[Bug c++/58170] New: Crash when aliasing a template class that is a member of its template base class.

["cassio.neri at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58170

            Bug ID: 58170
           Summary: Crash when aliasing a template class that is a member
                    of its template base class.
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: cassio.neri at gmail dot com

The code below crashes gcc 4.8.1 (coincidentaly, it also crashes clang 3.3).

---------------------------------------------------------------------

template <typename T, typename U>
struct base {

  template <typename V>
  struct derived;

};

template <typename T, typename U>
template <typename V>
struct base<T, U>::derived : public base<T, V> {
};

// This (wrong?) alias declaration provoques the crash.
template <typename T, typename U, typename V>
using derived = base<T, U>::derived<V>;

// This one works:
// template <typename T, typename U, typename V>
// using derived = typename base<T, U>::template derived<V>;

template <typename T>
void f() {
  derived<T, bool, char> m{};
  (void) m;
}

int main() {
  f<int>();
}

---------------------------------------------------------------------

$ g++ -v -save-temps -std=c++11 -Wall -pedantic main.cpp 
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /build/gcc/src/gcc-4.8-20130725/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 --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch
--enable-gnu-unique-object --enable-linker-build-id --enable-cloog-backend=isl
--disable-cloog-version-check --enable-lto --enable-gold --enable-ld=default
--enable-plugin --with-plugin-ld=ld.gold --with-linker-hash-style=gnu
--disable-install-libiberty --disable-multilib --disable-libssp
--disable-werror --enable-checking=release
Thread model: posix
gcc version 4.8.1 20130725 (prerelease) (GCC) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++11' '-Wall' '-Wpedantic'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
 /usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/cc1plus -E -quiet -v -D_GNU_SOURCE
main.cpp -mtune=generic -march=x86-64 -std=c++11 -Wall -Wpedantic
-fpch-preprocess -o main.ii
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../include/c++/4.8.1

/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../include/c++/4.8.1/x86_64-unknown-linux-gnu

/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../include/c++/4.8.1/backward
 /usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/include
 /usr/local/include
 /usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++11' '-Wall' '-Wpedantic'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
 /usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/cc1plus -fpreprocessed main.ii
-quiet -dumpbase main.cpp -mtune=generic -march=x86-64 -auxbase main -Wall
-Wpedantic -std=c++11 -version -o main.s
GNU C++ (GCC) version 4.8.1 20130725 (prerelease) (x86_64-unknown-linux-gnu)
        compiled by GNU C version 4.8.1 20130725 (prerelease), GMP version
5.1.2, MPFR version 3.1.2, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++ (GCC) version 4.8.1 20130725 (prerelease) (x86_64-unknown-linux-gnu)
        compiled by GNU C version 4.8.1 20130725 (prerelease), GMP version
5.1.2, MPFR version 3.1.2, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: fcec9480bd3d120c7e8d40d79394317d
main.cpp: In substitution of âtemplate<class T, class U, class V> using derived
= base<T, U>::derived<V> [with T = T; U = bool; V = char]â:
main.cpp:24:24:   required from here
main.cpp:16:39: internal compiler error: Segmentation fault
 using derived = base<T, U>::derived<V>;
                                       ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.archlinux.org/> for instructions.