));
---------------
which winds up calling to!string at some point with sc->minst set to std.bitmanip.

I don't know why to!string is not emitted when Phobos is built.

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https://issues.dlang.org/show_bug.cgi?id=14198

--- Comment #4 from Walter Bright <bugzilla@digitalmars.com> ---
Hmm, a reference to:

  _D3std4conv11__T2toTAyaZ9__T2toTbZ2toFbZAya

is generated, but there's a:

  _D3std4conv11__T2toTAyaZ9__T2toTbZ2toFNaNfbZAya

in Phobos. The difference is the latter is Na (pure) and Nf (@safe).

So, somehow attribute inference is happening in the latter but not the former.

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https://issues.dlang.org/show_bug.cgi?id=14198

--- Comment #5 from Walter Bright <bugzilla@digitalmars.com> ---
https://github.com/D-Programming-Language/phobos/pull/3038

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https://issues.dlang.org/show_bug.cgi?id=14198

--- Comment #6 from Kenji Hara <k.hara.pg@gmail.com> ---
Created attachment 1480
  --> https://issues.dlang.org/attachment.cgi?id=1480&action=edit
Reduced test case. Running ng.bat will reproduce link-failure.

(In reply to Kenji Hara from comment #1)
> Introduced in: https://github.com/D-Programming-Language/dmd/pull/4335

Sorry I was wrong. The issue commit that was introducing the change was in Phobos repository.

https://github.com/D-Programming-Language/phobos/commit/a9d45235da6509e21450dea1825a5fa1dff9eed4#diff-54cf8402b22024ae667d4048a5126f0eL17

The commit has removed `import std.string;` from the module level scope in std.array. Unfortunately it triggered a previously unknown forward reference bug in compiler.

See also the minimized test case I attached.

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https://issues.dlang.org/show_bug.cgi?id=14198

github-bugzilla@puremagic.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

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https://issues.dlang.org/show_bug.cgi?id=14198

--- Comment #7 from github-bugzilla@puremagic.com ---
Commits pushed to master at https://github.com/D-Programming-Language/phobos

https://github.com/D-Programming-Language/phobos/commit/646dc1969c78fdf43b981b973783efba08b11354 fix Issue 14198 - [REG2.067a] Link failure with Variant

https://github.com/D-Programming-Language/phobos/commit/8598139bde54ffa8e0888b965f11e3ac79914661 Merge pull request #3038 from WalterBright/fix14198

fix Issue 14198 - [REG2.067a] Link failure with Variant

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https://issues.dlang.org/show_bug.cgi?id=14198

--- Comment #8 from github-bugzilla@puremagic.com ---
Commits pushed to master at https://github.com/D-Programming-Language/phobos

https://github.com/D-Programming-Language/phobos/commit/77b9b31bb6484c87e45b1df787cd58a4452d05f2 fixup #3038 add reference to bugzilla issue 14198

https://github.com/D-Programming-Language/phobos/commit/74d2c8aa799297ef404055390cbf24c04c94248c Merge pull request #3044 from MartinNowak/fixup3038

fixup #3038 add reference to bugzilla issue 14198

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https://issues.dlang.org/show_bug.cgi?id=14198

Kenji Hara <k.hara.pg@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |---

--- Comment #9 from Kenji Hara <k.hara.pg@gmail.com> ---
Fix inherent issue in compiler: https://github.com/D-Programming-Language/dmd/pull/4464

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