[INFO] cloning repository https://github.com/GHvW/frothy-rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/GHvW/frothy-rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FGHvW%2Ffrothy-rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FGHvW%2Ffrothy-rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f122bce431b431b33644d4fbc77b4e575cfd4016
[INFO] testing GHvW/frothy-rs against beta-2020-07-24 for beta-1.46-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FGHvW%2Ffrothy-rs" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/GHvW/frothy-rs on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/GHvW/frothy-rs
[INFO] finished tweaking git repo https://github.com/GHvW/frothy-rs
[INFO] tweaked toml for git repo https://github.com/GHvW/frothy-rs written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/GHvW/frothy-rs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "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] 13e5c4fc63c3d3f24d945284b78e9e3a24d1df4caaca9ce3554759a56b734230
[INFO] running `Command { std: "docker" "start" "-a" "13e5c4fc63c3d3f24d945284b78e9e3a24d1df4caaca9ce3554759a56b734230", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "13e5c4fc63c3d3f24d945284b78e9e3a24d1df4caaca9ce3554759a56b734230", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "13e5c4fc63c3d3f24d945284b78e9e3a24d1df4caaca9ce3554759a56b734230", kill_on_drop: false }`
[INFO] [stdout] 13e5c4fc63c3d3f24d945284b78e9e3a24d1df4caaca9ce3554759a56b734230
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "build" "--frozen" "--message-format=json", 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] 08fe56bfcc6a447f7137248c9c065c35edbb116b60d5a2f84c947582b578f2b2
[INFO] running `Command { std: "docker" "start" "-a" "08fe56bfcc6a447f7137248c9c065c35edbb116b60d5a2f84c947582b578f2b2", kill_on_drop: false }`
[INFO] [stderr]    Compiling frothy_rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `Read`
[INFO] [stdout]  --> src/main.rs:3:22
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::io::{Write, Read};
[INFO] [stdout]   |                      ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: `impl Stack<String>` doesn't implement `std::fmt::Debug`
[INFO] [stdout]   --> src/main.rs:72:37
[INFO] [stdout]    |
[INFO] [stdout] 72 |     println!("current stack: {:?}", *stack);
[INFO] [stdout]    |                                     ^^^^^^ `impl Stack<String>` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `std::fmt::Debug` is not implemented for `impl Stack<String>`
[INFO] [stdout]    = note: required by `std::fmt::Debug::fmt`
[INFO] [stdout]    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] help: consider further restricting this bound
[INFO] [stdout]    |
[INFO] [stdout] 71 | fn repl(stack: &mut impl Stack<String> + std::fmt::Debug) -> () {
[INFO] [stdout]    |                                        ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `frothy_rs`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "08fe56bfcc6a447f7137248c9c065c35edbb116b60d5a2f84c947582b578f2b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "08fe56bfcc6a447f7137248c9c065c35edbb116b60d5a2f84c947582b578f2b2", kill_on_drop: false }`
[INFO] [stdout] 08fe56bfcc6a447f7137248c9c065c35edbb116b60d5a2f84c947582b578f2b2