[Bug debug/14971] New: error message is correct, but could be more helpful

[Bug debug/14971] New: error message is correct, but could be more helpful

[tjic_gccbugs at tjic dot com]

when attempting to partially specialize a function template, the error message 
is generated:

   partial specialization `....` of function template

this is absolutely accurate, yet for someone stuck in a certain frame of mind, 
it's not maximally helpful.  Specifically: if it just doesn't occur to a block-
headed user (i.e. me) that a partial specialization of a function template is 
illegal, the response is likely to be "yes, I know, that's exactly what I want 
to do...so why is the compiler complaining?".

I suggest a change of the message to 

    partial specialization `....` of function template; illegal C++

or somesuch.

Thanks for considering this,

TJIC

-- 
           Summary: error message is correct, but could be more helpful
           Product: gcc
           Version: 3.2.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tjic_gccbugs at tjic dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-04-15 22:50 -------
Confirmed. I assume you had something like this in mind: 
------------------ 
template <typename U, typename V> 
void f(U,V) {}; 
 
template <typename U> 
void f<U,int> (U, int) {}; 
------------------ 
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc 
x.cc:5: error: partial specialization `f<U, int>' of function template 
 
Even though I consider myself an experienced C++ user, I have run into 
this before as well, and a description of _why_ this is an error (because 
the standard says it is illegal) would certainly be helpful. I suggest that 
something like 
  partial specializations `...'; partial specializations of function 
  templates are not allowed in C++ 
would be a better wording. 
 
W. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gdr at gcc dot gnu dot org
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |NEW
          Component|debug                       |c++
     Ever Confirmed|                            |1
           Keywords|                            |diagnostic
   Last reconfirmed|0000-00-00 00:00:00         |2004-04-15 22:50:29
               date|                            |
            Summary|error message is correct,   |better error message for
                   |but could be more helpful   |partial specialization of
                   |                            |function templates requested


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-04-15 22:58 -------
For comparison here what ICC 6.0 gives:
pr14971.cc
pr14971.cc(5): error: an explicit template argument list is not allowed on this declaration
  void f<U,int> (U, int) {};
       ^

compilation aborted for pr14971.cc (code 2)

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[tjic at tjic dot com]

------- Additional Comments From tjic at tjic dot com  2004-04-15 23:04 -------
Subject: Re:  better error message for partial specialization of function templates requested


>  Date: 15 Apr 2004 22:50:30 -0000
>  From: "bangerth at dealii dot org" <gcc-bugzilla@gcc.gnu.org>
>  
>  
>  ------- Additional Comments From bangerth at dealii dot org  2004-04-15 22:50 -------
>  Confirmed. I assume you had something like this in mind: 
>  ------------------ 
>  template <typename U, typename V> 
>  void f(U,V) {}; 
>   
>  template <typename U> 
>  void f<U,int> (U, int) {}; 
>  ------------------ 
>  g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc 
>  x.cc:5: error: partial specialization `f<U, int>' of function template 

Exactly.
   
>  Even though I consider myself an experienced C++ user, I have run into 
>  this before as well, and a description of _why_ this is an error (because 
>  the standard says it is illegal) would certainly be helpful. I suggest that 
>  something like 
>    partial specializations `...'; partial specializations of function 
>    templates are not allowed in C++ 
>  would be a better wording.

A fine improvement!

Thanks,

TJIC





-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-04-15 23:34 -------
Subject: Re:  better error message for partial specialization of function templates requested

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

| Even though I consider myself an experienced C++ user, I have run into 
| this before as well, and a description of _why_ this is an error (because 
| the standard says it is illegal) would certainly be helpful. I suggest that 
| something like 
|   partial specializations `...'; partial specializations of function 
|   templates are not allowed in C++ 
| would be a better wording. 

I agree with you.  Do you have a patch around?

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-04-16 13:42 -------
This is so trivial that it can probably slip in without a copyright 
assignment. I don't know whether this is the right way to handle long 
error messages, and also note that this is completely untested (no 
time, sorry). 
 
