[INFO] fetching crate tac 0.2.3...
[INFO] testing tac-0.2.3 against try#722e1797249a965b6335aebd65d777f917e498f1 for pr-91031
[INFO] extracting crate tac 0.2.3 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate tac 0.2.3 on toolchain 722e1797249a965b6335aebd65d777f917e498f1
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "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-5/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 475107a6042f0d82c8b080c9fd00b67dcf0c6956c5147f0d3c6a140d7b28ca38
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "475107a6042f0d82c8b080c9fd00b67dcf0c6956c5147f0d3c6a140d7b28ca38", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "475107a6042f0d82c8b080c9fd00b67dcf0c6956c5147f0d3c6a140d7b28ca38", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "475107a6042f0d82c8b080c9fd00b67dcf0c6956c5147f0d3c6a140d7b28ca38", kill_on_drop: false }`
[INFO] [stdout] 475107a6042f0d82c8b080c9fd00b67dcf0c6956c5147f0d3c6a140d7b28ca38
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] a1048f9581488bd93c8dc530781752991283efdb56d72fde7f9e7a317873fee2
[INFO] running `Command { std: "docker" "start" "-a" "a1048f9581488bd93c8dc530781752991283efdb56d72fde7f9e7a317873fee2", kill_on_drop: false }`
[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 3.98s
[INFO] running `Command { std: "docker" "inspect" "a1048f9581488bd93c8dc530781752991283efdb56d72fde7f9e7a317873fee2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a1048f9581488bd93c8dc530781752991283efdb56d72fde7f9e7a317873fee2", kill_on_drop: false }`
[INFO] [stdout] a1048f9581488bd93c8dc530781752991283efdb56d72fde7f9e7a317873fee2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 5b179d2b77fb2a75b242b5fba8c573928c707790cc7f93985f17a5d274170b9b
[INFO] running `Command { std: "docker" "start" "-a" "5b179d2b77fb2a75b242b5fba8c573928c707790cc7f93985f17a5d274170b9b", 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 0.77s
[INFO] running `Command { std: "docker" "inspect" "5b179d2b77fb2a75b242b5fba8c573928c707790cc7f93985f17a5d274170b9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b179d2b77fb2a75b242b5fba8c573928c707790cc7f93985f17a5d274170b9b", kill_on_drop: false }`
[INFO] [stdout] 5b179d2b77fb2a75b242b5fba8c573928c707790cc7f93985f17a5d274170b9b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 66736c5ebbcffe9633565b10a43e437f7a806942676063c3fe7f166d8c5bd952
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "66736c5ebbcffe9633565b10a43e437f7a806942676063c3fe7f166d8c5bd952", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: the item `Write` is imported redundantly
[INFO] [stdout] running 0 tests
[INFO] [stderr]   --> src/main.rs:72:9
[INFO] [stdout] 
[INFO] [stderr]    |
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] 5  | use std::io::{StdoutLock, Write};
[INFO] [stdout] 
[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 0.03s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/tac-51eb4fa9c357d502)
[INFO] running `Command { std: "docker" "inspect" "66736c5ebbcffe9633565b10a43e437f7a806942676063c3fe7f166d8c5bd952", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "66736c5ebbcffe9633565b10a43e437f7a806942676063c3fe7f166d8c5bd952", kill_on_drop: false }`
[INFO] [stdout] 66736c5ebbcffe9633565b10a43e437f7a806942676063c3fe7f166d8c5bd952