[INFO] updating cached repository https://github.com/GHvW/frothy-rs
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] f122bce431b431b33644d4fbc77b4e575cfd4016
[INFO] testing GHvW/frothy-rs against beta-2020-06-03 for beta-1.45-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FGHvW%2Ffrothy-rs" "/workspace/builds/worker-12/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/GHvW/frothy-rs on toolchain beta-2020-06-03
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "read-manifest" "--manifest-path" "Cargo.toml"`
[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-12/source/Cargo.toml
[INFO] crate git repo https://github.com/GHvW/frothy-rs already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-06-03" "build" "--frozen"`
[INFO] [stdout] 6271eecbdae206700c16c294ba32368192207d58fa9b0f529a9cbf7e9a60a8e4
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "6271eecbdae206700c16c294ba32368192207d58fa9b0f529a9cbf7e9a60a8e4"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling frothy_rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused import: `Read`
[INFO] [stderr]  --> src/main.rs:3:22
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::io::{Write, Read};
[INFO] [stderr]   |                      ^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] error[E0277]: `impl Stack<String>` doesn't implement `std::fmt::Debug`
[INFO] [stderr]   --> src/main.rs:72:37
[INFO] [stderr]    |
[INFO] [stderr] 72 |     println!("current stack: {:?}", *stack);
[INFO] [stderr]    |                                     ^^^^^^ `impl Stack<String>` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
[INFO] [stderr]    |
[INFO] [stderr]    = help: the trait `std::fmt::Debug` is not implemented for `impl Stack<String>`
[INFO] [stderr]    = note: required by `std::fmt::Debug::fmt`
[INFO] [stderr]    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] help: consider further restricting this bound
[INFO] [stderr]    |
[INFO] [stderr] 71 | fn repl(stack: &mut impl Stack<String> + std::fmt::Debug) -> () {
[INFO] [stderr]    |                                        ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error; 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0277`.
[INFO] [stderr] error: could not compile `frothy_rs`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "6271eecbdae206700c16c294ba32368192207d58fa9b0f529a9cbf7e9a60a8e4"`
[INFO] running `"docker" "rm" "-f" "6271eecbdae206700c16c294ba32368192207d58fa9b0f529a9cbf7e9a60a8e4"`
[INFO] [stdout] 6271eecbdae206700c16c294ba32368192207d58fa9b0f529a9cbf7e9a60a8e4