[INFO] updating cached repository https://github.com/calebwin/fern
[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] 9e5da73a0152faa92f4cf96b504e42d82d9448f4
[INFO] testing calebwin/fern against beta-2020-06-03 for beta-1.45-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcalebwin%2Ffern" "/workspace/builds/worker-10/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/calebwin/fern 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/calebwin/fern
[INFO] finished tweaking git repo https://github.com/calebwin/fern
[INFO] tweaked toml for git repo https://github.com/calebwin/fern written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/calebwin/fern 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] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 3c30f96167afb4ba849f6f105bce49c2da4dcc454009f13e00932e5351022921
[INFO] running `"docker" "start" "-a" "3c30f96167afb4ba849f6f105bce49c2da4dcc454009f13e00932e5351022921"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling libc v0.2.48
[INFO] [stderr]    Compiling backtrace-sys v0.1.28
[INFO] [stderr]    Compiling backtrace v0.3.13
[INFO] [stderr]    Compiling error-chain v0.12.0
[INFO] [stderr]    Compiling rsmt2 v0.10.0
[INFO] [stderr]    Compiling fern v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused import: `SmtRes`
[INFO] [stderr]  --> src/main.rs:4:13
[INFO] [stderr]   |
[INFO] [stderr] 4 | use rsmt2::{SmtRes, Solver};
[INFO] [stderr]   |             ^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] error[E0277]: `rsmt2::example::simple::Cst` doesn't implement `std::fmt::Debug`
[INFO] [stderr]   --> src/main.rs:32:26
[INFO] [stderr]    |
[INFO] [stderr] 32 |         println!("{:?}", model);
[INFO] [stderr]    |                          ^^^^^ `rsmt2::example::simple::Cst` 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 `rsmt2::example::simple::Cst`
[INFO] [stderr]    = note: required because of the requirements on the impl of `std::fmt::Debug` for `(std::string::String, std::string::String, rsmt2::example::simple::Cst)`
[INFO] [stderr]    = note: required because of the requirements on the impl of `std::fmt::Debug` for `std::vec::Vec<(std::string::String, std::string::String, rsmt2::example::simple::Cst)>`
[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] 
[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 `fern`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "3c30f96167afb4ba849f6f105bce49c2da4dcc454009f13e00932e5351022921"`
[INFO] running `"docker" "rm" "-f" "3c30f96167afb4ba849f6f105bce49c2da4dcc454009f13e00932e5351022921"`
[INFO] [stdout] 3c30f96167afb4ba849f6f105bce49c2da4dcc454009f13e00932e5351022921