Output ports can not be used for further connects

When using an output port as a source of a connect statement, there will be no error or warning but no corresponding code will be generated.

This should either throw an error or just work. Could be helpful in situations like the following:

package ...;
component Test {
  port 
    in x,
    out y,
    out z;

  instance InstX instX;
  instance InstY instY;

  connect x -> instX.param;
  connect instX.res -> y;
  connect y -> instY.param; // this is the problematic line, one could of course also use instX.res again
  connect instY.res -> z;
}