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digitalmars.D.bugs - [Issue 10083] New: Insufficient IFTI/eponymous template specification

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10083

           Summary: Insufficient IFTI/eponymous template specification
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: timon.gehr gmx.ch


--- Comment #0 from timon.gehr gmx.ch 2013-05-14 12:01:58 PDT ---
The spec does not say how IFTI and the eponymous template trick behave when the
eponymous declaration is overloaded.

DMD's strategy is roughly: use the first eponymous declaration that can be
found without analysing the template body for IFTI, then use the first
eponymous declaration in the analyzed template body to resolve the eponymous
declaration after instantiation.

---
import std.stdio;
template fun(T){
        int fun(double arg){ return 1; }
        int fun(T arg){ return 0; }
}
void main(){ writeln(fun(2)); } // error

---
import std.stdio;
template fun(T){
        int fun(T arg){ return 0; }
        int fun(double arg){ return 1; }
}
void main(){ writeln(fun(2)); } // ok

---

This has funny implications, as the compiler may decide to resolve to a
different declaration than was used for IFTI later, without doing any kind of
overload resolution within the template body.

---
template fun(T){
        int fun(T arg){ return 0; }
        static if(true) int fun(double arg){ return 1; }
}
pragma(msg, fun(2)); // 0
---
template fun(T){
        static if(true) int fun(double arg){ return 1; }
        int fun(T arg){ return 0; }
}
pragma(msg, fun(2)); // 1
---

In the second case, instantiation is performed with the second function, so T
is resolved to 'int', but in the end, the 'double' overload is called with an
implicit conversion.

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May 14 2013
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10083


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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull


--- Comment #1 from Kenji Hara <k.hara.pg gmail.com> 2013-05-22 22:21:53 PDT ---
https://github.com/D-Programming-Language/dmd/pull/2041

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May 22 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10083



--- Comment #2 from github-bugzilla puremagic.com 2013-06-26 22:17:15 PDT ---
Commits pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/10cf2d97cd8fffce312d8bf48ca4830ceb5bed05
fix Issue 10083 - Insufficient IFTI/eponymous template specification

https://github.com/D-Programming-Language/dmd/commit/ed83e21e69bce7dc4b7ef223c6e0cfb59013bf82
Merge pull request #2041 from 9rnsr/fix10083

Issue 10083 - Insufficient IFTI/eponymous template specification

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Jun 26 2013
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10083


Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |FIXED


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