[INFO] updating cached repository ghotiphud/rust-intro [INFO] running `"git" "fetch" "--all"` [INFO] [stdout] Fetching origin [INFO] [stderr] From git://github.com/ghotiphud/rust-intro [INFO] [stderr] * branch HEAD -> FETCH_HEAD [INFO] running `"git" "clone" "work/cache/sources/gh/ghotiphud/rust-intro" "work/ex/beta-1.38-1/sources/1.37.0/gh/ghotiphud/rust-intro"` [INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/ghotiphud/rust-intro'... [INFO] [stderr] done. [INFO] running `"git" "clone" "work/cache/sources/gh/ghotiphud/rust-intro" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/ghotiphud/rust-intro"` [INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/ghotiphud/rust-intro'... [INFO] [stderr] done. [INFO] running `"git" "rev-parse" "HEAD"` [INFO] [stdout] c72640c3eb4a803d29bd3eb29798bcb85e9b4054 [INFO] sha for GitHub repo ghotiphud/rust-intro: c72640c3eb4a803d29bd3eb29798bcb85e9b4054 [INFO] validating manifest of ghotiphud/rust-intro 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 ghotiphud/rust-intro 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 ghotiphud/rust-intro [INFO] finished frobbing ghotiphud/rust-intro [INFO] frobbed toml for ghotiphud/rust-intro written to work/ex/beta-1.38-1/sources/1.37.0/gh/ghotiphud/rust-intro/Cargo.toml [INFO] started frobbing ghotiphud/rust-intro [INFO] finished frobbing ghotiphud/rust-intro [INFO] frobbed toml for ghotiphud/rust-intro written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/ghotiphud/rust-intro/Cargo.toml [INFO] crate ghotiphud/rust-intro 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] [stderr] Blocking waiting for file lock on package cache [INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"` [INFO] testing ghotiphud/rust-intro 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-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/ghotiphud/rust-intro:/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] 4abe8bb57e6d142de3695eb12d4d48769198b825951218e74ab49bcfa15d980e [INFO] running `"docker" "start" "-a" "4abe8bb57e6d142de3695eb12d4d48769198b825951218e74ab49bcfa15d980e"` [INFO] [stderr] Compiling rust_intro v0.1.0 (/opt/crater/workdir) [INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel [INFO] [stderr] --> src/types.rs:1:1 [INFO] [stderr] | [INFO] [stderr] 1 | #![feature(core_intrinsics)] [INFO] [stderr] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [INFO] [stderr] [INFO] [stderr] warning: unused return value of `std::iter::Iterator::collect` that must be used [INFO] [stderr] --> src/concurrent.rs:140:5 [INFO] [stderr] | [INFO] [stderr] 140 | handles.into_iter().map(|h| h.join().unwrap()).collect::>(); [INFO] [stderr] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [INFO] [stderr] | [INFO] [stderr] = note: #[warn(unused_must_use)] on by default [INFO] [stderr] = note: if you really need to exhaust the iterator, consider `.for_each(drop)` instead [INFO] [stderr] [INFO] [stderr] error: aborting due to previous error [INFO] [stderr] [INFO] [stderr] For more information about this error, try `rustc --explain E0554`. [INFO] [stderr] error: Could not compile `rust_intro`. [INFO] [stderr] warning: build failed, waiting for other jobs to finish... [INFO] [stderr] warning: unused variable: `y` [INFO] [stderr] --> src/main.rs:5:9 [INFO] [stderr] | [INFO] [stderr] 5 | let y = &x[0]; //Borrow(Reference) the first element of x [INFO] [stderr] | ^ help: consider prefixing with an underscore: `_y` [INFO] [stderr] | [INFO] [stderr] = note: #[warn(unused_variables)] on by default [INFO] [stderr] [INFO] [stderr] warning: unused variable: `y` [INFO] [stderr] --> src/safety.rs:3:9 [INFO] [stderr] | [INFO] [stderr] 3 | let y = &x[0]; //Borrow(Reference) the first element of x [INFO] [stderr] | ^ help: consider prefixing with an underscore: `_y` [INFO] [stderr] | [INFO] [stderr] = note: #[warn(unused_variables)] on by default [INFO] [stderr] [INFO] [stderr] warning: variable does not need to be mutable [INFO] [stderr] --> src/safety.rs:2:9 [INFO] [stderr] | [INFO] [stderr] 2 | let mut x = vec![10, 20]; //Create vec owned by x [INFO] [stderr] | ----^ [INFO] [stderr] | | [INFO] [stderr] | help: remove this `mut` [INFO] [stderr] | [INFO] [stderr] = note: #[warn(unused_mut)] on by default [INFO] [stderr] [INFO] [stderr] warning: function is never used: `iterator` [INFO] [stderr] --> src/main.rs:9:1 [INFO] [stderr] | [INFO] [stderr] 9 | fn iterator() { [INFO] [stderr] | ^^^^^^^^^^^^^ [INFO] [stderr] | [INFO] [stderr] = note: #[warn(dead_code)] on by default [INFO] [stderr] [INFO] [stderr] warning: function is never used: `sum_pos` [INFO] [stderr] --> src/main.rs:16:1 [INFO] [stderr] | [INFO] [stderr] 16 | fn sum_pos(v: &Vec) -> i32 { [INFO] [stderr] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [INFO] [stderr] [INFO] [stderr] error: build failed [INFO] running `"docker" "inspect" "4abe8bb57e6d142de3695eb12d4d48769198b825951218e74ab49bcfa15d980e"` [INFO] running `"docker" "rm" "-f" "4abe8bb57e6d142de3695eb12d4d48769198b825951218e74ab49bcfa15d980e"` [INFO] [stdout] 4abe8bb57e6d142de3695eb12d4d48769198b825951218e74ab49bcfa15d980e