[INFO] fetching crate tac 0.2.3...
[INFO] testing tac-0.2.3 against master#b70888601af92f6cdc0364abab3446e418b91d36 for pr-86479
[INFO] extracting crate tac 0.2.3 into /workspace/builds/worker-15/source
[INFO] validating manifest of crates.io crate tac 0.2.3 on toolchain b70888601af92f6cdc0364abab3446e418b91d36
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "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-15/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4443d55a7c21e76491cfc658b58c0e76c59ffae6230ada1393b9b83e67494210
[INFO] running `Command { std: "docker" "start" "-a" "4443d55a7c21e76491cfc658b58c0e76c59ffae6230ada1393b9b83e67494210", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4443d55a7c21e76491cfc658b58c0e76c59ffae6230ada1393b9b83e67494210", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4443d55a7c21e76491cfc658b58c0e76c59ffae6230ada1393b9b83e67494210", kill_on_drop: false }`
[INFO] [stdout] 4443d55a7c21e76491cfc658b58c0e76c59ffae6230ada1393b9b83e67494210
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1d2473f30e222d2a3c7da04315de12363bd23c7b3041d23e26f2bc8cee4e4729
[INFO] running `Command { std: "docker" "start" "-a" "1d2473f30e222d2a3c7da04315de12363bd23c7b3041d23e26f2bc8cee4e4729", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.98
[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 3.34s
[INFO] running `Command { std: "docker" "inspect" "1d2473f30e222d2a3c7da04315de12363bd23c7b3041d23e26f2bc8cee4e4729", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1d2473f30e222d2a3c7da04315de12363bd23c7b3041d23e26f2bc8cee4e4729", kill_on_drop: false }`
[INFO] [stdout] 1d2473f30e222d2a3c7da04315de12363bd23c7b3041d23e26f2bc8cee4e4729
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] fc785c4e8e838e8c19705619bbc80fc4c48d93a7769370240131c35b630d279f
[INFO] running `Command { std: "docker" "start" "-a" "fc785c4e8e838e8c19705619bbc80fc4c48d93a7769370240131c35b630d279f", 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 0.27s
[INFO] running `Command { std: "docker" "inspect" "fc785c4e8e838e8c19705619bbc80fc4c48d93a7769370240131c35b630d279f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fc785c4e8e838e8c19705619bbc80fc4c48d93a7769370240131c35b630d279f", kill_on_drop: false }`
[INFO] [stdout] fc785c4e8e838e8c19705619bbc80fc4c48d93a7769370240131c35b630d279f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 5ecc7b1dd696eac7fbede49afbfeda2ca2e6bd843a73b41e6578020eb6bff7f8
[INFO] running `Command { std: "docker" "start" "-a" "5ecc7b1dd696eac7fbede49afbfeda2ca2e6bd843a73b41e6578020eb6bff7f8", 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 0.01s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/tac-0aa87837692c1129)
[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" "5ecc7b1dd696eac7fbede49afbfeda2ca2e6bd843a73b41e6578020eb6bff7f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5ecc7b1dd696eac7fbede49afbfeda2ca2e6bd843a73b41e6578020eb6bff7f8", kill_on_drop: false }`
[INFO] [stdout] 5ecc7b1dd696eac7fbede49afbfeda2ca2e6bd843a73b41e6578020eb6bff7f8