W. 
 
2004-04-16  Wolfgang Bangerth  (bangerth@dealii.org) 
 
        PR c++/14971 
	* pt.c (check_explicit_specialization): Improve wording of 
	error message 
 
 
Index: pt.c 
=================================================================== 
RCS file: /cvsroot/gcc/gcc/gcc/cp/pt.c,v 
retrieving revision 1.816.2.23 
diff -c -r1.816.2.23 pt.c 
*** pt.c        31 Mar 2004 02:09:59 -0000      1.816.2.23 
--- pt.c        16 Apr 2004 13:40:03 -0000 
*************** 
*** 1696,1702 **** 
             template <class T> void f<int>(); */ 
   
          if (uses_template_parms (declarator)) 
!           error ("partial specialization `%D' of function template", 
                      declarator); 
          else 
            error ("template-id `%D' in declaration of primary template", 
--- 1696,1703 ---- 
             template <class T> void f<int>(); */ 
   
          if (uses_template_parms (declarator)) 
!           error ("partial specialization `%D'; partial specializations " 
!                    "of function templates are not allowed in C++", 
                      declarator); 
          else 
            error ("template-id `%D' in declaration of primary template", 
 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-04-16 16:20 -------
Subject: Re:  better error message for partial specialization of function templates requested

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

| This is so trivial that it can probably slip in without a copyright 
| assignment. I don't know whether this is the right way to handle long 
| error messages, and also note that this is completely untested (no 
| time, sorry). 

Thanks for doing this.

I would suggest the slightly variation:

[...]

| --- 1696,1703 ---- 
|              template <class T> void f<int>(); */ 
|    
|           if (uses_template_parms (declarator)) 
| !           error ("partial specialization `%D'; partial specializations " 
| !                    "of function templates are not allowed in C++", 
|                       declarator); 

  error ("function template partial specialization is not allowed");

With that change, the patch is approved (can you commit?).

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-04-16 16:23 -------
No, I don't have any CVS writable tree checked out any more. Someone 
else will have to do it for me. 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

Re: [Bug c++/14971] better error message for partial specialization of function templates requested

[Zack Weinberg]

English would prefer "partial specializations of function templates
are not allowed".

zw

[Bug c++/14971] better error message for partial specialization of function templates requested

[zack at codesourcery dot com]

------- Additional Comments From zack at codesourcery dot com  2004-04-16 21:24 -------
Subject: Re:  better error message for partial specialization
 of function templates requested


English would prefer "partial specializations of function templates
are not allowed".

zw


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-04-16 22:33 -------
With which we are back to my orginal patch :-) 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-04-17 17:28 -------
Subject: Re:  better error message for partial specialization of function templates requested

"zack at codesourcery dot com" <gcc-bugzilla@gcc.gnu.org> writes:

| English would prefer "partial specializations of function templates
| are not allowed".

If we must quibble, then I'm pretty sure English would prefer
"specialisation" ;-/.

More seriously, the terminology used in the C++ community seems to be
  "function template partial specialization".

google should give some hits.  I got 2 hits for Zack's suggestion
(including Giovanni's title) and lots for the version I proposed.

I still maintain "function template partial specialization", because
it is consistent with the rest of the terminology.

-- Gaby




-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-04-18 17:35 -------
I think we have had this conversation before: should error messages 
be in legalese, or in a language that a typical programmer would use 
when talking to a colleague. I personally prefer the latter, Gaby 
apparently the former. 
 
However, if we continue to discuss these matters, we won't check in 
any patch ever. Can someone please check in whatever (s)he thinks 
appropriate? I'm happy to go with whatever... 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-04-18 17:52 -------
Subject: Re:  better error message for partial specialization of function templates requested

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

| I think we have had this conversation before: should error messages 
| be in legalese, or in a language that a typical programmer would use 
| when talking to a colleague. I personally prefer the latter, Gaby 
| apparently the former. 

