It's my fault, I asked Ellidiss to release this constraint as I planned to give the possibility to expose SDL Procedures as kind of RPC - through sync PIs.
This is allowed by the SDL semantics.

However this is not yet properly implemented, the main issue is related to the code skeletons generation. It is not possible to "declare" the procedures in the part of the SDL function that is re-generated by taste-generate-skeletons (system_structure.pr) and let the user implement them inside the model part (contrary to normal SDL signals, which are declared and connected in one place, and used in another part)

I need to think more about it.

No problem, shall we close this ticket?

No, it is a bug, so let's keep it open until it is properly handled