[INFO] cloning repository https://github.com/morlinbrot/linked_list
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/morlinbrot/linked_list" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmorlinbrot%2Flinked_list", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmorlinbrot%2Flinked_list'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 6d450ed915a2d239b0a799f3a8a6f52f6f2586ec
[INFO] checking morlinbrot/linked_list against try#de39175d9e0f63ff8967b81f9639ba28d11ae6ef for pr-135331
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmorlinbrot%2Flinked_list" "/workspace/builds/worker-3-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/morlinbrot/linked_list on toolchain de39175d9e0f63ff8967b81f9639ba28d11ae6ef
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+de39175d9e0f63ff8967b81f9639ba28d11ae6ef" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/morlinbrot/linked_list
[INFO] finished tweaking git repo https://github.com/morlinbrot/linked_list
[INFO] tweaked toml for git repo https://github.com/morlinbrot/linked_list written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/morlinbrot/linked_list 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" "+de39175d9e0f63ff8967b81f9639ba28d11ae6ef" "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-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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" "+de39175d9e0f63ff8967b81f9639ba28d11ae6ef" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0d3ecbe8134e0a44b81e9b433208a73440ac3717879a0d1d5f9825ed8b0b40a0
[INFO] running `Command { std: "docker" "start" "-a" "0d3ecbe8134e0a44b81e9b433208a73440ac3717879a0d1d5f9825ed8b0b40a0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0d3ecbe8134e0a44b81e9b433208a73440ac3717879a0d1d5f9825ed8b0b40a0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0d3ecbe8134e0a44b81e9b433208a73440ac3717879a0d1d5f9825ed8b0b40a0", kill_on_drop: false }`
[INFO] [stdout] 0d3ecbe8134e0a44b81e9b433208a73440ac3717879a0d1d5f9825ed8b0b40a0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+de39175d9e0f63ff8967b81f9639ba28d11ae6ef" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 55b020bab7b31ef2c32bea60a5b3f27872e88f1bab034d8559ee5c040a89669a
[INFO] running `Command { std: "docker" "start" "-a" "55b020bab7b31ef2c32bea60a5b3f27872e88f1bab034d8559ee5c040a89669a", kill_on_drop: false }`
[INFO] [stderr]     Checking linked-lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `Option::<T>::map_or` that must be used
[INFO] [stdout]    --> src/_07_prod_unsafe_deque/cursor.rs:224:9
[INFO] [stdout]     |
[INFO] [stdout] 224 |         self.idx.map_or(other_len - 1, |v| v + other_len);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the returned value, use `if let` instead
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 224 |         let _ = self.idx.map_or(other_len - 1, |v| v + other_len);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Option::<T>::map_or` that must be used
[INFO] [stdout]    --> src/_07_prod_unsafe_deque/cursor.rs:224:9
[INFO] [stdout]     |
[INFO] [stdout] 224 |         self.idx.map_or(other_len - 1, |v| v + other_len);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the returned value, use `if let` instead
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 224 |         let _ = self.idx.map_or(other_len - 1, |v| v + other_len);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.31s
[INFO] running `Command { std: "docker" "inspect" "55b020bab7b31ef2c32bea60a5b3f27872e88f1bab034d8559ee5c040a89669a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "55b020bab7b31ef2c32bea60a5b3f27872e88f1bab034d8559ee5c040a89669a", kill_on_drop: false }`
[INFO] [stdout] 55b020bab7b31ef2c32bea60a5b3f27872e88f1bab034d8559ee5c040a89669a