[Bug c++/44906] New: g++ is giving error: parse error in template argument list while using a c++ code.

[Bug c++/44906] New: g++ is giving error: parse error in template argument list while using a c++ code.

[raychaudhuri_amitava at yahoo dot com]

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amitavac@whileliesent-lm:~/data/prog/c++/template_ptr$g++ -v -o template
template.cpp 
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.4.3-4ubuntu5'
--with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--enable-multiarch --enable-linker-build-id --with-system-zlib
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls
--enable-clocale=gnu --enable-libstdcxx-debug --enable-plugin --enable-objc-gc
--enable-targets=all --disable-werror --with-arch-32=i486 --with-tune=generic
--enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu
--target=i486-linux-gnu
Thread model: posix
gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) 
COLLECT_GCC_OPTIONS='-v' '-o' 'template' '-shared-libgcc' '-mtune=generic'
'-march=i486'
 /usr/lib/gcc/i486-linux-gnu/4.4.3/cc1plus -quiet -v -D_GNU_SOURCE template.cpp
-D_FORTIFY_SOURCE=2 -quiet -dumpbase template.cpp -mtune=generic -march=i486
-auxbase template -version -fstack-protector -o /tmp/ccZiqQ9b.s
GNU C++ (Ubuntu 4.4.3-4ubuntu5) version 4.4.3 (i486-linux-gnu)
        compiled by GNU C version 4.4.3, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/i486-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../i486-linux-gnu/include"
ignoring nonexistent directory "/usr/include/i486-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/c++/4.4
 /usr/include/c++/4.4/i486-linux-gnu
 /usr/include/c++/4.4/backward
 /usr/local/include
 /usr/lib/gcc/i486-linux-gnu/4.4.3/include
 /usr/lib/gcc/i486-linux-gnu/4.4.3/include-fixed
 /usr/include
End of search list.
GNU C++ (Ubuntu 4.4.3-4ubuntu5) version 4.4.3 (i486-linux-gnu)
        compiled by GNU C version 4.4.3, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 35224f2c24023afb0a5be7befe8d5f3f
template.cpp: In member function ‘void MISC<T, P>::add(int)’:
template.cpp:55: error: parse error in template argument list
template.cpp:58: error: parse error in template argument list
template.cpp:61: error: parse error in template argument list
template.cpp:64: error: parse error in template argument list
template.cpp: In member function ‘void MISC<T, P>::print(int)’:
template.cpp:72: error: parse error in template argument list
template.cpp:75: error: parse error in template argument list
template.cpp:78: error: parse error in template argument list
template.cpp:81: error: parse error in template argument list

Following is the content of template.cpp (please let me know whats wrong with
the following program):
#include<stdint.h>

#include<iostream>
#include<vector>
#include<set>

using namespace std;

template<typename T, typename P>
class MISC{
        private:
                vector<T> vec1;
                vector<T> vec2;

                set<T> st1;
                set<T> st2;

                vector<P> *ptr;
        private:
                template<vector<T>* vc>
                        void addVecVals(){
                                for(T i=0; i<10;i++)
                                {
                                        vc->push_back(i);
                                }
                        }

                template<set<T>* st>
                        void addStVals(){
                                for(T i=0; i<10;i++)
                                {
                                        st->insert(i);
                                }
                        }

                template<vector<T>* vc>
                        void printVecVals(){
                                for(typename vector<T>::iterator i=vc->begin(),
j=vc->end(); i!=j;++i)
                                {
                                        cout<<"val = "<<*i<<" , ";
                                }
                        }

                template<set<T>* st>
                        void printStVals(){
                                for(typename set<T>::iterator i=st->begin(),
j=st->end(); i!=j;++i)
                                {
                                        cout<<"val = "<<*i<<" , ";
                                }
                        }
        public:
                void add(int vecNum) {
                        switch(vecNum) {
                                case 0: //vecs.
                                        addVecVals<&vec1>();
                                        break;
                                case 1:
                                        addVecVals<&vec2>();
                                        break;
                                case 2: //sets
                                        addStVals<&st1>();
                                        break;
                                case 3:
                                        addStVals<&st2>();
                                        break;
                                default: break;
                        }
                }
                void print(int vecNum) {
                        switch(vecNum) {
                                case 0: //vecs.
                                        printVecVals<&vec1>();
                                        break;
                                case 1:
                                        printVecVals<&vec2>();
                                        break;
                                case 2: //sets
                                        printStVals<&st1>();
                                        break;
                                case 3:
                                        printStVals<&st2>();
                                        break;
                                default: break;
                        }
                }
};

int main(void) {
        MISC<uint64_t, double> m;
        m.add(0);
        m.add(1);
        m.add(2);
        m.add(3);
        return 0;
}


