[Bug c++/58022] Compiler rejects abstract class in template class with friend operator<<

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58022

--- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Please try to reduce the testcase further, no includes. You have a number of
options here: http://gcc.gnu.org/wiki/A_guide_to_testcase_reduction