[INFO] fetching crate tangle 0.4.0...
[INFO] checking tangle-0.4.0 against master#9610dfe5a9a731ced1ea4923ecbd0c57fe367898 for beta-170-4
[INFO] extracting crate tangle 0.4.0 into /workspace/builds/worker-1-tc1/source
[INFO] validating manifest of crates.io crate tangle 0.4.0 on toolchain 9610dfe5a9a731ced1ea4923ecbd0c57fe367898
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9610dfe5a9a731ced1ea4923ecbd0c57fe367898" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate tangle 0.4.0
[INFO] finished tweaking crates.io crate tangle 0.4.0
[INFO] tweaked toml for crates.io crate tangle 0.4.0 written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" __CARGO_TEST_CHANNEL_OVERRIDE_DO_NOT_USE_THIS="nightly" "/workspace/cargo-home/bin/cargo" "+9610dfe5a9a731ced1ea4923ecbd0c57fe367898" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9610dfe5a9a731ced1ea4923ecbd0c57fe367898" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded lazy_static v0.1.16
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:19e73879b68f455e41552ea35293514db52ea292d993f571636dbffedb77a1ee" "/opt/rustwide/cargo-home/bin/cargo" "+9610dfe5a9a731ced1ea4923ecbd0c57fe367898" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 93bf7538bef25f4c17891c766d6076b8843ac2673db67ec296d244da9d7c0421
[INFO] running `Command { std: "docker" "start" "-a" "93bf7538bef25f4c17891c766d6076b8843ac2673db67ec296d244da9d7c0421", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "93bf7538bef25f4c17891c766d6076b8843ac2673db67ec296d244da9d7c0421", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "93bf7538bef25f4c17891c766d6076b8843ac2673db67ec296d244da9d7c0421", kill_on_drop: false }`
[INFO] [stdout] 93bf7538bef25f4c17891c766d6076b8843ac2673db67ec296d244da9d7c0421
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:19e73879b68f455e41552ea35293514db52ea292d993f571636dbffedb77a1ee" "/opt/rustwide/cargo-home/bin/cargo" "+9610dfe5a9a731ced1ea4923ecbd0c57fe367898" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 32b51bdd4ebfbc120f346557fa4368760a0aa170be0d938a69ee8dbdcebdd805
[INFO] running `Command { std: "docker" "start" "-a" "32b51bdd4ebfbc120f346557fa4368760a0aa170be0d938a69ee8dbdcebdd805", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.144
[INFO] [stderr]     Checking lazy_static v0.1.16
[INFO] [stderr]     Checking num_cpus v1.15.0
[INFO] [stderr]     Checking num_cpus v0.2.13
[INFO] [stderr]     Checking threadpool v1.8.1
[INFO] [stderr]     Checking tangle v0.4.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::thread`
[INFO] [stdout]  --> src/lib.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::thread;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::convert`
[INFO] [stdout]   --> src/lib.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::convert;
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::thread`
[INFO] [stdout]  --> src/lib.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::thread;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::convert`
[INFO] [stdout]   --> src/lib.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::convert;
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Receiver`, `Sender`
[INFO] [stdout]    --> src/lib.rs:368:36
[INFO] [stdout]     |
[INFO] [stdout] 368 |     use std::sync::mpsc::{channel, Receiver, Sender};
[INFO] [stdout]     |                                    ^^^^^^^^  ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated constant `std::sync::ONCE_INIT`: the `new` function is now preferred
[INFO] [stdout]   --> src/lib.rs:21:1
[INFO] [stdout]    |
[INFO] [stdout] 21 | / lazy_static! {
[INFO] [stdout] 22 | |     static ref POOL: Mutex<ThreadPool> = Mutex::new(ThreadPool::new(num_cpus::get()));
[INFO] [stdout] 23 | | }
[INFO] [stdout]    | |_^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(deprecated)]` on by default
[INFO] [stdout]    = note: this warning originates in the macro `lazy_static` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated constant `std::sync::ONCE_INIT`: the `new` function is now preferred
[INFO] [stdout]   --> src/lib.rs:21:1
[INFO] [stdout]    |
[INFO] [stdout] 21 | / lazy_static! {
[INFO] [stdout] 22 | |     static ref POOL: Mutex<ThreadPool> = Mutex::new(ThreadPool::new(num_cpus::get()));
[INFO] [stdout] 23 | | }
[INFO] [stdout]    | |_^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this warning originates in the macro `lazy_static` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
[INFO] [stdout]    --> src/lib.rs:178:9
[INFO] [stdout]     |
[INFO] [stdout] 178 | impl<T, E=()> Future<T, E>
[INFO] [stdout]     |         ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stdout]     = note: for more information, see issue #36887 <https://github.com/rust-lang/rust/issues/36887>
[INFO] [stdout]     = note: `#[deny(invalid_type_param_default)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated constant `std::sync::ONCE_INIT`: the `new` function is now preferred
[INFO] [stdout]   --> src/lib.rs:21:1
[INFO] [stdout]    |
[INFO] [stdout] 21 | / lazy_static! {
[INFO] [stdout] 22 | |     static ref POOL: Mutex<ThreadPool> = Mutex::new(ThreadPool::new(num_cpus::get()));
[INFO] [stdout] 23 | | }
[INFO] [stdout]    | |_^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(deprecated)]` on by default
[INFO] [stdout]    = note: this warning originates in the macro `lazy_static` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated constant `std::sync::ONCE_INIT`: the `new` function is now preferred
[INFO] [stdout]   --> src/lib.rs:21:1
[INFO] [stdout]    |
[INFO] [stdout] 21 | / lazy_static! {
[INFO] [stdout] 22 | |     static ref POOL: Mutex<ThreadPool> = Mutex::new(ThreadPool::new(num_cpus::get()));
[INFO] [stdout] 23 | | }
[INFO] [stdout]    | |_^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this warning originates in the macro `lazy_static` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
[INFO] [stdout]    --> src/lib.rs:178:9
[INFO] [stdout]     |
[INFO] [stdout] 178 | impl<T, E=()> Future<T, E>
[INFO] [stdout]     |         ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stdout]     = note: for more information, see issue #36887 <https://github.com/rust-lang/rust/issues/36887>
[INFO] [stdout]     = note: `#[deny(invalid_type_param_default)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cont`
[INFO] [stdout]   --> src/lib.rs:46:29
[INFO] [stdout]    |
[INFO] [stdout] 46 |             Async::Continue(cont) => panic!("Cannot map on `Async::Continue`. Use `map_future` for that.")
