[Bug c++/86392] templatized friend member function needs declaration

[rene.rahn@fu-berlin.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86392

--- Comment #1 from rene.rahn@fu-berlin.de ---
Created attachment 44347
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44347&action=edit
The example