[INFO] cloning repository https://github.com/lfairy/weldyn
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/lfairy/weldyn" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flfairy%2Fweldyn", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flfairy%2Fweldyn'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8af1cf66e5bcb540f1dd03134a858d5eb08f875d
[INFO] testing lfairy/weldyn against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flfairy%2Fweldyn" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/lfairy/weldyn 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/lfairy/weldyn
[INFO] removed workspace from git repo https://github.com/lfairy/weldyn
[INFO] finished tweaking git repo https://github.com/lfairy/weldyn
[INFO] tweaked toml for git repo https://github.com/lfairy/weldyn written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/lfairy/weldyn 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-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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] a04dc965c09f6f1f79938baf69a3274da46c503eacb97b8c7751cc137e96c2d9
[INFO] running `Command { std: "docker" "start" "-a" "a04dc965c09f6f1f79938baf69a3274da46c503eacb97b8c7751cc137e96c2d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a04dc965c09f6f1f79938baf69a3274da46c503eacb97b8c7751cc137e96c2d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a04dc965c09f6f1f79938baf69a3274da46c503eacb97b8c7751cc137e96c2d9", kill_on_drop: false }`
[INFO] [stdout] a04dc965c09f6f1f79938baf69a3274da46c503eacb97b8c7751cc137e96c2d9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 9153413ffaa910ff5ac951c73424613dd91ebaa5912b55854eda1c6be8d06b36
[INFO] running `Command { std: "docker" "start" "-a" "9153413ffaa910ff5ac951c73424613dd91ebaa5912b55854eda1c6be8d06b36", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.58
[INFO] [stderr]    Compiling autocfg v0.1.4
[INFO] [stderr]    Compiling rand_core v0.4.0
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.16
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]    Compiling pin-utils v0.1.0-alpha.4
[INFO] [stderr]    Compiling lazy_static v1.3.0
[INFO] [stderr]    Compiling scopeguard v0.3.3
[INFO] [stderr]    Compiling futures v0.1.28
[INFO] [stderr]    Compiling stable_deref_trait v1.1.1
[INFO] [stderr]    Compiling arrayvec v0.4.10
[INFO] [stderr]    Compiling nodrop v0.1.13
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling memoffset v0.2.1
[INFO] [stderr]    Compiling syn v0.15.39
[INFO] [stderr]    Compiling async-datagram v3.0.0
[INFO] [stderr]    Compiling async-ready v3.0.0
[INFO] [stderr]    Compiling async-datagram v2.2.0
[INFO] [stderr]    Compiling log v0.4.6
[INFO] [stderr]    Compiling owning_ref v0.4.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/async-datagram-2.2.0/src/lib.rs:43:1
[INFO] [stdout]    |
[INFO] [stdout] 43 | #![feature(futures_api)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `async-datagram`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "9153413ffaa910ff5ac951c73424613dd91ebaa5912b55854eda1c6be8d06b36", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9153413ffaa910ff5ac951c73424613dd91ebaa5912b55854eda1c6be8d06b36", kill_on_drop: false }`
[INFO] [stdout] 9153413ffaa910ff5ac951c73424613dd91ebaa5912b55854eda1c6be8d06b36