[INFO] cloning repository https://github.com/mateja176/rust-demo
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mateja176/rust-demo" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmateja176%2Frust-demo", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmateja176%2Frust-demo'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 64dba55ed48bf94b525352ca5b01647e9fdab079
[INFO] checking mateja176/rust-demo against master#f8f6997469237299c1d60814c7b9828602a1f8e4 for pr-143808
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmateja176%2Frust-demo" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/mateja176/rust-demo
[INFO] finished tweaking git repo https://github.com/mateja176/rust-demo
[INFO] tweaked toml for git repo https://github.com/mateja176/rust-demo written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/mateja176/rust-demo on toolchain f8f6997469237299c1d60814c7b9828602a1f8e4
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+f8f6997469237299c1d60814c7b9828602a1f8e4" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/mateja176/rust-demo 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" "+f8f6997469237299c1d60814c7b9828602a1f8e4" "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] 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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+f8f6997469237299c1d60814c7b9828602a1f8e4" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] bfb8defb60aedfbf0f1efe9aa72c202437499ec000a029876e33eb897cba1199
[INFO] running `Command { std: "docker" "start" "-a" "bfb8defb60aedfbf0f1efe9aa72c202437499ec000a029876e33eb897cba1199", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "bfb8defb60aedfbf0f1efe9aa72c202437499ec000a029876e33eb897cba1199", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bfb8defb60aedfbf0f1efe9aa72c202437499ec000a029876e33eb897cba1199", kill_on_drop: false }`
[INFO] [stdout] bfb8defb60aedfbf0f1efe9aa72c202437499ec000a029876e33eb897cba1199
[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" "-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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+f8f6997469237299c1d60814c7b9828602a1f8e4" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6922225d2c7b55577438ae6c382f712bbea632af6636a50c025f125d96a57f2f
[INFO] running `Command { std: "docker" "start" "-a" "6922225d2c7b55577438ae6c382f712bbea632af6636a50c025f125d96a57f2f", kill_on_drop: false }`
[INFO] [stderr]     Checking rust-demo v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/main.rs:34:9
[INFO] [stdout]    |
[INFO] [stdout] 34 |     let b = RcList::Cons(2, Rc::clone(&a));
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/main.rs:37:13
[INFO] [stdout]    |
[INFO] [stdout] 37 |         let c = RcList::Cons(3, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/main.rs:11:14
[INFO] [stdout]    |
[INFO] [stdout] 11 |         Cons(i32, Box<List>),
[INFO] [stdout]    |         ---- ^^^  ^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `List` 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] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 11 -         Cons(i32, Box<List>),
[INFO] [stdout] 11 +         Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/main.rs:20:14
[INFO] [stdout]    |
[INFO] [stdout] 20 |         Cons(i32, Rc<RcList>),
[INFO] [stdout]    |         ---- ^^^  ^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `RcList` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 20 -         Cons(i32, Rc<RcList>),
[INFO] [stdout] 20 +         Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/main.rs:34:9
[INFO] [stdout]    |
[INFO] [stdout] 34 |     let b = RcList::Cons(2, Rc::clone(&a));
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/main.rs:37:13
[INFO] [stdout]    |
[INFO] [stdout] 37 |         let c = RcList::Cons(3, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.20s
[INFO] running `Command { std: "docker" "inspect" "6922225d2c7b55577438ae6c382f712bbea632af6636a50c025f125d96a57f2f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6922225d2c7b55577438ae6c382f712bbea632af6636a50c025f125d96a57f2f", kill_on_drop: false }`
[INFO] [stdout] 6922225d2c7b55577438ae6c382f712bbea632af6636a50c025f125d96a57f2f