[INFO] cloning repository https://github.com/25ma/rust_book
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/25ma/rust_book" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2F25ma%2Frust_book", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2F25ma%2Frust_book'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 394ead8eec2d526c01474e85a7fe7e595b97d712
[INFO] building 25ma/rust_book against master#11663cd3bfefef7d34e8f0892c250bf698049392+rustflags=-Dtail-expr-drop-order for pr-134523
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2F25ma%2Frust_book" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/25ma/rust_book on toolchain 11663cd3bfefef7d34e8f0892c250bf698049392
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/25ma/rust_book
[INFO] finished tweaking git repo https://github.com/25ma/rust_book
[INFO] tweaked toml for git repo https://github.com/25ma/rust_book written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/25ma/rust_book 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" "+11663cd3bfefef7d34e8f0892c250bf698049392" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded getrandom v0.2.4
[INFO] [stderr]   Downloaded libc v0.2.117
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cabc018f135f580014ffab993d9d5ff6d5bca5d4e6bd3e91d78cd2cf289b1259
[INFO] running `Command { std: "docker" "start" "-a" "cabc018f135f580014ffab993d9d5ff6d5bca5d4e6bd3e91d78cd2cf289b1259", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cabc018f135f580014ffab993d9d5ff6d5bca5d4e6bd3e91d78cd2cf289b1259", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cabc018f135f580014ffab993d9d5ff6d5bca5d4e6bd3e91d78cd2cf289b1259", kill_on_drop: false }`
[INFO] [stdout] cabc018f135f580014ffab993d9d5ff6d5bca5d4e6bd3e91d78cd2cf289b1259
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 439b30595ba87feffd201926fa4c4c1168e3f60d26697052cda2b428d725f195
[INFO] running `Command { std: "docker" "start" "-a" "439b30595ba87feffd201926fa4c4c1168e3f60d26697052cda2b428d725f195", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.117
[INFO] [stderr]    Compiling getrandom v0.2.4
[INFO] [stderr]    Compiling rand_core v0.6.3
[INFO] [stderr]    Compiling rand_chacha v0.3.1
[INFO] [stderr]    Compiling rand v0.8.4
[INFO] [stderr]    Compiling rust_book v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: fields `kind` and `address` are never read
[INFO] [stdout]   --> src/06_enums/defining_enum.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 17 |     struct IpAddr {
[INFO] [stdout]    |            ------ fields in this struct
[INFO] [stdout] 18 |         kind: IpAddrKind,
[INFO] [stdout]    |         ^^^^
[INFO] [stdout] 19 |         address: String,
[INFO] [stdout]    |         ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `IpAddr` 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: unused variable: `x`
[INFO] [stdout]   --> src/03_common_programming_concepts/function.rs:10:17
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let mut x = 5 + 1;
[INFO] [stdout]    |                 ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/03_common_programming_concepts/function.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let mut x = 5 + 1;
[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: fields `active`, `username`, `email`, and `sign_in_count` are never read
[INFO] [stdout]   --> src/05_structs/defining_structs.rs:11:9
[INFO] [stdout]    |
[INFO] [stdout] 10 |     struct User {
[INFO] [stdout]    |            ---- fields in this struct
[INFO] [stdout] 11 |         active: bool,
[INFO] [stdout]    |         ^^^^^^
[INFO] [stdout] 12 |         username: String,
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 13 |         email: String,
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout] 14 |         sign_in_count: u64,
[INFO] [stdout]    |         ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `User` 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] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.35s
[INFO] running `Command { std: "docker" "inspect" "439b30595ba87feffd201926fa4c4c1168e3f60d26697052cda2b428d725f195", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "439b30595ba87feffd201926fa4c4c1168e3f60d26697052cda2b428d725f195", kill_on_drop: false }`
[INFO] [stdout] 439b30595ba87feffd201926fa4c4c1168e3f60d26697052cda2b428d725f195
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2388bcf4f332f318719ce065072f7f1f60f9391464ee0243bb5b86bf0c017b0e
[INFO] running `Command { std: "docker" "start" "-a" "2388bcf4f332f318719ce065072f7f1f60f9391464ee0243bb5b86bf0c017b0e", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust_book v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/03_common_programming_concepts/function.rs:10:17
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let mut x = 5 + 1;
[INFO] [stdout]    |                 ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/03_common_programming_concepts/function.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let mut x = 5 + 1;
[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] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.44s
[INFO] running `Command { std: "docker" "inspect" "2388bcf4f332f318719ce065072f7f1f60f9391464ee0243bb5b86bf0c017b0e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2388bcf4f332f318719ce065072f7f1f60f9391464ee0243bb5b86bf0c017b0e", kill_on_drop: false }`
[INFO] [stdout] 2388bcf4f332f318719ce065072f7f1f60f9391464ee0243bb5b86bf0c017b0e