https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67080
Bug ID: 67080 Summary: Access to private using declaration incorrectly allowed Product: gcc Version: 5.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: mwarusz at gmail dot com Target Milestone: --- Sample code: template <typename T> struct A { struct N { }; }; template <typename T> class B : public A<T> { using parent_t = A<T>; public: struct N : parent_t::N { }; }; template <typename T> void f() { typename B<T>::N n; // comment out for correct error typename B<T>::parent_t a; } int main() { f<int>(); } This compiles using g++ -std=c++11 even though parent_t is a private member of B. If the indicated line is commented out gcc correctly says that: bug.cpp: In instantiation of ‘void f() [with T = int]’: bug.cpp:25:10: required from here bug.cpp:10:24: error: ‘using parent_t = struct A<int>’ is private using parent_t = A<T>; ^ bug.cpp:20:27: error: within this context typename B<T>::parent_t a; Compiler details: Using built-in specs. COLLECT_GCC=g++ COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/5.2.0/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: /build/gcc/src/gcc-5.2.0/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --enable-libmpx --with-system-zlib --with-isl --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-lto --enable-plugin --enable-install-libiberty --with-linker-hash-style=gnu --enable-gnu-indirect-function --disable-multilib --disable-werror --enable-checking=release --with-default-libstdcxx-abi=gcc4-compatible Thread model: posix gcc version 5.2.0 (GCC)