  --> [ local path prefix ]/connection_direct/typed_to_serial_with_return.fpp:14:5
   |
14 |     c1.pOut -> c2.serialIn
   |     ^^^^^^^ cannot connect output port of type P, which returns a value, to serial input port
   |
  ::: [ local path prefix ]/connection_direct/typed_to_serial_with_return.fpp:3:3
   |
 3 |   output port pOut: P
   |   ------------------- from port is specified here
   |
  ::: [ local path prefix ]/connection_direct/typed_to_serial_with_return.fpp:6:3
   |
 6 |   sync input port serialIn: serial
   |   -------------------------------- to port is specified here
   |
  ::: [ local path prefix ]/connection_direct/typed_to_serial_with_return.fpp:1:1
   |
 1 | port P -> U32
   | ------------- from port type is defined here