No, that is a true misrepresentation of my position.  I think the error
messages should 

  (1) use terminology established in the community, where possible;
  (2) be simple as possible and comprehensible to C++ programmers.

Mistating my position does not automatically make your position
better.  There is no point is inventing new terminology.

I've given hints as to how frequent you may find use of the
terminology I used earlier.  Does the following help you?

     http://www.gotw.ca/publications/mill17.htm 

| However, if we continue to discuss these matters, we won't check in 
| any patch ever. Can someone please check in whatever (s)he thinks 
| appropriate? I'm happy to go with whatever... 

I'm going to check the patch in a moment, as I'm checking in other
patches.

-- Gaby



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-04-18 18:16 -------
Thanks, Gaby. I apologize if I misinterpreted you position. I just sometimes 
have the feeling that the terminology used in CS/language standards/similar 
communities is not necessarily the same that is used by Joe User. Nevermind. 
Thanks for checking it in. 
 
As to researching on the web: If I search for the following exact 
phrases, I get on google (don't ask me what the 'about' is about): 
  "partial specialization of function templates": about 105 
  "partial specialization of function template":  about 21 
  "function template partial specialization":     about 8 
  "function template partial specializations":    none 
What did I do differently than you? 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

Re: [Bug c++/14971] better error message for partial specialization of function templates requested

[Gabriel Dos Reis]

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

| ------- Additional Comments From bangerth at dealii dot org  2004-04-18 18:16 -------
| Thanks, Gaby. I apologize if I misinterpreted you position. I just sometimes 
| have the feeling that the terminology used in CS/language standards/similar 
| communities is not necessarily the same that is used by Joe User. Nevermind. 
| Thanks for checking it in. 
|  
| As to researching on the web: If I search for the following exact 
| phrases, I get on google (don't ask me what the 'about' is about): 
|   "partial specialization of function templates": about 105 
|   "partial specialization of function template":  about 21 
|   "function template partial specialization":     about 8 
|   "function template partial specializations":    none 
| What did I do differently than you? 

I just lanched google for

   "partial specialization of function template"

I got exactly 4 matches (against 3 yesterday), among which PR 7938 and
PR 14971 (i.e. this very thread).


  "function template partial specialization"

led to 12 matches.

I did not try the plural variations as you did. 

-- Gaby

[Bug c++/14971] better error message for partial specialization of function templates requested

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-04-18 18:25 -------
Subject: Re:  better error message for partial specialization of function templates requested

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

| ------- Additional Comments From bangerth at dealii dot org  2004-04-18 18:16 -------
| Thanks, Gaby. I apologize if I misinterpreted you position. I just sometimes 
| have the feeling that the terminology used in CS/language standards/similar 
| communities is not necessarily the same that is used by Joe User. Nevermind. 
| Thanks for checking it in. 
|  
| As to researching on the web: If I search for the following exact 
| phrases, I get on google (don't ask me what the 'about' is about): 
|   "partial specialization of function templates": about 105 
|   "partial specialization of function template":  about 21 
|   "function template partial specialization":     about 8 
|   "function template partial specializations":    none 
| What did I do differently than you? 

I just lanched google for

   "partial specialization of function template"

I got exactly 4 matches (against 3 yesterday), among which PR 7938 and
PR 14971 (i.e. this very thread).


  "function template partial specialization"

led to 12 matches.

I did not try the plural variations as you did. 

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-07-03 02:05 -------
Subject: Bug 14971

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	giovannibajo@gcc.gnu.org	2004-07-03 02:05:30

Modified files:
	gcc/cp         : ChangeLog pt.c 

Log message:
	PR c++/14971
	* pt.c (check_explicit_specialization): Clarify error message.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&r1=1.4157&r2=1.4158
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/pt.c.diff?cvsroot=gcc&r1=1.877&r2=1.878



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971

[Bug c++/14971] better error message for partial specialization of function templates requested

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-07-03 02:06 -------
Fixed for GCC 3.5.0, thank you for your report!

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14971