[INFO] fetching crate zub 0.3.14...
[INFO] testing zub-0.3.14 against 1.49.0 for beta-1.50-1
[INFO] extracting crate zub 0.3.14 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate zub 0.3.14 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 zub 0.3.14
[INFO] finished tweaking crates.io crate zub 0.3.14
[INFO] tweaked toml for crates.io crate zub 0.3.14 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate crates.io crate zub 0.3.14 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 9294a862898de94d6597bcad370dfb71af526e13679876515ba681303c5470ee
[INFO] running `Command { std: "docker" "start" "-a" "9294a862898de94d6597bcad370dfb71af526e13679876515ba681303c5470ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9294a862898de94d6597bcad370dfb71af526e13679876515ba681303c5470ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9294a862898de94d6597bcad370dfb71af526e13679876515ba681303c5470ee", kill_on_drop: false }`
[INFO] [stdout] 9294a862898de94d6597bcad370dfb71af526e13679876515ba681303c5470ee
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] 2f917bcbc25284104065f492301b26faa47e4bb71cc6d36bf105d38c99b34008
[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" "2f917bcbc25284104065f492301b26faa47e4bb71cc6d36bf105d38c99b34008", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]    Compiling libc v0.2.69
[INFO] [stderr]    Compiling ryu v1.0.4
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling itoa v0.4.5
[INFO] [stderr]    Compiling version_check v0.9.1
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling lazy_static v0.2.11
[INFO] [stderr]    Compiling ahash v0.3.3
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]    Compiling bitmaps v2.1.0
[INFO] [stderr]    Compiling rand_xoshiro v0.4.0
[INFO] [stderr]    Compiling im-rc v14.3.0
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling thread-id v3.3.0
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling quote v1.0.4
[INFO] [stderr]    Compiling colored v1.9.3
[INFO] [stderr]    Compiling sized-chunks v0.5.3
[INFO] [stderr]    Compiling serde_json v1.0.52
[INFO] [stderr]    Compiling serde_derive v1.0.106
[INFO] [stderr]    Compiling flame v0.2.2
[INFO] [stderr]    Compiling flamer v0.3.0
[INFO] [stderr]    Compiling zub v0.3.14 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(vec_drain_as_slice)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/lib.rs:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #[macro_use] extern crate flamer;
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `tag::*`
[INFO] [stdout]  --> src/vm/value/object.rs:1:28
[INFO] [stdout]   |
[INFO] [stdout] 1 | use super::super::gc::{ *, tag::*, trace::* };
[INFO] [stdout]   |                            ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::compiler::CompileState`
[INFO] [stdout]   --> src/vm/vm.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | use super::compiler::CompileState;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Trace`, `Tracer`
[INFO] [stdout]  --> src/vm/disassembler.rs:2:18
[INFO] [stdout]   |
[INFO] [stdout] 2 | use gc::trace::{ Trace, Tracer };
[INFO] [stdout]   |                  ^^^^^  ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `zub`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "2f917bcbc25284104065f492301b26faa47e4bb71cc6d36bf105d38c99b34008", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2f917bcbc25284104065f492301b26faa47e4bb71cc6d36bf105d38c99b34008", kill_on_drop: false }`
[INFO] [stdout] 2f917bcbc25284104065f492301b26faa47e4bb71cc6d36bf105d38c99b34008