[INFO] cloning repository https://github.com/fahrenkrug/rust_learn_book_errors
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/fahrenkrug/rust_learn_book_errors" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffahrenkrug%2Frust_learn_book_errors", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffahrenkrug%2Frust_learn_book_errors'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] aa959a404d3e1af5bf3df0465fa974898c211764
[INFO] testing fahrenkrug/rust_learn_book_errors against master#b70888601af92f6cdc0364abab3446e418b91d36 for pr-86479
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffahrenkrug%2Frust_learn_book_errors" "/workspace/builds/worker-10/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fahrenkrug/rust_learn_book_errors 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 git repo https://github.com/fahrenkrug/rust_learn_book_errors
[INFO] finished tweaking git repo https://github.com/fahrenkrug/rust_learn_book_errors
[INFO] tweaked toml for git repo https://github.com/fahrenkrug/rust_learn_book_errors written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/fahrenkrug/rust_learn_book_errors already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b70888601af92f6cdc0364abab3446e418b91d36" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] 8196bfef024bef988b8007eb9ff305f0a12a39127851b89a0ff40c694fbf34af
[INFO] running `Command { std: "docker" "start" "-a" "8196bfef024bef988b8007eb9ff305f0a12a39127851b89a0ff40c694fbf34af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8196bfef024bef988b8007eb9ff305f0a12a39127851b89a0ff40c694fbf34af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8196bfef024bef988b8007eb9ff305f0a12a39127851b89a0ff40c694fbf34af", kill_on_drop: false }`
[INFO] [stdout] 8196bfef024bef988b8007eb9ff305f0a12a39127851b89a0ff40c694fbf34af
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] 24d79f5c72fedae383ff3d94d7baa596826630b3ea682e89c1afd45e59e01c62
[INFO] running `Command { std: "docker" "start" "-a" "24d79f5c72fedae383ff3d94d7baa596826630b3ea682e89c1afd45e59e01c62", kill_on_drop: false }`
[INFO] [stderr]    Compiling errors v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/main.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let f = File::open("hello.txt")?;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> src/main.rs:69:4
[INFO] [stdout]    |
[INFO] [stdout] 69 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` 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 0.59s
[INFO] running `Command { std: "docker" "inspect" "24d79f5c72fedae383ff3d94d7baa596826630b3ea682e89c1afd45e59e01c62", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "24d79f5c72fedae383ff3d94d7baa596826630b3ea682e89c1afd45e59e01c62", kill_on_drop: false }`
[INFO] [stdout] 24d79f5c72fedae383ff3d94d7baa596826630b3ea682e89c1afd45e59e01c62
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] 78a47e818e40a7e3e39db22dc2c635722b7d0ad60d1b7ddadf1ed2b9e6deffed
[INFO] running `Command { std: "docker" "start" "-a" "78a47e818e40a7e3e39db22dc2c635722b7d0ad60d1b7ddadf1ed2b9e6deffed", kill_on_drop: false }`
[INFO] [stderr]    Compiling errors v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/main.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let f = File::open("hello.txt")?;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> src/main.rs:69:4
[INFO] [stdout]    |
[INFO] [stdout] 69 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.57s
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "78a47e818e40a7e3e39db22dc2c635722b7d0ad60d1b7ddadf1ed2b9e6deffed", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "78a47e818e40a7e3e39db22dc2c635722b7d0ad60d1b7ddadf1ed2b9e6deffed", kill_on_drop: false }`
[INFO] [stdout] 78a47e818e40a7e3e39db22dc2c635722b7d0ad60d1b7ddadf1ed2b9e6deffed
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] 3a562574bde4b87b790f9cebce31ce66d376a41dbe91d181b2f2783315b7bd90
[INFO] running `Command { std: "docker" "start" "-a" "3a562574bde4b87b790f9cebce31ce66d376a41dbe91d181b2f2783315b7bd90", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: unused variable: `f`
[INFO] [stdout] running 0 tests
[INFO] [stderr]   --> src/main.rs:65:9
[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] 65 |     let f = File::open("hello.txt")?;
[INFO] [stdout] 
[INFO] [stderr]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `read_username_from_file`
[INFO] [stderr]   --> src/main.rs:69:4
[INFO] [stderr]    |
[INFO] [stderr] 69 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stderr]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: `errors` (bin "errors" test) generated 2 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/errors-529b2646a83a38d8)
[INFO] running `Command { std: "docker" "inspect" "3a562574bde4b87b790f9cebce31ce66d376a41dbe91d181b2f2783315b7bd90", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3a562574bde4b87b790f9cebce31ce66d376a41dbe91d181b2f2783315b7bd90", kill_on_drop: false }`
[INFO] [stdout] 3a562574bde4b87b790f9cebce31ce66d376a41dbe91d181b2f2783315b7bd90