on linux vps,"cargo build --release" encounter errors

[luckypoem]

hi.

on linux vps.
git clone https://github.com/bluejekyll/trust-dns/ trust-dns-by-bluejekyll
cd trust-dns-by-bluejekyll
cargo build --release
it shows:
...
Compiling tokio-sync v0.2.0-alpha.6
error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/barrier.rs:80:5
|
80 | / pub async fn wait(&self) -> BarrierWaitResult {
81 | | // NOTE: we are taking a synchronous lock here.
82 | | // It is okay to do so because the critical section is fast and never yields, so it cannot
83 | | // deadlock even if another future is concurrently holding the lock.
... |
118 | | BarrierWaitResult(false)
119 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/barrier.rs:113:16
|
113 | if wait.recv().await.expect("sender hasn't been closed") >= generation {
| ^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mpsc/bounded.rs:164:5
|
164 | / pub async fn recv(&mut self) -> Option {
165 | | use futures_util::future::poll_fn;
166 | |
167 | | poll_fn(|cx| self.poll_recv(cx)).await
168 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mpsc/bounded.rs:167:9
|
167 | poll_fn(|cx| self.poll_recv(cx)).await
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mpsc/bounded.rs:238:5
|
238 | / pub async fn send(&mut self, value: T) -> Result<(), SendError> {
239 | | use futures_util::future::poll_fn;
240 | |
241 | | poll_fn(|cx| self.poll_ready(cx)).await?;
242 | |
243 | | self.try_send(value).map_err(|_| SendError(()))
244 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mpsc/bounded.rs:241:9
|
241 | poll_fn(|cx| self.poll_ready(cx)).await?;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mpsc/unbounded.rs:134:5
|
134 | / pub async fn recv(&mut self) -> Option {
135 | | use futures_util::future::poll_fn;
136 | |
137 | | poll_fn(|cx| self.poll_recv(cx)).await
138 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mpsc/unbounded.rs:137:9
|
137 | poll_fn(|cx| self.poll_recv(cx)).await
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mutex.rs:87:5
|
87 | / pub async fn lock(&self) -> MutexGuard<'_, T> {
88 | | let mut permit = semaphore::Permit::new();
89 | | poll_fn(|cx| permit.poll_acquire(cx, &self.s))
90 | | .await
... |
97 | | MutexGuard { lock: self, permit }
98 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/mutex.rs:89:9
|
89 | / poll_fn(|cx| permit.poll_acquire(cx, &self.s))
90 | | .await
| |__________________^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/oneshot.rs:223:5
|
223 | / pub async fn closed(&mut self) {
224 | | use futures_util::future::poll_fn;
225 | |
226 | | poll_fn(|cx| self.poll_closed(cx)).await
227 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/oneshot.rs:226:9
|
226 | poll_fn(|cx| self.poll_closed(cx)).await
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/watch.rs:248:5
|
248 | / pub async fn recv_ref(&mut self) -> Option<Ref<'_, T>> {
249 | | let shared = &self.shared;
250 | | let inner = &self.inner;
251 | | let version = self.ver;
... |
259 | | }
260 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/watch.rs:253:15
|
253 | match poll_fn(|cx| poll_lock(cx, shared, inner, version)).await {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/watch.rs:295:5
|
295 | / pub async fn recv(&mut self) -> Option {
296 | | self.recv_ref().await.map(|v_ref| v_ref.clone())
297 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/watch.rs:296:9
|
296 | self.recv_ref().await.map(|v_ref| v_ref.clone())
| ^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async fn is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/watch.rs:386:5
|
386 | / pub async fn closed(&mut self) {
387 | | poll_fn(|cx| self.poll_close(cx)).await
388 | | }
| |_____^
|
= note: for more information, see rust-lang/rust#50547

error[E0658]: async/await is unstable
--> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.6/src/watch.rs:387:9
|
387 | poll_fn(|cx| self.poll_close(cx)).await
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, see rust-lang/rust#50547

error: aborting due to 18 previous errors

For more information about this error, try rustc --explain E0658.
error: Could not compile tokio-sync.
warning: build failed, waiting for other jobs to finish...
error: build failed

how to fix it?

[bluejekyll]

Which compiler version are you using? Master currently needs either 'beta' or 'nightly', until 1.39 is released to stable.

[luckypoem]

i see.
rustup install nightly
rustup default nightly
rustup update

then:
cargo build --release

that's done.