The operator overloading page in the Language Reference and the
operator overloading discussion in TDLP say different things about
T opCast(bool)() if(is(T==bool))
and experimentally it seems that in any context where a bool is
expected and x occurs (where x is a struct with such an opCast
defined) then x will be rewritten as its conversion to bool using
that opCast.
Please confirm that the above is generally true or tell me the
exact rules.
Are there any other implicit conversions possible in D (apart
from int to long, int to double and so forth)?
