[INFO] fetching crate ssh-muxcontrol 0.1.0...
[INFO] checking ssh-muxcontrol-0.1.0 against master#385fa9d845dd326c6bbfd58c22244215e431948a for never-type-fallback-to-never
[INFO] extracting crate ssh-muxcontrol 0.1.0 into /workspace/builds/worker-4-tc1/source
[INFO] validating manifest of crates.io crate ssh-muxcontrol 0.1.0 on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate ssh-muxcontrol 0.1.0
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate ssh-muxcontrol 0.1.0
[INFO] tweaked toml for crates.io crate ssh-muxcontrol 0.1.0 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] crate crates.io crate ssh-muxcontrol 0.1.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded tokio-macros v1.5.0
[INFO] [stderr]   Downloaded tokio-pipe v0.2.1
[INFO] [stderr]   Downloaded sendfd v0.4.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 95fd61c5e39ecde6497075dcea4d1e3b55bc83eea3b5674c967fe3e22e38ca3d
[INFO] running `Command { std: "docker" "start" "-a" "95fd61c5e39ecde6497075dcea4d1e3b55bc83eea3b5674c967fe3e22e38ca3d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "95fd61c5e39ecde6497075dcea4d1e3b55bc83eea3b5674c967fe3e22e38ca3d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "95fd61c5e39ecde6497075dcea4d1e3b55bc83eea3b5674c967fe3e22e38ca3d", kill_on_drop: false }`
[INFO] [stdout] 95fd61c5e39ecde6497075dcea4d1e3b55bc83eea3b5674c967fe3e22e38ca3d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b612e9c8e74d9981f174eaf8c11470a1f279b898f669409ce1bf4cca3b8dd871
[INFO] running `Command { std: "docker" "start" "-a" "b612e9c8e74d9981f174eaf8c11470a1f279b898f669409ce1bf4cca3b8dd871", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.30
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]    Compiling syn v1.0.80
[INFO] [stderr]    Compiling libc v0.2.104
[INFO] [stderr]     Checking pin-project-lite v0.2.7
[INFO] [stderr]     Checking bytes v1.1.0
[INFO] [stderr]    Compiling tokio v1.12.0
[INFO] [stderr]    Compiling quote v1.0.10
[INFO] [stderr]     Checking mio v0.7.14
[INFO] [stderr]    Compiling tokio-macros v1.5.0
[INFO] [stderr]     Checking tokio-pipe v0.2.1
[INFO] [stderr]     Checking sendfd v0.4.0
[INFO] [stderr]     Checking ssh-muxcontrol v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field `ssh_pid` is never read
[INFO] [stdout]   --> src/commands/check_alive.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 27 | pub struct MuxRespCheckAlive {
[INFO] [stdout]    |            ----------------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 30 |     ssh_pid: u32,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `MuxRespCheckAlive` 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 `ssh_pid` is never read
[INFO] [stdout]   --> src/commands/check_alive.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 27 | pub struct MuxRespCheckAlive {
[INFO] [stdout]    |            ----------------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 30 |     ssh_pid: u32,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `MuxRespCheckAlive` 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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 9.59s
[INFO] running `Command { std: "docker" "inspect" "b612e9c8e74d9981f174eaf8c11470a1f279b898f669409ce1bf4cca3b8dd871", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b612e9c8e74d9981f174eaf8c11470a1f279b898f669409ce1bf4cca3b8dd871", kill_on_drop: false }`
[INFO] [stdout] b612e9c8e74d9981f174eaf8c11470a1f279b898f669409ce1bf4cca3b8dd871
[INFO] checking ssh-muxcontrol-0.1.0 against try#2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2 for never-type-fallback-to-never
[INFO] extracting crate ssh-muxcontrol 0.1.0 into /workspace/builds/worker-4-tc2/source
[INFO] validating manifest of crates.io crate ssh-muxcontrol 0.1.0 on toolchain 2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate ssh-muxcontrol 0.1.0
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate ssh-muxcontrol 0.1.0
[INFO] tweaked toml for crates.io crate ssh-muxcontrol 0.1.0 written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] crate crates.io crate ssh-muxcontrol 0.1.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ffb5809e440193c95555ea3206d619349582ced8724fd2321dd3217a533aecf2
[INFO] running `Command { std: "docker" "start" "-a" "ffb5809e440193c95555ea3206d619349582ced8724fd2321dd3217a533aecf2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ffb5809e440193c95555ea3206d619349582ced8724fd2321dd3217a533aecf2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ffb5809e440193c95555ea3206d619349582ced8724fd2321dd3217a533aecf2", kill_on_drop: false }`
[INFO] [stdout] ffb5809e440193c95555ea3206d619349582ced8724fd2321dd3217a533aecf2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 14281a8286abcc2494cb29528deab1d1a401344e8023106d68a5585b5040e1bc
[INFO] running `Command { std: "docker" "start" "-a" "14281a8286abcc2494cb29528deab1d1a401344e8023106d68a5585b5040e1bc", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.30
[INFO] [stderr]    Compiling syn v1.0.80
[INFO] [stderr]    Compiling libc v0.2.104
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]     Checking pin-project-lite v0.2.7
[INFO] [stderr]     Checking bytes v1.1.0
[INFO] [stderr]    Compiling tokio v1.12.0
[INFO] [stderr]     Checking mio v0.7.14
[INFO] [stderr]    Compiling quote v1.0.10
[INFO] [stderr]    Compiling tokio-macros v1.5.0
[INFO] [stderr]     Checking sendfd v0.4.0
[INFO] [stderr]     Checking tokio-pipe v0.2.1
[INFO] [stderr]     Checking ssh-muxcontrol v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field `ssh_pid` is never read
[INFO] [stdout]   --> src/commands/check_alive.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 27 | pub struct MuxRespCheckAlive {
[INFO] [stdout]    |            ----------------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 30 |     ssh_pid: u32,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `MuxRespCheckAlive` 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 `ssh_pid` is never read
[INFO] [stdout]   --> src/commands/check_alive.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 27 | pub struct MuxRespCheckAlive {
[INFO] [stdout]    |            ----------------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 30 |     ssh_pid: u32,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `MuxRespCheckAlive` 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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 9.30s
[INFO] running `Command { std: "docker" "inspect" "14281a8286abcc2494cb29528deab1d1a401344e8023106d68a5585b5040e1bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "14281a8286abcc2494cb29528deab1d1a401344e8023106d68a5585b5040e1bc", kill_on_drop: false }`
[INFO] [stdout] 14281a8286abcc2494cb29528deab1d1a401344e8023106d68a5585b5040e1bc