[Rcpp-devel] slight gotcha in signature of constructors of classes to be exposed as Rcpp modules

I discovered that there is a difference between a constructor with the signature

  Foo(const NumericVector& ff);

and one with the signature

  Foo(NumericVector);

(other than the obvious differences in const'edness) if the class Foo
is to be exposed as an Rcpp module.  The second version works as
expected.  The first doesn't.  I imagine it has to do with the
argument disappearing going out of scope before the reference is used.
 Like Dirk, however, I feel that the innards of the module code are
above my pay grade and am only speculating.