[Bug c++/11357] New: no conversion of build-in binary operator argument attempted

[Bug c++/11357] New: no conversion of build-in binary operator argument attempted

[d dot frey at gmx dot de]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357

           Summary: no conversion of build-in binary operator argument
                    attempted
           Product: gcc
           Version: 3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: d dot frey at gmx dot de
                CC: gcc-bugs at gcc dot gnu dot org

Consider the following code snippet:

struct A {
    template< typename T > operator T() const;
} a;

template<> A::operator float() const
{
    return 1.0f;
}

int main()
{
    float f = 1.0f * a;
}

The GCC 3.3 says:

t.cc: In function `int main()':
t.cc:12: error: no match for `float * A&' operator
t.cc:12: warning: unused variable `float f'

which is probably incorrect. EDG-based compilers like the code and 5.6/2 and 5/9
suggest that they are right. The GCC seems to be unable to decide which
conversion is appopriate and thus fails to attempt to cast A to float. This is
in the GCC since (at least) 2.95.3.

Regards, Daniel

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[bangerth at dealii dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357


bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nathan at codesourcery dot
                   |                            |com, giovannibajo at libero
                   |                            |dot it


------- Additional Comments From bangerth at dealii dot org  2003-06-28 18:00 -------
Confirmed up to mainline, icc compiles this fine.

I think the claim should be valid, though I must admit that I'm at a loss as
to which conversion the compiler should choose. The existence of the
specialization is irrelevant in this context, so the compiler could choose
a conversion to float or double, for example.

I'll leave this to other language lawyers.

W.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[nathan at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357


nathan at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-06-28 18:06:48
               date|                            |


------- Additional Comments From nathan at gcc dot gnu dot org  2003-06-28 18:06 -------
it should choose the specialization. one of the builtin candidates is
operator *(float, float)

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[giovannibajo at libero dot it]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From giovannibajo at libero dot it  2003-06-30 00:07 -------
The bug lies in add_builtin_candidates, cp/call.c:2178: the for-loop that goes 
through the conversion functions looked up through lookup_conversions does not 
check for TEMPLATE_DECLs (it should then probably use add_template_candidate to 
generate a potential instantiation). But I can't handle the details, it's too 
difficult for me.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[giovannibajo at libero dot it]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From giovannibajo at libero dot it  2003-07-01 07:45 -------
Subject: 

Daniel Frey <daniel.frey@aixigo.de> wrote:

> In case you missed it: I just want to let you know that some Core WG
> members are still discussing what should be the correct behaviour for
> this case is. See csc++, "Language lawyers: template operator selection".
> Regards, Daniel

Is there an open defect report for this item? I could not find it.

Giovanni Bajo

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[daniel dot frey at aixigo dot de]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From daniel dot frey at aixigo dot de  2003-07-01 07:52 -------
Subject: Re: 

Giovanni Bajo wrote:
> Daniel Frey <daniel.frey@aixigo.de> wrote:
> 
> 
>>In case you missed it: I just want to let you know that some Core WG
>>members are still discussing what should be the correct behaviour for
>>this case is. See csc++, "Language lawyers: template operator selection".
>>Regards, Daniel
> 
> 
> Is there an open defect report for this item? I could not find it.

As Daveed said in his latest posting, it *will* be opened to track the 
issue.

Regards, Daniel

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[giovannibajo at libero dot it]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357


giovannibajo at libero dot it changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |SUSPENDED


------- Additional Comments From giovannibajo at libero dot it  2003-07-01 08:27 -------
Suspended till the defect report is resolved.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[pinskia at physics dot uc dot edu]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357


pinskia at physics dot uc dot edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.4                         |---

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[pinskia at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-09-08 04:29 -------
Note on the mainline, GCC accepts this one.  Any news on the DR?

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[d dot frey at gmx dot de]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From d dot frey at gmx dot de  2003-09-09 23:19 -------
Subject: Re:  no conversion of build-in binary operator
	argument attempted

On Mon, 2003-09-08 at 06:29, pinskia at gcc dot gnu dot org wrote:
> Note on the mainline, GCC accepts this one.  Any news on the DR?

