while trying to cut down the number of weak symbols exported by a shared library,
I came across a proposal  of yours to add an
__attribute__((__unique_instantiation__)) to clang that when placed on a
extern class template definition would allow the compiler to use strong symbols for that template instantiation instead of weak ones. I was wondering if you ever got around to implementing a prototype or whether your thinking has evolved on the matter. I think it would be quite a useful attribute to have.