[INFO] updating cached repository riku179/monkey-lang-rust
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/riku179/monkey-lang-rust
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/riku179/monkey-lang-rust" "work/ex/beta-1.38-1/sources/1.37.0/gh/riku179/monkey-lang-rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/riku179/monkey-lang-rust'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/riku179/monkey-lang-rust" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/riku179/monkey-lang-rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/riku179/monkey-lang-rust'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 4e87a096504b96df0b6ffd15c8567f777960e32c
[INFO] sha for GitHub repo riku179/monkey-lang-rust: 4e87a096504b96df0b6ffd15c8567f777960e32c
[INFO] validating manifest of riku179/monkey-lang-rust on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of riku179/monkey-lang-rust on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing riku179/monkey-lang-rust
[INFO] finished frobbing riku179/monkey-lang-rust
[INFO] frobbed toml for riku179/monkey-lang-rust written to work/ex/beta-1.38-1/sources/1.37.0/gh/riku179/monkey-lang-rust/Cargo.toml
[INFO] started frobbing riku179/monkey-lang-rust
[INFO] finished frobbing riku179/monkey-lang-rust
[INFO] frobbed toml for riku179/monkey-lang-rust written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/riku179/monkey-lang-rust/Cargo.toml
[INFO] crate riku179/monkey-lang-rust already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing riku179/monkey-lang-rust against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/riku179/monkey-lang-rust:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 4664c7438a9d69cd5d872d685885b5d353472106705a9e503a144cd348e07ba5
[INFO] running `"docker" "start" "-a" "4664c7438a9d69cd5d872d685885b5d353472106705a9e503a144cd348e07ba5"`
[INFO] [stderr]    Compiling ascii v0.9.1
[INFO] [stderr]    Compiling monkey_lang v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/main.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(never_type)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/main.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(box_patterns)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `ascii::AsciiString`
[INFO] [stderr]  --> src/repl/mod.rs:1:5
[INFO] [stderr]   |
[INFO] [stderr] 1 | use ascii::AsciiString;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::str::FromStr`
[INFO] [stderr]  --> src/repl/mod.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::str::FromStr;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `crate::token::Token`
[INFO] [stderr]  --> src/repl/mod.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 | use crate::token::Token;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused imports: `Debug`, `Display`
[INFO] [stderr]  --> src/evaluator/mod.rs:1:16
[INFO] [stderr]   |
[INFO] [stderr] 1 | use std::fmt::{Debug, Display};
[INFO] [stderr]   |                ^^^^^  ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Ident`
[INFO] [stderr]  --> src/evaluator/mod.rs:2:27
[INFO] [stderr]   |
[INFO] [stderr] 2 | use crate::ast::{Program, Ident, Stmt, Expr, Literal, Prefix, Infix};
[INFO] [stderr]   |                           ^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `monkey_lang`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "4664c7438a9d69cd5d872d685885b5d353472106705a9e503a144cd348e07ba5"`
[INFO] running `"docker" "rm" "-f" "4664c7438a9d69cd5d872d685885b5d353472106705a9e503a144cd348e07ba5"`
[INFO] [stdout] 4664c7438a9d69cd5d872d685885b5d353472106705a9e503a144cd348e07ba5