[Bug c++/68186] New: Using public base member function privately prevents derived classes using base member function

[jwyatt at feralinteractive dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68186

            Bug ID: 68186
           Summary: Using public base member function privately prevents
                    derived classes using base member function
           Product: gcc
           Version: 5.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jwyatt at feralinteractive dot com
  Target Milestone: ---

Created attachment 36637
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36637&action=edit
Minimal example

The following setup (compiled with g++ -Wall -Wextra) causes the error:

‘int Base::Method()’ is inaccessible

within the Derived2 context. This doesn't happen if the using statement within
the class Derived is removed, or if it is made public.

class Base
{
public:
    int Method();
};

class Derived : public Base
{
    using Base::Method;
};

class Derived2 : public Derived
{
    using Base::Method;
};

g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/5.1.1/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --enable-bootstrap
--enable-languages=c,c++,objc,obj-c++,fortran,ada,go,lto --prefix=/usr
--mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared
--enable-threads=posix --enable-checking=release --enable-multilib
--with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions
--enable-gnu-unique-object --enable-linker-build-id
--with-linker-hash-style=gnu --enable-plugin --enable-initfini-array
--disable-libgcj --with-default-libstdcxx-abi=c++98 --with-isl --enable-libmpx
--enable-gnu-indirect-function --with-tune=generic --with-arch_32=i686
--build=x86_64-redhat-linux
Thread model: posix
gcc version 5.1.1 20150618 (Red Hat 5.1.1-4) (GCC)