Assignment of continuous signals to discrete variables should be rejected

[Martin Sjölund]

Both of the following work, but should not:

class A
  Integer i = integer(time);
  discrete Real r = time;
end A;

Note that in a function, an assignment i := r; should still be allowed since in a function, all changes are discrete or continuous depending on your viewpoint. There probably will not be problems with inline functions since the variability of the call is simply the highest variability of the inputs.

(3.8 Variability of Expressions "If v is a discrete-time component then expr needs to be a discrete-time expression.")