[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |

--- Comment #11 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
clang also rejects this code for the same reason as GCC.

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #12 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
We say

17000.C: In member function ‘void b<T>::func()’:
17000.C:10:17: warning: expected ‘template’ keyword before dependent template
name [-Wmissing-template-keyword]
   10 |         get_a().func2 <int>();
      |                 ^~~~~
      |                 template

and clang++ says

17000.C:10:17: error: use 'template' keyword to treat 'func2' as a dependent
template name
   10 |         get_a().func2 <int>();
      |                 ^
      |                 template 

I think we can close this.

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[ddneilson at gmail dot com]

------- Comment #10 from ddneilson at gmail dot com  2007-04-20 18:51 -------
(In reply to comment #9)
> (In reply to comment #8)
> > The work around is doing:
> >         get_a().template func2 <int>();
> > 
> > 
> > Which tells the compiler for sure func2 is a template.
> > 
> 
> Thanks, yeh I figured that out just now. Should it happen like this though?
> Surely the compiler should be able to work out it's a template and therefore
> not need the qualification?
> 

 I was just about to report a similar bug, but it was also "fixed" by adding a
"template" qualifier to the function call.  

 However, when studying the bug I ran my test case through the xlC compiler. It
compiles "get_a().func2<int>();" just fine; it doesn't need "get_a().template
func2<int>();" syntax.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[matt at galloway dot me dot uk]

------- Comment #9 from matt at galloway dot me dot uk  2007-03-18 11:01 -------
(In reply to comment #8)
> The work around is doing:
>         get_a().template func2 <int>();
> 
> 
> Which tells the compiler for sure func2 is a template.
> 

Thanks, yeh I figured that out just now. Should it happen like this though?
Surely the compiler should be able to work out it's a template and therefore
not need the qualification?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[pinskia at gcc dot gnu dot org]

------- Comment #8 from pinskia at gcc dot gnu dot org  2007-03-18 06:12 -------
The work around is doing:
        get_a().template func2 <int>();


Which tells the compiler for sure func2 is a template.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[matt at galloway dot me dot uk]

------- Comment #7 from matt at galloway dot me dot uk  2007-03-18 01:06 -------
Same problem for me with gcc-4.0.1. Is this going to get fixed or is it correct
behaviour and the code needs some sort of codeword to tell the compiler that
func2 is a template?


-- 

matt at galloway dot me dot uk changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |matt at galloway dot me dot
                   |                            |uk


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-08-12 15:15 -------
Again, the call to get_a() is of course dependent. However, the 
_return type_ is not. 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-08-12 14:58 -------
Confirmed, from someone who has not looked into the source, it seems like get get_a is being marked 
as dependent for some reason when it should not be.  But it seems werid that ICC 6.0 also reject this 
code even in struct mode.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |rejects-valid
      Known to fail|                            |2.95.3 3.3.3 3.0.4 3.4.0
                   |                            |3.5.0
   Last reconfirmed|0000-00-00 00:00:00         |2004-08-12 14:58:45
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-08-12 14:34 -------
OK I got confused and thought there was a way to change the return type on 
specialization, but there obviously can't be (at least without specialize the 
entire class). Then, it makes sense for the code to be valid as-is.

Both ICC and MSVC have support for implicit typename/template (even disabling 
extensions), so they can't help on this regard.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-08-12 14:20 -------
Your specialization is of course invalid the way you 
write it: it needs at least to have the same return type. 
 
The question I have is different: of course the call to 
get_a() is dependent, but its return type 'a' is not, and 
we know that it can never be since the call to get_a can 
be looked up at template definition time, so the return 
type 'a' is fixed at that time. So if we know the return  
type, why would we need the '.template' disambiguation? 
 
BTW: icc8 accepts the code with or without disambiguation, 
even in strict mode. Now, whether that means something is surely 
a different matter :) 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-08-12 13:41 -------
No, get_a() is a dependent call, since it's a short form for this->get_a(). 

Consider what happens if you specialize get_a after the definition of func(), 
such as:

template <>
void b<float>::get_a() {}


The compiler is right, you have to specify that "func2" is a member template of 
whatever get_a() returned, so you need an explicit "template" keyword.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000

[Bug c++/17000] parse error calling member template function of non-lvalue from within template class member

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-08-12 13:29 -------
I would concur, but am not quite sure. It would seem as if 
get_a() is a non-dependent call producing just an object of 
type 'a', so one should be able to simply call a member 
template as you do. What gcc expects, instead, is that you write 
  get_a().template func2<int> (); 
 
Giovanni, what do you say? 
 
W. 

-- 
           What    |Removed                     |Added
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                 CC|                            |giovannibajo at gcc dot gnu
                   |                            |dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17000