boostorg/spirit — pull request #36 by sehe (2014-06-06 00:14:17+00:00)
Title: Fix assignment basic_hold_any::operator= #35 (c++11)

The template version would not be used because the compiler-generated
one was a closer match. The implicit assignment, however, broke the
ownership semantics.

See also Pull Request #35 (wrong branch, not C++11 safe)