[INFO] [stdout]    |                             ^^^^ help: if this is intentional, prefix it with an underscore: `_cont`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cont`
[INFO] [stdout]   --> src/lib.rs:54:29
[INFO] [stdout]    |
[INFO] [stdout] 54 |             Async::Continue(cont) => panic!("Cannot map on `Async::Continue`. Use `map_future` for that.")
[INFO] [stdout]    |                             ^^^^ help: if this is intentional, prefix it with an underscore: `_cont`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `chan` and `state` are never read
[INFO] [stdout]    --> src/lib.rs:136:5
[INFO] [stdout]     |
[INFO] [stdout] 135 | pub struct Promise<T, E=()> {
[INFO] [stdout]     |            ------- fields in this struct
[INFO] [stdout] 136 |     chan: Sender<Async<T, E>>,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 137 |     rx: Option<Receiver<Async<T, E>>>,
[INFO] [stdout] 138 |     state: PromiseState
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `Promise` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `read` is never read
[INFO] [stdout]    --> src/lib.rs:175:5
[INFO] [stdout]     |
[INFO] [stdout] 173 | pub struct Future<T, E=()> {
[INFO] [stdout]     |            ------ field in this struct
[INFO] [stdout] 174 |     receiver: Receiver<Async<T, E>>,
[INFO] [stdout] 175 |     read: bool
[INFO] [stdout]     |     ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `Future` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cont`
[INFO] [stdout]   --> src/lib.rs:46:29
[INFO] [stdout]    |
[INFO] [stdout] 46 |             Async::Continue(cont) => panic!("Cannot map on `Async::Continue`. Use `map_future` for that.")
[INFO] [stdout]    |                             ^^^^ help: if this is intentional, prefix it with an underscore: `_cont`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cont`
[INFO] [stdout]   --> src/lib.rs:54:29
[INFO] [stdout]    |
[INFO] [stdout] 54 |             Async::Continue(cont) => panic!("Cannot map on `Async::Continue`. Use `map_future` for that.")
[INFO] [stdout]    |                             ^^^^ help: if this is intentional, prefix it with an underscore: `_cont`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:192:48
[INFO] [stdout]     |
[INFO] [stdout] 192 |         POOL.lock().unwrap().execute(move || { tx.send(f()); });
[INFO] [stdout]     |                                                ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 192 |         POOL.lock().unwrap().execute(move || { let _ = tx.send(f()); });
[INFO] [stdout]     |                                                +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:274:30
[INFO] [stdout]     |
[INFO] [stdout] 274 |                 Ok(val) => { tx.send(f(val)); },
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 274 |                 Ok(val) => { let _ = tx.send(f(val)); },
[INFO] [stdout]     |                              +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:275:31
[INFO] [stdout]     |
[INFO] [stdout] 275 |                 Err(err) => { tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 275 |                 Err(err) => { let _ = tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:305:30
[INFO] [stdout]     |
[INFO] [stdout] 305 |                 Ok(val) => { tx.send(Async::Ok(f(val))); },
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 305 |                 Ok(val) => { let _ = tx.send(Async::Ok(f(val))); },
[INFO] [stdout]     |                              +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:306:31
[INFO] [stdout]     |
[INFO] [stdout] 306 |                 Err(err) => { tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 306 |                 Err(err) => { let _ = tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:338:9
[INFO] [stdout]     |
[INFO] [stdout] 338 |         tx.send(Async::Ok(val));
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 338 |         let _ = tx.send(Async::Ok(val));
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:354:9
[INFO] [stdout]     |
[INFO] [stdout] 354 |         tx.send(Async::Err(err));
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 354 |         let _ = tx.send(Async::Err(err));
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 15 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]    --> src/lib.rs:386:17
[INFO] [stdout]     |
[INFO] [stdout] 386 |             let v = async!(v);
[INFO] [stdout]     |                 ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `tangle` (lib) due to 2 previous errors; 15 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `err`
[INFO] [stdout]    --> src/lib.rs:429:17
[INFO] [stdout]     |
[INFO] [stdout] 429 |             Err(err) => panic!("Unexpected case.")
