[INFO] fetching crate libmcs 0.1.0...
[INFO] testing libmcs-0.1.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate libmcs 0.1.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate libmcs 0.1.0 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate libmcs 0.1.0
[INFO] finished tweaking crates.io crate libmcs 0.1.0
[INFO] tweaked toml for crates.io crate libmcs 0.1.0 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4338a91d583c72de01466fd72244b24e60a673fa5da2246c0e9a8fb172f9f7cc
[INFO] running `Command { std: "docker" "start" "-a" "4338a91d583c72de01466fd72244b24e60a673fa5da2246c0e9a8fb172f9f7cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4338a91d583c72de01466fd72244b24e60a673fa5da2246c0e9a8fb172f9f7cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4338a91d583c72de01466fd72244b24e60a673fa5da2246c0e9a8fb172f9f7cc", kill_on_drop: false }`
[INFO] [stdout] 4338a91d583c72de01466fd72244b24e60a673fa5da2246c0e9a8fb172f9f7cc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 581d98c62682ae0e86f653c0f415e0952f53bfb98bac2645e6a11bb93d15b0e2
[INFO] running `Command { std: "docker" "start" "-a" "581d98c62682ae0e86f653c0f415e0952f53bfb98bac2645e6a11bb93d15b0e2", kill_on_drop: false }`
[INFO] [stderr]    Compiling libmcs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]   --> src/lib.rs:15:12
[INFO] [stdout]    |
[INFO] [stdout] 15 | #![feature(optin_builtin_traits)]
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^^^^ feature has been removed
[INFO] [stdout]    |
[INFO] [stdout]    = note: renamed to `auto_traits`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]   --> src/lib.rs:16:12
[INFO] [stdout]    |
[INFO] [stdout] 16 | #![feature(const_fn)]
[INFO] [stdout]    |            ^^^^^^^^ feature has been removed
[INFO] [stdout]    |
[INFO] [stdout]    = note: split into finer-grained feature gates
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:15:1
[INFO] [stdout]    |
[INFO] [stdout] 15 | #![feature(optin_builtin_traits)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:16:1
[INFO] [stdout]    |
[INFO] [stdout] 16 | #![feature(const_fn)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: negative trait bounds are not yet fully implemented; use marker types for now
[INFO] [stdout]    --> src/mcs.rs:131:21
[INFO] [stdout]     |
[INFO] [stdout] 131 | impl<'a, T: ?Sized> !marker::Send for MutexGuard<'a, T> { }
[INFO] [stdout]     |                     ^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: see issue #68318 <https://github.com/rust-lang/rust/issues/68318> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated associated function `std::sync::atomic::AtomicPtr::<T>::compare_and_swap`: Use `compare_exchange` or `compare_exchange_weak` instead
[INFO] [stdout]    --> src/mcs.rs:173:43
[INFO] [stdout]     |
[INFO] [stdout] 173 |                 let prev_tail = self.tail.compare_and_swap(prev, node, Acquire);
[INFO] [stdout]     |                                           ^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated associated function `std::sync::atomic::AtomicPtr::<T>::compare_and_swap`: Use `compare_exchange` or `compare_exchange_weak` instead
[INFO] [stdout]    --> src/mcs.rs:281:36
[INFO] [stdout]     |
[INFO] [stdout] 281 |                 if self.__mtx.tail.compare_and_swap(raw_node_ptr, ptr::null_mut(), Release) == raw_node_ptr {
[INFO] [stdout]     |                                    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 5 previous errors; 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0557, E0658.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `libmcs` due to 6 previous errors; 2 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "581d98c62682ae0e86f653c0f415e0952f53bfb98bac2645e6a11bb93d15b0e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "581d98c62682ae0e86f653c0f415e0952f53bfb98bac2645e6a11bb93d15b0e2", kill_on_drop: false }`
[INFO] [stdout] 581d98c62682ae0e86f653c0f415e0952f53bfb98bac2645e6a11bb93d15b0e2