[INFO] cloning repository https://github.com/Cupnfish/my-leetcode-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Cupnfish/my-leetcode-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCupnfish%2Fmy-leetcode-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCupnfish%2Fmy-leetcode-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 32002f7714d5be3b547d0280955407e3f02fc1f1
[INFO] testing Cupnfish/my-leetcode-rust against master#432e145bd5a974c5b6f4dd9b352891bd7502b69d for pr-87041
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCupnfish%2Fmy-leetcode-rust" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Cupnfish/my-leetcode-rust on toolchain 432e145bd5a974c5b6f4dd9b352891bd7502b69d
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Cupnfish/my-leetcode-rust
[INFO] finished tweaking git repo https://github.com/Cupnfish/my-leetcode-rust
[INFO] tweaked toml for git repo https://github.com/Cupnfish/my-leetcode-rust written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/Cupnfish/my-leetcode-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 8fde9515cbeca149b8e1e84a09bd2f27696843902d243d80c7602ce89697286d
[INFO] running `Command { std: "docker" "start" "-a" "8fde9515cbeca149b8e1e84a09bd2f27696843902d243d80c7602ce89697286d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8fde9515cbeca149b8e1e84a09bd2f27696843902d243d80c7602ce89697286d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8fde9515cbeca149b8e1e84a09bd2f27696843902d243d80c7602ce89697286d", kill_on_drop: false }`
[INFO] [stdout] 8fde9515cbeca149b8e1e84a09bd2f27696843902d243d80c7602ce89697286d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5281f5d7e73d868e42482a2cd0ac184cce1bfe2b7e18760490359b8c0e4bbb2b
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "5281f5d7e73d868e42482a2cd0ac184cce1bfe2b7e18760490359b8c0e4bbb2b", kill_on_drop: false }`
[INFO] [stderr]    Compiling leetcode-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::iter::Zip`
[INFO] [stdout]  --> src/random/day2.rs:2:9
[INFO] [stdout]   |
[INFO] [stdout] 2 |     use std::iter::Zip;
[INFO] [stdout]   |         ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `hash`
[INFO] [stdout]  --> src/random/day3.rs:2:52
[INFO] [stdout]   |
[INFO] [stdout] 2 |     use std::{cell::RefCell, collections::HashMap, hash, rc::Rc};
[INFO] [stdout]   |                                                    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: use of unstable library feature 'map_first_last'
[INFO] [stdout]    --> src/random/day3.rs:103:41
[INFO] [stdout]     |
[INFO] [stdout] 103 |         if let Some(mut entry) = counts.first_entry() {
[INFO] [stdout]     |                                         ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: see issue #62924 <https://github.com/rust-lang/rust/issues/62924> for more information
[INFO] [stdout]     = help: add `#![feature(map_first_last)]` to the crate attributes to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0658`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `leetcode-rust`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "5281f5d7e73d868e42482a2cd0ac184cce1bfe2b7e18760490359b8c0e4bbb2b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5281f5d7e73d868e42482a2cd0ac184cce1bfe2b7e18760490359b8c0e4bbb2b", kill_on_drop: false }`
[INFO] [stdout] 5281f5d7e73d868e42482a2cd0ac184cce1bfe2b7e18760490359b8c0e4bbb2b