[INFO] [stdout]     |                 ^^^ help: if this is intentional, prefix it with an underscore: `_err`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `err`
[INFO] [stdout]    --> src/lib.rs:478:17
[INFO] [stdout]     |
[INFO] [stdout] 478 |             Err(err) => panic!("Unexpected value")
[INFO] [stdout]     |                 ^^^ help: if this is intentional, prefix it with an underscore: `_err`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `err`
[INFO] [stdout]    --> src/lib.rs:488:17
[INFO] [stdout]     |
[INFO] [stdout] 488 |             Err(err) => panic!("Unexpected value")
[INFO] [stdout]     |                 ^^^ help: if this is intentional, prefix it with an underscore: `_err`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `err`
[INFO] [stdout]    --> src/lib.rs:504:17
[INFO] [stdout]     |
[INFO] [stdout] 504 |             Err(err) => panic!("Unexpected value")
[INFO] [stdout]     |                 ^^^ help: if this is intentional, prefix it with an underscore: `_err`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `n`
[INFO] [stdout]    --> src/lib.rs:496:51
[INFO] [stdout]     |
[INFO] [stdout] 496 |         let curr: Future<usize> = count.and_then(|n| {
[INFO] [stdout]     |                                                   ^ help: if this is intentional, prefix it with an underscore: `_n`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `chan` and `state` are never read
[INFO] [stdout]    --> src/lib.rs:136:5
[INFO] [stdout]     |
[INFO] [stdout] 135 | pub struct Promise<T, E=()> {
[INFO] [stdout]     |            ------- fields in this struct
[INFO] [stdout] 136 |     chan: Sender<Async<T, E>>,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 137 |     rx: Option<Receiver<Async<T, E>>>,
[INFO] [stdout] 138 |     state: PromiseState
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `Promise` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `read` is never read
[INFO] [stdout]    --> src/lib.rs:175:5
[INFO] [stdout]     |
[INFO] [stdout] 173 | pub struct Future<T, E=()> {
[INFO] [stdout]     |            ------ field in this struct
[INFO] [stdout] 174 |     receiver: Receiver<Async<T, E>>,
[INFO] [stdout] 175 |     read: bool
[INFO] [stdout]     |     ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `Future` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:192:48
[INFO] [stdout]     |
[INFO] [stdout] 192 |         POOL.lock().unwrap().execute(move || { tx.send(f()); });
[INFO] [stdout]     |                                                ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 192 |         POOL.lock().unwrap().execute(move || { let _ = tx.send(f()); });
[INFO] [stdout]     |                                                +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:274:30
[INFO] [stdout]     |
[INFO] [stdout] 274 |                 Ok(val) => { tx.send(f(val)); },
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 274 |                 Ok(val) => { let _ = tx.send(f(val)); },
[INFO] [stdout]     |                              +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:275:31
[INFO] [stdout]     |
[INFO] [stdout] 275 |                 Err(err) => { tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 275 |                 Err(err) => { let _ = tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:305:30
[INFO] [stdout]     |
[INFO] [stdout] 305 |                 Ok(val) => { tx.send(Async::Ok(f(val))); },
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 305 |                 Ok(val) => { let _ = tx.send(Async::Ok(f(val))); },
[INFO] [stdout]     |                              +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:306:31
[INFO] [stdout]     |
[INFO] [stdout] 306 |                 Err(err) => { tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 306 |                 Err(err) => { let _ = tx.send(Async::Err(err)); }
[INFO] [stdout]     |                               +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:338:9
[INFO] [stdout]     |
[INFO] [stdout] 338 |         tx.send(Async::Ok(val));
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 338 |         let _ = tx.send(Async::Ok(val));
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:354:9
[INFO] [stdout]     |
[INFO] [stdout] 354 |         tx.send(Async::Err(err));
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 354 |         let _ = tx.send(Async::Err(err));
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:425:9
[INFO] [stdout]     |
[INFO] [stdout] 425 |         tx.send(123);
[INFO] [stdout]     |         ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 425 |         let _ = tx.send(123);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:447:9
[INFO] [stdout]     |
[INFO] [stdout] 447 |         tx.send(555);
[INFO] [stdout]     |         ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 447 |         let _ = tx.send(555);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 24 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `tangle` (lib test) due to 2 previous errors; 24 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "32b51bdd4ebfbc120f346557fa4368760a0aa170be0d938a69ee8dbdcebdd805", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "32b51bdd4ebfbc120f346557fa4368760a0aa170be0d938a69ee8dbdcebdd805", kill_on_drop: false }`
[INFO] [stdout] 32b51bdd4ebfbc120f346557fa4368760a0aa170be0d938a69ee8dbdcebdd805
