http://d.puremagic.com/issues/show_bug.cgi?id=1715

           Summary: Template specialization checks for equality rather than
                    convertibility
           Product: D
           Version: 2.008
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Keywords: rejects-valid, spec
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: dhasenan@gmail.com


This is related to #1714: the workaround for 1714 is prevented by this, and vice versa.

When specializing a template based on the template parameters of its argument, a check is performed for equality, not convertibility. For every other type specialization, a check is performed for convertibility rather than equality. (Equality would be redundant in those situations, and pretty much every situation.)

Example:
---
class Foo(T){}
class Bar : Foo!(int) {}
template GetFooArg (T : Foo!(U), U) {
   alias U GetFooArg;
}

static assert (is (GetFooArg!(Foo!(int)) == int)); // works
static assert (is (GetFooArg!(Bar) == int)); // false
pragma (msg, GetFooArg!(Bar).stringof); // template instance GetFooArg!(Bar)
// does not match any template declaration
---


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http://d.puremagic.com/issues/show_bug.cgi?id=1715


Don <clugdbug@yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
                 CC|                            |clugdbug@yahoo.com.au


--- Comment #1 from Don <clugdbug@yahoo.com.au> 2010-09-03 11:26:31 PDT ---
The patch in bug 4173 fixes this.

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Walter Bright <bugzilla@digitalmars.com> changed:

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


--- Comment #2 from Walter Bright <bugzilla@digitalmars.com> 2010-09-11 17:52:32 PDT ---
http://www.dsource.org/projects/dmd/changeset/675

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Mike Linford <mike.linford@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mike.linford@gmail.com
         Resolution|FIXED                       |INVALID


--- Comment #3 from Mike Linford <mike.linford@gmail.com> 2010-09-15 23:52:54 PDT ---
(In reply to comment #2)
> http://www.dsource.org/projects/dmd/changeset/675

DMD 1.063 gives the same results for the given example and an example in my personal code.

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Don <clugdbug@yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|INVALID                     |FIXED


--- Comment #4 from Don <clugdbug@yahoo.com.au> 2010-09-16 00:09:24 PDT ---
(In reply to comment #3)
> (In reply to comment #2)
> > http://www.dsource.org/projects/dmd/changeset/675
> 
> DMD 1.063 gives the same results for the given example and an example in my personal code.

Yes, of course.

Why did you mark this as invalid???? The bug is definitely valid, and it's
fixed in the upcoming beta.
Please don't do this sort of thing again.

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--- Comment #5 from Mike Linford <mike.linford@gmail.com> 2010-09-16 09:34:29 PDT ---
(In reply to comment #4)
> (In reply to comment #3)
> > (In reply to comment #2)
> > > http://www.dsource.org/projects/dmd/changeset/675
> > 
> > DMD 1.063 gives the same results for the given example and an example in my personal code.
> 
> Yes, of course.
> 
> Why did you mark this as invalid???? The bug is definitely valid, and it's
> fixed in the upcoming beta.
> Please don't do this sort of thing again.

I guess I'm confused. It's claimed that the bug was resolved, but the latest version has the bug. Since the latest version in fact hasn't resolved the bug, doesn't that mean that the resolution was invalid?

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--- Comment #6 from Don <clugdbug@yahoo.com.au> 2010-09-17 01:26:19 PDT ---
(In reply to comment #5)
> (In reply to comment #4)
> > (In reply to comment #3)
> > > (In reply to comment #2)
> > > > http://www.dsource.org/projects/dmd/changeset/675
> > > 
> > > DMD 1.063 gives the same results for the given example and an example in my personal code.
> > 
> > Yes, of course.
> > 
> > Why did you mark this as invalid???? The bug is definitely valid, and it's
> > fixed in the upcoming beta.
> > Please don't do this sort of thing again.
> 
> I guess I'm confused. It's claimed that the bug was resolved, but the latest version has the bug. Since the latest version in fact hasn't resolved the bug, doesn't that mean that the resolution was invalid?

1.063 is not the latest version. (BTW, if the bug was still not fixed, you'd
mark it as 'REOPENED' not INVALID).
Bugs get marked as fixed when they are fixed in svn, not when a release happens
(the inability to distinguish between the two is something I intensely dislike
about Bugzilla).

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