[Bug c++/11664] New: Bad overload resolution in recursive template

[Bug c++/11664] New: Bad overload resolution in recursive template

[igodard at pacbell dot net]

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11664

           Summary: Bad overload resolution in recursive template
           Product: gcc
           Version: 3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: igodard at pacbell dot net
                CC: gcc-bugs at gcc dot gnu dot org

Source code below gives error, not finding the declaration for Bar(int). But if the unrelated definition of Bar() is commented out then it does find it. This may be an example of the "known" problem with two-step template resolution, but I don't understand that problem and so can't tell. Problem also occurs in 3.0.4 (at least). Here follows the output of g++ -v, followed by test case source:
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Reading specs from /usr/lib/gcc-lib/i686-pc-cygwin/3.2/specs
Configured with: /netrel/src/gcc-3.2-3/configure --enable-languages=c,c++,f77,java --enable-libgcj --enable-threads=posix --with-system-zlib --enable-nls --without-included-gettext --enable-interpreter --disable-sjlj-exceptions --disable-version-specific-runtime-libs --enable-shared --build=i686-pc-linux --host=i686-pc-cygwin --target=i686-pc-cygwin --enable-haifa --prefix=/usr --exec-prefix=/usr --sysconfdir=/etc --libdir=/usr/lib --includedir=/nonexistent/include --libexecdir=/usr/sbin
Thread model: posix
gcc version 3.2 20020927 (prerelease)
 /usr/lib/gcc-lib/i686-pc-cygwin/3.2/cpp0.exe -lang-c++ -D__GNUG__=3 -D__DEPRECATED -D__EXCEPTIONS -v -D__GNUC__=3 -D__GNUC_MINOR__=2 -D__GNUC_PATCHLEVEL__=0 -D__GXX_ABI_VERSION=102 -D_X86_=1 -D_X86_=1 -Asystem=winnt -D__NO_INLINE__ -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386__ -D__tune_i686__ -D__tune_pentiumpro__ -D__tune_pentium2__ -D__tune_pentium3__ -D__stdcall=__attribute__((__stdcall__)) -D__fastcall=__attribute__((__fastcall__)) -D__cdecl=__attribute__((__cdecl__)) -D_stdcall=__attribute__((__stdcall__)) -D_fastcall=__attribute__((__fastcall__)) -D_cdecl=__attribute__((__cdecl__)) -D__declspec(x)=__attribute__((x)) -D__i386__ -D__i386 -D__CYGWIN32__ -D__CYGWIN__ -Dunix -D__unix__ -D__unix -isystem ../include/w32api -isystem ../../include/w32api tst.cc tst.ii
ignoring nonexistent directory "../include/w32api"
ignoring nonexistent directory "../../include/w32api"
GNU CPP version 3.2 20020927 (prerelease) (cpplib) (80386, BSD syntax)
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/usr/i686-pc-cygwin/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/c++/3.2
 /usr/include/c++/3.2/i686-pc-cygwin
 /usr/include/c++/3.2/backward
 /usr/lib/gcc-lib/i686-pc-cygwin/3.2/include
 /usr/include
End of search list.
 /usr/lib/gcc-lib/i686-pc-cygwin/3.2/cc1plus.exe -fpreprocessed tst.ii -quiet -dumpbase tst.cc -version -o tst.s
GNU CPP version 3.2 20020927 (prerelease) (cpplib) (80386, BSD syntax)
GNU C++ version 3.2 20020927 (prerelease) (i686-pc-cygwin)
	compiled by GNU C version 3.2 20020927 (prerelease).
tst.cc: In function `int main()':
tst.cc:22: no matching function for call to `T::Bar(int)'
tst.cc:13: candidates are: void T::Bar()
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
class Bottom {};
template<typename Super, typename Sub = Bottom>
class Mixin : Sub {
	Super*	AsSuper() { return static_cast<Super*>(this); }
public:
	void	Bar(int i) { AsSuper()->Foo(i); }
	};

class T : public Mixin<T> {
public:
	void	Foo(int i) {}
	void	Foo() {}
	void	Bar() {}
	int i;
	};



int main() {
	T t;
	t.Bar();
	t.Bar(1);
	t.Foo();
	t.Foo(1);
	}

[Bug c++/11664] Bad overload resolution in recursive template

[igodard at pacbell dot net]

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11664



------- Additional Comments From igodard at pacbell dot net  2003-07-24 20:47 -------
Created an attachment (id=4476)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=4476&action=view)
tst.cc - test case displaying bug

[Bug c++/11664] Bad overload resolution in recursive template

[bangerth at dealii dot org]

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11664


bangerth at dealii dot org changed:

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


------- Additional Comments From bangerth at dealii dot org  2003-07-24 21:55 -------
This is not a bug: the declaration of the function in the derived class
hides the one in the base class. You can either use a using-declaration
in the derived class like
  class T : public Mixin<T> {
  public:
    Mixin<T>::Bar;
    void	Foo(int i) {}
    void	Foo() {}
    void	Bar() {}
    int i;
  };
or qualify the use of the function:
  t.Mixin<T>::Bar(1);

W.