 --> [ local path prefix ]/port_instance/async_input_return_value.fpp:5:3
  |
5 |   async input port p: P
  |   ^^^^^^^^^^^^^^^^^^^^^ async input port may not return a value
  |
 ::: [ local path prefix ]/port_instance/async_input_return_value.fpp:1:6
  |
1 | port P -> U32
  |      - defined here

