[INFO] cloning repository https://github.com/myelin-ai/engine
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/myelin-ai/engine" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmyelin-ai%2Fengine", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmyelin-ai%2Fengine'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0457e868357cef6916418e9674807b6988414444
[INFO] testing myelin-ai/engine against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmyelin-ai%2Fengine" "/workspace/builds/worker-0/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/myelin-ai/engine 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 git repo https://github.com/myelin-ai/engine
[INFO] finished tweaking git repo https://github.com/myelin-ai/engine
[INFO] tweaked toml for git repo https://github.com/myelin-ai/engine written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/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] 063a6ea3b023f2a56f1ee16cfaa12e608593b88e848ed161cb0a697ec241836b
[INFO] running `Command { std: "docker" "start" "-a" "063a6ea3b023f2a56f1ee16cfaa12e608593b88e848ed161cb0a697ec241836b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "063a6ea3b023f2a56f1ee16cfaa12e608593b88e848ed161cb0a697ec241836b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "063a6ea3b023f2a56f1ee16cfaa12e608593b88e848ed161cb0a697ec241836b", kill_on_drop: false }`
[INFO] [stdout] 063a6ea3b023f2a56f1ee16cfaa12e608593b88e848ed161cb0a697ec241836b
[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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ce20f8acb14b9e65e8a2f8d26bc46c3c89f2dbc17c6b768c58a676196b9d87ae
[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" "ce20f8acb14b9e65e8a2f8d26bc46c3c89f2dbc17c6b768c58a676196b9d87ae", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling syn v1.0.58
[INFO] [stderr]    Compiling serde_derive v1.0.118
[INFO] [stderr]    Compiling fixedbitset v0.1.9
[INFO] [stderr]    Compiling ordermap v0.3.5
[INFO] [stderr]    Compiling serde v1.0.118
[INFO] [stderr]    Compiling slotmap v0.3.0
[INFO] [stderr]    Compiling nameof v1.2.1
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-complex v0.2.4
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling matrixmultiply v0.2.4
[INFO] [stderr]    Compiling generational-arena v0.2.8
[INFO] [stderr]    Compiling generic-array v0.12.3
[INFO] [stderr]    Compiling smallvec v0.6.13
[INFO] [stderr]    Compiling petgraph v0.4.13
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling time v0.1.44
[INFO] [stderr]    Compiling approx v0.3.2
[INFO] [stderr]    Compiling num-rational v0.2.4
[INFO] [stderr]    Compiling alga v0.9.3
[INFO] [stderr]    Compiling nalgebra v0.18.1
[INFO] [stderr]    Compiling ncollide2d v0.20.1
[INFO] [stderr]    Compiling myelin-geometry v2.4.1
[INFO] [stderr]    Compiling nphysics2d v0.12.3
[INFO] [stderr]    Compiling myelin-engine v0.14.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(specialization)]
[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:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(non_exhaustive)]
[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:7:1
[INFO] [stdout]   |
[INFO] [stdout] 7 | #![feature(box_syntax)]
[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:8:1
[INFO] [stdout]   |
[INFO] [stdout] 8 | #![feature(trait_alias)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/lib.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(specialization)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]   = help: consider using `min_specialization` instead, which is more stable and complete
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 previous errors; 1 warning 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 `myelin-engine`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "ce20f8acb14b9e65e8a2f8d26bc46c3c89f2dbc17c6b768c58a676196b9d87ae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ce20f8acb14b9e65e8a2f8d26bc46c3c89f2dbc17c6b768c58a676196b9d87ae", kill_on_drop: false }`
[INFO] [stdout] ce20f8acb14b9e65e8a2f8d26bc46c3c89f2dbc17c6b768c58a676196b9d87ae