V1013 worker_signature

@worker
fn double(n: Int) -> Int { n * 2 }

@worker
fn double(inbox: Inbox<Int>, outbox: Outbox<Int>) -> Unit ! {Worker} { … }

// Spec: https://html.spec.whatwg.org/multipage/workers.html#dom-worker

// `@worker` marks an entry a live worker starts by name with its two ports, so it sits on a
// non-generic `fn(Inbox<I>, Outbox<O>) -> Unit`; on anything else the entry could never be
// spawned and the attribute is reported where it is written. `fine` and `pure` are accepted:
// an entry may perform fewer effects than `Worker`.
import std/worker.{Inbox, Outbox, Worker}

@worker
fn fine(_inbox: Inbox<Int>, _outbox: Outbox<Int>) -> Unit ! {Worker} {}

@worker
fn pure(_inbox: Inbox<Int>, _outbox: Outbox<Int>) -> Unit {}

@worker
fn double(n: Int) -> Int { n * 2 }

@worker
fn swapped(_outbox: Outbox<Int>, _inbox: Inbox<Int>) -> Unit ! {Worker} {}

@worker
fn answers(_inbox: Inbox<Int>, _outbox: Outbox<Int>) -> Int ! {Worker} { 1 }

@worker
fn generic<T>(_inbox: Inbox<T>, _outbox: Outbox<T>) -> Unit ! {Worker} {}

@worker
type Job = { id: Int }

pub fn main() -> Unit { let _ = Job { id: 1 } }

{
  "schema_version": "1.0",
  "kind": "diagnostic",
  "id": "d:f0bed5a5af693094",
  "code": "V1013",
  "severity": "error",
  "phase": "resolve",
  "message": "`@worker` goes on a non-generic `fn(Inbox<I>, Outbox<O>) -> Unit`, any row: a worker is started by name with its two ports",
  "snapshot": "sha256:$SNAPSHOT",
  "symbol_id": "main::V1013_worker_signature::double",
  "spans": [
    {
      "uri": "file://$DIR/V1013_worker_signature.sak",
      "content_hash": "sha256:d2f2e95a690cc71eba6aa54403bd1dd1d3e202d0c98ddfb473977779a9c41e61",
      "start_byte": 751,
      "end_byte": 757,
      "role": "primary"
    }
  ],
  "related_ids": [],
  "expected": null,
  "actual": null,
  "obligation": null,
  "counterexample": null,
  "explanation_uri": "sakura://explain/V1013",
  "fixes": []
}