[INFO] cloning repository https://github.com/Cerulity64X/two_mutable_refs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Cerulity64X/two_mutable_refs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCerulity64X%2Ftwo_mutable_refs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCerulity64X%2Ftwo_mutable_refs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d69ccd41fef2dd1ef0de18d32fed77d0a56d5a4a
[INFO] checking Cerulity64X/two_mutable_refs against 1.95.0 for pr-155915
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCerulity64X%2Ftwo_mutable_refs" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/Cerulity64X/two_mutable_refs
[INFO] finished tweaking git repo https://github.com/Cerulity64X/two_mutable_refs
[INFO] tweaked toml for git repo https://github.com/Cerulity64X/two_mutable_refs written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/Cerulity64X/two_mutable_refs on toolchain 1.95.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/Cerulity64X/two_mutable_refs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/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" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] efa0215109328dcf01dd612a614fdcbf0b1304b9412bcb910c62a91f0e247dbe
[INFO] running `Command { std: "docker" "start" "-a" "efa0215109328dcf01dd612a614fdcbf0b1304b9412bcb910c62a91f0e247dbe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "efa0215109328dcf01dd612a614fdcbf0b1304b9412bcb910c62a91f0e247dbe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "efa0215109328dcf01dd612a614fdcbf0b1304b9412bcb910c62a91f0e247dbe", kill_on_drop: false }`
[INFO] [stdout] efa0215109328dcf01dd612a614fdcbf0b1304b9412bcb910c62a91f0e247dbe
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/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" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d8b738166365a6d27b8107aaef4c49afa9dbed454f1423e662fd795d30005409
[INFO] running `Command { std: "docker" "start" "-a" "d8b738166365a6d27b8107aaef4c49afa9dbed454f1423e662fd795d30005409", kill_on_drop: false }`
[INFO] [stderr]     Checking two_mutable_refs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(get_mut_unchecked)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::rc::Rc`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::rc::Rc;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/no_print.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     for i in 0..ref_count {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(get_mut_unchecked)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::rc::Rc`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::rc::Rc;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `two_mutable_refs` (bin "two_mutable_refs") due to 1 previous error; 2 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/no_print.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     for i in 0..ref_count {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `two_mutable_refs` (bin "two_mutable_refs" test) due to 1 previous error; 2 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "d8b738166365a6d27b8107aaef4c49afa9dbed454f1423e662fd795d30005409", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d8b738166365a6d27b8107aaef4c49afa9dbed454f1423e662fd795d30005409", kill_on_drop: false }`
[INFO] [stdout] d8b738166365a6d27b8107aaef4c49afa9dbed454f1423e662fd795d30005409