-- 
           Summary: g++ is giving error: parse error in template argument
                    list while using a c++ code.
           Product: gcc
           Version: 4.4.3
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: raychaudhuri_amitava at yahoo dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[raychaudhuri_amitava at yahoo dot com]

------- Comment #1 from raychaudhuri_amitava at yahoo dot com  2010-07-10 15:44 -------
Created an attachment (id=21176)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21176&action=view)
Code which is failing.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[raychaudhuri_amitava at yahoo dot com]

------- Comment #3 from raychaudhuri_amitava at yahoo dot com  2010-07-10 15:45 -------
Created an attachment (id=21178)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21178&action=view)
.ii file generated by -save-temps


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[raychaudhuri_amitava at yahoo dot com]

------- Comment #2 from raychaudhuri_amitava at yahoo dot com  2010-07-10 15:44 -------
Created an attachment (id=21177)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21177&action=view)
.s file generated by -save-temps


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2010-07-10 17:46 -------
The error message is not clear.  The issue is that you are not using a constant
expression for a template arugment.  Template arguments are either constant
expressions or types.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[raychaudhuri_amitava at yahoo dot com]

------- Comment #5 from raychaudhuri_amitava at yahoo dot com  2010-07-10 18:45 -------
(In reply to comment #4)
> The error message is not clear.  The issue is that you are not using a constant
> expression for a template arugment.  Template arguments are either constant
> expressions or types.
> 

Whenever I will be using this kind of template in a class, the variable name is
predefined. Now when I create an object and call the function, it will get the
address offset and thus should be able to create an instance of that function
with same prototype but different body, else for such cases we have to create
different functions for each member. 

Can it be a new feature in g++ compiler? This will make function and objects as
first class citizen in C++. We can create function at runtime with different
object embedded in it. (I know it can be done by #define, but this is a better
way I think.)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[paolo dot carlini at oracle dot com]

------- Comment #6 from paolo dot carlini at oracle dot com  2010-07-10 22:19 -------
Honestly, nothing similar will happen any time soon, it means changing
completely the semantics of templates. Maybe we can produce a better
diagnostics, let's add Manuel in CC to hear his opinion...


-- 

paolo dot carlini at oracle dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |manu at gcc dot gnu dot org
           Severity|major                       |enhancement
           Keywords|                            |diagnostic


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
   Last reconfirmed|                            |2011-09-23
         Resolution|INVALID                     |
     Ever Confirmed|0                           |1

--- Comment #9 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-23 14:43:26 UTC ---
Hey, you woke up! ;) Sure, let's re-open is a diagnostic issue, your call.

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

--- Comment #8 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2011-09-23 13:59:07 UTC ---
(In reply to comment #6)
> Honestly, nothing similar will happen any time soon, it means changing
> completely the semantics of templates. Maybe we can produce a better
> diagnostics, let's add Manuel in CC to hear his opinion...

The code is invalid but the diagnostic could be much better (I only have GCC
4.5.2, so perhaps it is better in trunk).

Smaller testcase:

template<typename T>
class MISC{
public:
    T vec1;
    template<T* vc> void addVecVals(){};
    void add(void) { addVecVals<&vec1>();  };
};

void foo(void) {
    MISC<int> m;
    m.add();
}

Clang++ gives a somewhat better message:

/tmp/webcompile/_14512_0.cc:6:22: error: no matching member function for call
to 'addVecVals'
    void add(void) { addVecVals<&vec1>();  };
                     ^~~~~~~~~~~~~~~~~
/tmp/webcompile/_14512_0.cc:11:7: note: in instantiation of member function
'MISC<int>::add' requested here
    m.add();
      ^
/tmp/webcompile/_14512_0.cc:5:26: note: candidate template ignored: invalid
explicitly-specified argument for template parameter 'vc'
    template<T* vc> void addVecVals(){};
                         ^
1 error generated.


I would argue for reopening it...

[Bug c++/44906] g++ is giving error: parse error in template argument list while using a c++ code.

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44906

Paolo Carlini <paolo.carlini at oracle dot com> changed:

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

--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-23 12:43:53 UTC ---
Closing as invalid.