[INFO] fetching crate tac 0.2.3...
[INFO] testing tac-0.2.3 against try#8262275854dc0e5381c9d42d56257d94932c5a87 for pr-90799
[INFO] extracting crate tac 0.2.3 into /workspace/builds/worker-91/source
[INFO] validating manifest of crates.io crate tac 0.2.3 on toolchain 8262275854dc0e5381c9d42d56257d94932c5a87
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8262275854dc0e5381c9d42d56257d94932c5a87" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate tac 0.2.3
[INFO] finished tweaking crates.io crate tac 0.2.3
[INFO] tweaked toml for crates.io crate tac 0.2.3 written to /workspace/builds/worker-91/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8262275854dc0e5381c9d42d56257d94932c5a87" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8262275854dc0e5381c9d42d56257d94932c5a87" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded memmap v0.5.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/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:e8397a04204aaf8b9f284182a6f9e27a3c2e67044d0943b4415b160bfc957681" "/opt/rustwide/cargo-home/bin/cargo" "+8262275854dc0e5381c9d42d56257d94932c5a87" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] fd746ff776160274b05b3df0da97e9190a755a75d92953ab983244370f88459c
[INFO] running `Command { std: "docker" "start" "-a" "fd746ff776160274b05b3df0da97e9190a755a75d92953ab983244370f88459c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "fd746ff776160274b05b3df0da97e9190a755a75d92953ab983244370f88459c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fd746ff776160274b05b3df0da97e9190a755a75d92953ab983244370f88459c", kill_on_drop: false }`
[INFO] [stdout] fd746ff776160274b05b3df0da97e9190a755a75d92953ab983244370f88459c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/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" "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:e8397a04204aaf8b9f284182a6f9e27a3c2e67044d0943b4415b160bfc957681" "/opt/rustwide/cargo-home/bin/cargo" "+8262275854dc0e5381c9d42d56257d94932c5a87" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ffee2ec3b17d2657f2d27068f78155045cfe7fef7b5d3cf78aa7e4173855abad
[INFO] running `Command { std: "docker" "start" "-a" "ffee2ec3b17d2657f2d27068f78155045cfe7fef7b5d3cf78aa7e4173855abad", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.108
[INFO] [stderr]    Compiling rand v0.4.6
[INFO] [stderr]    Compiling memmap v0.5.2
[INFO] [stderr]    Compiling rand v0.3.23
[INFO] [stderr]    Compiling uuid v0.4.0
[INFO] [stderr]    Compiling tac v0.2.3 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the item `Write` is imported redundantly
[INFO] [stdout]   --> src/main.rs:72:9
[INFO] [stdout]    |
[INFO] [stdout] 5  | use std::io::{StdoutLock, Write};
[INFO] [stdout]    |                           ----- the item `Write` is already imported here
[INFO] [stdout] ...
[INFO] [stdout] 72 |     use std::io::Write;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:64:16
[INFO] [stdout]    |
[INFO] [stdout] 64 | fn print_bytes(mut stdout: &mut StdoutLock, bytes: &[u8]) {
[INFO] [stdout]    |                ----^^^^^^
[INFO] [stdout]    |                |
[INFO] [stdout]    |                help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.44s
[INFO] running `Command { std: "docker" "inspect" "ffee2ec3b17d2657f2d27068f78155045cfe7fef7b5d3cf78aa7e4173855abad", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ffee2ec3b17d2657f2d27068f78155045cfe7fef7b5d3cf78aa7e4173855abad", kill_on_drop: false }`
[INFO] [stdout] ffee2ec3b17d2657f2d27068f78155045cfe7fef7b5d3cf78aa7e4173855abad
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/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" "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:e8397a04204aaf8b9f284182a6f9e27a3c2e67044d0943b4415b160bfc957681" "/opt/rustwide/cargo-home/bin/cargo" "+8262275854dc0e5381c9d42d56257d94932c5a87" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 287e9fe055415b85fe940385d3dec22e9736a78936bdc008daf98a764af82610
[INFO] running `Command { std: "docker" "start" "-a" "287e9fe055415b85fe940385d3dec22e9736a78936bdc008daf98a764af82610", kill_on_drop: false }`
[INFO] [stderr]    Compiling tac v0.2.3 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the item `Write` is imported redundantly
[INFO] [stdout]   --> src/main.rs:72:9
[INFO] [stdout]    |
[INFO] [stdout] 5  | use std::io::{StdoutLock, Write};
[INFO] [stdout]    |                           ----- the item `Write` is already imported here
[INFO] [stdout] ...
[INFO] [stdout] 72 |     use std::io::Write;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:64:16
[INFO] [stdout]    |
[INFO] [stdout] 64 | fn print_bytes(mut stdout: &mut StdoutLock, bytes: &[u8]) {
[INFO] [stdout]    |                ----^^^^^^
[INFO] [stdout]    |                |
[INFO] [stdout]    |                help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.49s
[INFO] running `Command { std: "docker" "inspect" "287e9fe055415b85fe940385d3dec22e9736a78936bdc008daf98a764af82610", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "287e9fe055415b85fe940385d3dec22e9736a78936bdc008daf98a764af82610", kill_on_drop: false }`
[INFO] [stdout] 287e9fe055415b85fe940385d3dec22e9736a78936bdc008daf98a764af82610
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-91/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" "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:e8397a04204aaf8b9f284182a6f9e27a3c2e67044d0943b4415b160bfc957681" "/opt/rustwide/cargo-home/bin/cargo" "+8262275854dc0e5381c9d42d56257d94932c5a87" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] ef00d1a9121c819823434ff183114b4d455ff827f79a304164585629c1ccae18
[INFO] running `Command { std: "docker" "start" "-a" "ef00d1a9121c819823434ff183114b4d455ff827f79a304164585629c1ccae18", kill_on_drop: false }`
[INFO] [stderr] warning: the item `Write` is imported redundantly
[INFO] [stderr]   --> src/main.rs:72:9
[INFO] [stderr]    |
[INFO] [stderr] 5  | use std::io::{StdoutLock, Write};
[INFO] [stderr]    |                           ----- the item `Write` is already imported here
[INFO] [stderr] ...
[INFO] [stderr] 72 |     use std::io::Write;
[INFO] [stderr]    |         ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:64:16
[INFO] [stderr]    |
[INFO] [stderr] 64 | fn print_bytes(mut stdout: &mut StdoutLock, bytes: &[u8]) {
[INFO] [stderr]    |                ----^^^^^^
[INFO] [stderr]    |                |
[INFO] [stderr]    |                help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: `tac` (bin "tac" test) generated 2 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.06s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/tac-5c6db331a2aa311a)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "ef00d1a9121c819823434ff183114b4d455ff827f79a304164585629c1ccae18", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ef00d1a9121c819823434ff183114b4d455ff827f79a304164585629c1ccae18", kill_on_drop: false }`
[INFO] [stdout] ef00d1a9121c819823434ff183114b4d455ff827f79a304164585629c1ccae18