[INFO] updating cached repository https://github.com/learn-you-a-rust/references
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/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] 6ff4ef6f42c370e58278100c0a8e74b01e4b82a9
[INFO] testing learn-you-a-rust/references against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Freferences" "work/builds/worker-3/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/learn-you-a-rust/references on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/learn-you-a-rust/references
[INFO] finished tweaking git repo https://github.com/learn-you-a-rust/references
[INFO] tweaked toml for git repo https://github.com/learn-you-a-rust/references written to work/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/learn-you-a-rust/references already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] 0432ab6ae212ecc56fce2b30829538bea431221b2e038489a67c957f52d9b852
[INFO] running `"docker" "start" "-a" "0432ab6ae212ecc56fce2b30829538bea431221b2e038489a67c957f52d9b852"`
[INFO] [stderr]    Compiling references v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `s4`
[INFO] [stderr]   --> src/main.rs:19:9
[INFO] [stderr]    |
[INFO] [stderr] 19 |     let s4 = &s1;        // <-- if this ref exists, &mut s1 refs can't be used 
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_s4`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s2`
[INFO] [stderr]   --> src/main.rs:31:13
[INFO] [stderr]    |
[INFO] [stderr] 31 |         let s2 = &mut s1;
[INFO] [stderr]    |             ^^ help: consider prefixing with an underscore: `_s2`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `reference_to_nothing`
[INFO] [stderr]   --> src/main.rs:45:9
[INFO] [stderr]    |
[INFO] [stderr] 45 |     let reference_to_nothing = no_dangle();
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_reference_to_nothing`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `some_string`
[INFO] [stderr]   --> src/main.rs:65:11
[INFO] [stderr]    |
[INFO] [stderr] 65 | fn change(some_string: &String) {
[INFO] [stderr]    |           ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_string`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `change`
[INFO] [stderr]   --> src/main.rs:65:1
[INFO] [stderr]    |
[INFO] [stderr] 65 | fn change(some_string: &String) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.44s
[INFO] running `"docker" "inspect" "0432ab6ae212ecc56fce2b30829538bea431221b2e038489a67c957f52d9b852"`
[INFO] running `"docker" "rm" "-f" "0432ab6ae212ecc56fce2b30829538bea431221b2e038489a67c957f52d9b852"`
[INFO] [stdout] 0432ab6ae212ecc56fce2b30829538bea431221b2e038489a67c957f52d9b852
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "+1.38.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] b786a69daa214c8bae6cba922c12347a72f57d83596f9cf538484fdb4cbedd62
[INFO] running `"docker" "start" "-a" "b786a69daa214c8bae6cba922c12347a72f57d83596f9cf538484fdb4cbedd62"`
[INFO] [stderr]    Compiling references v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `s4`
[INFO] [stderr]   --> src/main.rs:19:9
[INFO] [stderr]    |
[INFO] [stderr] 19 |     let s4 = &s1;        // <-- if this ref exists, &mut s1 refs can't be used 
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_s4`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s2`
[INFO] [stderr]   --> src/main.rs:31:13
[INFO] [stderr]    |
[INFO] [stderr] 31 |         let s2 = &mut s1;
[INFO] [stderr]    |             ^^ help: consider prefixing with an underscore: `_s2`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `reference_to_nothing`
[INFO] [stderr]   --> src/main.rs:45:9
[INFO] [stderr]    |
[INFO] [stderr] 45 |     let reference_to_nothing = no_dangle();
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_reference_to_nothing`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `some_string`
[INFO] [stderr]   --> src/main.rs:65:11
[INFO] [stderr]    |
[INFO] [stderr] 65 | fn change(some_string: &String) {
[INFO] [stderr]    |           ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_string`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `change`
[INFO] [stderr]   --> src/main.rs:65:1
[INFO] [stderr]    |
[INFO] [stderr] 65 | fn change(some_string: &String) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.39s
[INFO] running `"docker" "inspect" "b786a69daa214c8bae6cba922c12347a72f57d83596f9cf538484fdb4cbedd62"`
[INFO] running `"docker" "rm" "-f" "b786a69daa214c8bae6cba922c12347a72f57d83596f9cf538484fdb4cbedd62"`
[INFO] [stdout] b786a69daa214c8bae6cba922c12347a72f57d83596f9cf538484fdb4cbedd62
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "+1.38.0" "test" "--frozen"`
[INFO] [stdout] 5982338fa7289535ebc0800d64a1a7e39e2fa7badcde5fdcd674ae9e605adf57
[INFO] running `"docker" "start" "-a" "5982338fa7289535ebc0800d64a1a7e39e2fa7badcde5fdcd674ae9e605adf57"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.00s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/references-5118cfd380a86567
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "5982338fa7289535ebc0800d64a1a7e39e2fa7badcde5fdcd674ae9e605adf57"`
[INFO] running `"docker" "rm" "-f" "5982338fa7289535ebc0800d64a1a7e39e2fa7badcde5fdcd674ae9e605adf57"`
[INFO] [stdout] 5982338fa7289535ebc0800d64a1a7e39e2fa7badcde5fdcd674ae9e605adf57