[INFO] fetching crate components-arena 1.1.1...
[INFO] testing components-arena-1.1.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate components-arena 1.1.1 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate components-arena 1.1.1 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate components-arena 1.1.1
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate components-arena 1.1.1
[INFO] tweaked toml for crates.io crate components-arena 1.1.1 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate crates.io crate components-arena 1.1.1 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b7483959d179c8a03a9f7ae65bfe16a2f35ab38a42986691c94aabd9f9e4ded5
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "b7483959d179c8a03a9f7ae65bfe16a2f35ab38a42986691c94aabd9f9e4ded5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b7483959d179c8a03a9f7ae65bfe16a2f35ab38a42986691c94aabd9f9e4ded5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b7483959d179c8a03a9f7ae65bfe16a2f35ab38a42986691c94aabd9f9e4ded5", kill_on_drop: false }`
[INFO] [stdout] b7483959d179c8a03a9f7ae65bfe16a2f35ab38a42986691c94aabd9f9e4ded5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 89107ffe3d2e59432ca7da4249073096d7b5c3e2b650b8149621c72cc8d7b42a
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "89107ffe3d2e59432ca7da4249073096d7b5c3e2b650b8149621c72cc8d7b42a", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.23
[INFO] [stderr]    Compiling libc v0.2.77
[INFO] [stderr]    Compiling syn v1.0.42
[INFO] [stderr]    Compiling generics v0.2.5
[INFO] [stderr]    Compiling num-bigint v0.3.0
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling getrandom v0.1.15
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling rand_pcg v0.2.1
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling enum-ordinalize v3.1.8
[INFO] [stderr]    Compiling educe v0.4.13
[INFO] [stderr]    Compiling phantom-type v0.3.0
[INFO] [stderr]    Compiling components-arena v1.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:52
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(all(feature="nightly", feature="std"), feature(const_fn))]
[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:3:52
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![cfg_attr(all(feature="nightly", feature="std"), feature(const_fn_fn_ptr_basics))]
[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:5:32
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![cfg_attr(feature="nightly", feature(shrink_to))]
[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:6:32
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![cfg_attr(feature="nightly", feature(try_reserve))]
[INFO] [stdout]   |                                ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `components-arena`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "89107ffe3d2e59432ca7da4249073096d7b5c3e2b650b8149621c72cc8d7b42a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "89107ffe3d2e59432ca7da4249073096d7b5c3e2b650b8149621c72cc8d7b42a", kill_on_drop: false }`
[INFO] [stdout] 89107ffe3d2e59432ca7da4249073096d7b5c3e2b650b8149621c72cc8d7b42a