#[task] 的报错：非 'static、泛型、impl Trait、17 个参数

#[embassy_executor::task]
async fn log_line(prefix: &str, buf: &mut [u8; 64]) { /* ... */ }

error: Arguments for tasks must live forever. Try using the `'static` lifetime.
 --> src/bin/mac_nonstatic.rs:4:27
  |
4 | async fn log_line(prefix: &str, buf: &mut [u8; 64]) {
  |                           ^

error: Arguments for tasks must live forever. Try using the `'static` lifetime.
 --> src/bin/mac_nonstatic.rs:4:38

error: task functions must not be generic
 --> src/bin/mac_generic.rs:8:1
  |
8 | async fn poll_sensor<S: Sensor + 'static>(mut s: S) {
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: `impl Trait` is not allowed in task arguments. It is syntax sugar for generics, and tasks can't be generic.
 --> src/bin/mac_impl.rs:8:29
  |
8 | async fn poll_sensor(mut s: impl Sensor + 'static) {
  |                             ^^^^^^^^^^^^^^^^^^^^^

#[embassy_executor::task]
async fn blink(_led: Led<'_>) {}

#[embassy_executor::task]
async fn blink2(_led: Led) {}

error: Arguments for tasks must live forever. Try using the `'static` lifetime.
 --> src/bin/mac_elided.rs:9:26
  |
9 | async fn blink(_led: Led<'_>) {}
  |                          ^^

error[E0726]: implicit elided lifetime not allowed here
  --> src/bin/mac_elided.rs:12:23
   |
12 | async fn blink2(_led: Led) {}
   |                       ^^^ expected lifetime parameter
...
error: lifetime may not live long enough
  --> src/bin/mac_elided.rs:11:1
   |
11 | #[embassy_executor::task]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static`
12 | async fn blink2(_led: Led) {}
   |                 ---- has type `Led<'1>`
   |
   = note: this error originates in the attribute macro `embassy_executor::task` (in Nightly builds, run with -Z macro-backtrace for more info)
help: to declare that `impl Sized` captures data from argument `_led`, you can add an explicit `'_` lifetime bound
   |
11 | #[embassy_executor::task] + '_
   |                           ++++

error[E0277]: task futures must resolve to `()` or `!`
   --> src/bin/mac_args17.rs:4:10
    |
  3 | #[embassy_executor::task]
    | ------------------------- required by a bound introduced by this call
  4 | async fn many(a0: u8, a1: u8, a2: u8, a3: u8, a4: u8, a5: u8, a6: u8, a7: u8, a8: u8,
    |          ^^^^ unsatisfied trait bound
    |
    = help: the trait `embassy_executor::_export::TaskFn<_>` is not implemented for fn item `fn(u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8) -> _ {__many_task}`
    = note: use `async fn` or change the return type to `impl Future<Output = ()>`
...
error: could not compile `pita-std` (bin "mac_args17") due to 7 previous errors

        fn visit_type_reference(&mut self, i: &'ast syn::TypeReference) {
            // Only check for elided lifetime here. If not elided, it's checked by `visit_lifetime`.
            if i.lifetime.is_none() {
                error(
                    self.errors,
                    i.and_token,
                    "Arguments for tasks must live forever. Try using the `'static` lifetime.",
                )
            }
            visit::visit_type_reference(self, i);
        }

        fn visit_lifetime(&mut self, i: &'ast syn::Lifetime) {
            if i.ident.to_string() != "static" {
                // ... same error
            }
        }

// 1. borrowed arguments: make them 'static (a string literal, a StaticCell)
#[embassy_executor::task]
async fn log_line(prefix: &'static str, buf: &'static mut [u8; 64]) { /* ... */ }

// 2. generic / impl Trait: a trait object behind a 'static reference
#[embassy_executor::task]
async fn poll_sensor(s: &'static mut dyn Sensor) { /* ... */ }

// 3. generic, keeping static dispatch: one small task per concrete type
async fn poll_generic<S: Sensor>(mut s: S) { /* ... */ }
#[embassy_executor::task]
async fn poll_thermo(s: Thermo) {
  poll_generic(s).await
}

// 4. more than 16 arguments: one struct
struct Config {
  pins: [u8; 17],
}
#[embassy_executor::task]
async fn many(cfg: Config) { /* ... */ }

static BUF: StaticCell<[u8; 64]> = StaticCell::new();
static THERMO: StaticCell<Thermo> = StaticCell::new();

// in main:
spawner.spawn(log_line("line", BUF.init([0; 64])).unwrap());
spawner.spawn(poll_sensor(THERMO.init(Thermo(20))).unwrap());
spawner.spawn(poll_thermo(Thermo(30)).unwrap());
spawner.spawn(many(Config { pins: [0; 17] }).unwrap());

pins 17
generic 31
sensor 21
line 1