Not yet. I asked Daveed Vandervoorde, he told me that the DR was opened
and will be published with the next cycle. I'll keep an eye on it and
report any progress, but this will most likely not happen before
November. Since than, the GCC is not to blame for any behaviour as both
ways are... !wrong :)

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[pinskia at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-09-09 23:54 -------
I think this was fixed when PR 11684 was fixed.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[bangerth at dealii dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From bangerth at dealii dot org  2003-09-10 00:17 -------
No, on the contrary: where the error message was 
  x.cc: In function `int main()': 
  x.cc:12: error: no match for `float * A&' operator 
it is now 
  x.cc: In function `int main()': 
  x.cc:12: error: no match for 'operator*' in '1.0e+0 * a' 
That's more confusing, since we drop the information that 1.0e+0 is actually a float, 
now a double as one could think from just seeing the message. 
 
W.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[gdr at integrable-solutions dot net]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From gdr at integrable-solutions dot net  2003-09-10 01:17 -------
Subject: Re:  no conversion of build-in binary operator argument attempted

"bangerth at dealii dot org" <gcc-bugzilla@gcc.gnu.org> writes:
| No, on the contrary: where the error message was 
|   x.cc: In function `int main()': 
|   x.cc:12: error: no match for `float * A&' operator 
| it is now 
|   x.cc: In function `int main()': 
|   x.cc:12: error: no match for 'operator*' in '1.0e+0 * a' 
| That's more confusing, since we drop the information that 1.0e+0 is
| actually a float, now a double as one could think from just seeing
| the message.  

What is confusing in the display of the literal.  Can you assign this
to me?  Thanks.

-- Gaby

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[bangerth at dealii dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357


bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |gdr at gcc dot gnu dot org
                   |dot org                     |
             Status|SUSPENDED                   |ASSIGNED


------- Additional Comments From bangerth at dealii dot org  2003-09-10 01:50 -------
What is confusing is that we are looking for a match 
  float * A 
but the message says that we are looking for 
  1.0 * a 
i.e. it gives values instead of types. From the value 1.0 it is not clear that this 
should be a float; in fact, one would think that the first argument needs to be 
a double instead, since the numeric literal 1.0 has type double. 
 
W.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[gdr at integrable-solutions dot net]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From gdr at integrable-solutions dot net  2003-09-10 03:07 -------
Subject: Re:  no conversion of build-in binary operator argument attempted

"bangerth at dealii dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| What is confusing is that we are looking for a match 
|   float * A 
| but the message says that we are looking for 
|   1.0 * a 
| i.e. it gives values instead of types.

Printing expressions is the right thing to do.  However, the defect is
in printing 1.0 instead of 1.0f.

-- Gaby

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[bangerth at dealii dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From bangerth at dealii dot org  2003-09-10 13:36 -------
OK, that's just as fine with me. 
W.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[cvs-commit at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-09-17 17:56 -------
Subject: Bug 11357

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	gdr@gcc.gnu.org	2003-09-17 17:56:43

Modified files:
	gcc            : ChangeLog c-pretty-print.c 

Log message:
	PR c++/11357
	* c-pretty-print.c (pp_c_floating_constant): Append
	type-annotation to floating constants.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.1077&r2=2.1078
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-pretty-print.c.diff?cvsroot=gcc&r1=1.26&r2=1.27

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[gdr at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357


gdr at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|gdr at gcc dot gnu dot org  |unassigned at gcc dot gnu
                   |                            |dot org
             Status|ASSIGNED                    |NEW


------- Additional Comments From gdr at gcc dot gnu dot org  2003-09-17 22:00 -------
This is not a diagnostic per se and I don't plan to investigate
this bug further.

[Bug c++/11357] no conversion of build-in binary operator argument attempted

[d dot frey at gmx dot de]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357



------- Additional Comments From d dot frey at gmx dot de  2003-09-21 22:29 -------
The related DR is #425

[Bug c++/11357] [DR 425?] no conversion of build-in binary operator argument attempted

[pinskia at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |SUSPENDED
            Summary|no conversion of build-in   |[DR 425?] no conversion of
                   |binary operator argument    |build-in binary operator
                   |attempted                   |argument attempted


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-09-22 00:14 -------
Suspending untill DR's are filed and/or resolved.

[Bug c++/11357] [DR 425?] no conversion of build-in binary operator argument attempted

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
   Last reconfirmed|2003-12-22 00:03:48         |2004-04-26 20:02:36
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357

[Bug c++/11357] [DR 425] no conversion of build-in binary operator argument attempted

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-04-30 02:54 -------
The DR is now in WP so change back to NEW.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|SUSPENDED                   |NEW
   Last reconfirmed|2004-04-26 20:02:36         |2004-04-30 02:54:00
               date|                            |
            Summary|[DR 425?] no conversion of  |[DR 425] no conversion of
                   |build-in binary operator    |build-in binary operator
                   |argument attempted          |argument attempted


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11357