[INFO] fetching crate plumbing 1.0.0...
[INFO] checking plumbing-1.0.0 against master#ceab6128fa48a616bfd3e3adf4bc80133b8ee223 for no-never-type-fallback
[INFO] extracting crate plumbing 1.0.0 into /workspace/builds/worker-6-tc1/source
[INFO] validating manifest of crates.io crate plumbing 1.0.0 on toolchain ceab6128fa48a616bfd3e3adf4bc80133b8ee223
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate plumbing 1.0.0
[INFO] finished tweaking crates.io crate plumbing 1.0.0
[INFO] tweaked toml for crates.io crate plumbing 1.0.0 written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 28 packages
[INFO] [stderr]       Adding bytes v0.5.6 (latest: v1.6.0)
[INFO] [stderr]       Adding pin-project-lite v0.1.12 (latest: v0.2.14)
[INFO] [stderr]       Adding syn v1.0.109 (latest: v2.0.58)
[INFO] [stderr]       Adding tokio v0.2.25 (latest: v1.37.0)
[INFO] [stderr]       Adding tokio-macros v0.2.6 (latest: v2.2.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded foreback v1.1.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 81e9010686f5a3b16731f42ffb0cc5c98ed76c70e5f032803ae3d6db15310467
[INFO] running `Command { std: "docker" "start" "-a" "81e9010686f5a3b16731f42ffb0cc5c98ed76c70e5f032803ae3d6db15310467", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "81e9010686f5a3b16731f42ffb0cc5c98ed76c70e5f032803ae3d6db15310467", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "81e9010686f5a3b16731f42ffb0cc5c98ed76c70e5f032803ae3d6db15310467", kill_on_drop: false }`
[INFO] [stdout] 81e9010686f5a3b16731f42ffb0cc5c98ed76c70e5f032803ae3d6db15310467
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3403367fc8bcf15002f7f277bddc6e3bb8fe40962cc72f4d4029fada71fb6748
[INFO] running `Command { std: "docker" "start" "-a" "3403367fc8bcf15002f7f277bddc6e3bb8fe40962cc72f4d4029fada71fb6748", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.79
[INFO] [stderr]    Compiling unicode-ident v1.0.12
[INFO] [stderr]    Compiling autocfg v1.2.0
[INFO] [stderr]     Checking futures-core v0.3.30
[INFO] [stderr]     Checking futures-sink v0.3.30
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling libc v0.2.153
[INFO] [stderr]     Checking pin-project-lite v0.2.14
[INFO] [stderr]     Checking futures-io v0.3.30
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]     Checking memchr v2.7.2
[INFO] [stderr]     Checking futures-channel v0.3.30
[INFO] [stderr]     Checking futures-task v0.3.30
[INFO] [stderr]     Checking bytes v0.5.6
[INFO] [stderr]     Checking pin-project-lite v0.1.12
[INFO] [stderr]    Compiling slab v0.4.9
[INFO] [stderr]     Checking futures-util v0.3.30
[INFO] [stderr]    Compiling quote v1.0.35
[INFO] [stderr]    Compiling syn v2.0.58
[INFO] [stderr]     Checking num_cpus v1.16.0
[INFO] [stderr]     Checking futures v0.3.30
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]    Compiling pin-project-internal v1.1.5
[INFO] [stderr]     Checking tokio v0.2.25
[INFO] [stderr]     Checking pin-project v1.1.5
[INFO] [stderr]     Checking foreback v1.1.2
[INFO] [stderr]     Checking plumbing v1.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the item `tokio` is imported redundantly
[INFO] [stdout]  --> tests/test.rs:7:13
[INFO] [stdout]   |
[INFO] [stdout] 7 | use tokio::{self, task};
[INFO] [stdout]   |             ^^^^ the item `tokio` is already defined by prelude
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused output of future returned by `tokio::task::yield_now` that must be used
[INFO] [stdout]   --> tests/test.rs:92:5
[INFO] [stdout]    |
[INFO] [stdout] 92 |     task::yield_now().await;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: yield_now does nothing unless polled/`await`-ed
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 92 |     let _ = task::yield_now().await;
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused output of future returned by `tokio::task::yield_now` that must be used
[INFO] [stdout]   --> tests/test.rs:93:5
[INFO] [stdout]    |
[INFO] [stdout] 93 |     task::yield_now().await;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: yield_now does nothing unless polled/`await`-ed
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 93 |     let _ = task::yield_now().await;
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.44s
[INFO] running `Command { std: "docker" "inspect" "3403367fc8bcf15002f7f277bddc6e3bb8fe40962cc72f4d4029fada71fb6748", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3403367fc8bcf15002f7f277bddc6e3bb8fe40962cc72f4d4029fada71fb6748", kill_on_drop: false }`
[INFO] [stdout] 3403367fc8bcf15002f7f277bddc6e3bb8fe40962cc72f4d4029fada71fb6748