IssueTracker

The C++ reference for assignment operators states that "All built-in assignment operators return *this, and most user-defined overloads also return *this so that the user-defined operators can be used in the same manner as the built-ins."

Reactor should follow suite to support expressions like a = b = c and avoid "surprises" that differ from C++'s behavior.

See also https://clang.llvm.org/extra/clang-tidy/checks/misc-unconventional-assign-operator.html.