[Bug c++/40664] New: Parse error declaring friend class using dependent template instance

trevor at scurrilous dot com gcc-bugzilla@gcc.gnu.org
Mon Jul 6 19:43:00 GMT 2009


The following code fails to compile on GCC 4.3.3. It compiles on Intel C++ 11.1
and Comeau 4.3.10.1.

g++ -v -save-temps main.cpp

Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.3.3-5ubuntu4'
--with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3
--program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug
--enable-objc-gc --enable-mpfr --with-tune=generic --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-shared-libgcc' '-mtune=generic'
 /usr/lib/gcc/x86_64-linux-gnu/4.3.3/cc1plus -E -quiet -v -D_GNU_SOURCE
main.cpp -D_FORTIFY_SOURCE=2 -mtune=generic -fpch-preprocess -o main.ii
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/4.3.3/../../../../x86_64-linux-gnu/include"
ignoring nonexistent directory "/usr/include/x86_64-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/c++/4.3
 /usr/include/c++/4.3/x86_64-linux-gnu
 /usr/include/c++/4.3/backward
 /usr/local/include
 /usr/lib/gcc/x86_64-linux-gnu/4.3.3/include
 /usr/lib/gcc/x86_64-linux-gnu/4.3.3/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-shared-libgcc' '-mtune=generic'
 /usr/lib/gcc/x86_64-linux-gnu/4.3.3/cc1plus -fpreprocessed main.ii -quiet
-dumpbase main.cpp -mtune=generic -auxbase main -version -fstack-protector -o
main.s
GNU C++ (Ubuntu 4.3.3-5ubuntu4) version 4.3.3 (x86_64-linux-gnu)
        compiled by GNU C version 4.3.3, GMP version 4.2.4, MPFR version 2.4.0.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: d9dd67dcc191271ac69fd2c05266cf9c
main.cpp:22: error: expected identifier before ‘;’ token
main.cpp:22: error: friend declaration does not name a class or function
main.cpp: In member function ‘T Base<T>::InnerBase<D>::baseImpl() [with D =
Derived<int>::InnerDerived, T = int]Â’:
main.cpp:27:   instantiated from ‘T Derived<T>::InnerDerived::operation() [with
T = int]Â’
main.cpp:45:   instantiated from here
main.cpp:31: error: ‘T Derived<T>::InnerDerived::derivedHelper() [with T =
int]Â’ is private
main.cpp:11: error: within this context

main.cpp:

template <class T>
class Base
{
protected:
    template <class D>
    class InnerBase
    {
    protected:
        T baseImpl()
        {
            return static_cast<D*>(this)->derivedHelper();
        }
    };
};

template <class T>
class Derived : public Base<T>
{
public:
    class InnerDerived : public Base<T>::template InnerBase<InnerDerived>
    {
        friend class Base<T>::template InnerBase<InnerDerived>; // <--- error:
expected identifier before ‘;’ token

    public:
        T operation()
        {
            return this->baseImpl();
        }

    private:
        T derivedHelper()
        {
            return T(42);
        }
    };

    InnerDerived makeInner() const
    {
        return InnerDerived();
    }
};

int main(int argc, char* argv[])
{
    return Derived<int>().makeInner().operation();
}


-- 
           Summary: Parse error declaring friend class using dependent
                    template instance
           Product: gcc
           Version: 4.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: trevor at scurrilous dot com
 GCC build triplet: x86_64-linux-gnu
  GCC host triplet: x86_64-linux-gnu
GCC target triplet: x86_64-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40664



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