[INFO] fetching crate rebar 0.0.1...
[INFO] checking rebar-0.0.1 against beta for pr-78714
[INFO] extracting crate rebar 0.0.1 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate rebar 0.0.1 on toolchain beta
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate rebar 0.0.1
[INFO] finished tweaking crates.io crate rebar 0.0.1
[INFO] tweaked toml for crates.io crate rebar 0.0.1 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f006b7d1d3d3b42fb492cada9370e768440650df73bec754a9cb54d784ab2e20
[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" "f006b7d1d3d3b42fb492cada9370e768440650df73bec754a9cb54d784ab2e20", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f006b7d1d3d3b42fb492cada9370e768440650df73bec754a9cb54d784ab2e20", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f006b7d1d3d3b42fb492cada9370e768440650df73bec754a9cb54d784ab2e20", kill_on_drop: false }`
[INFO] [stdout] f006b7d1d3d3b42fb492cada9370e768440650df73bec754a9cb54d784ab2e20
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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=forbid" "-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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9ebd0a9e8819604bd45f2d7663ca8d94d6cea3ec53eefc844f01b90c445397b4
[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" "9ebd0a9e8819604bd45f2d7663ca8d94d6cea3ec53eefc844f01b90c445397b4", kill_on_drop: false }`
[INFO] [stderr]     Checking dirs-sys v0.3.5
[INFO] [stderr]     Checking dirs v2.0.2
[INFO] [stderr]     Checking term v0.6.1
[INFO] [stderr]     Checking rebar v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(collections)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(collections)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no function or associated item named `from_str` found for struct `String` in the current scope
[INFO] [stdout]   --> src/lib.rs:25:28
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let mut line = String::from_str("\r");
[INFO] [stdout]    |                            ^^^^^^^^ function or associated item not found in `String`
[INFO] [stdout]    |
[INFO] [stdout]    = help: items from traits can only be used if the trait is in scope
[INFO] [stdout] help: the following trait is implemented but not in scope; perhaps add a `use` for it:
[INFO] [stdout]    |
[INFO] [stdout] 4  | use std::str::FromStr;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no function or associated item named `from_str` found for struct `String` in the current scope
[INFO] [stdout]   --> src/lib.rs:25:28
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let mut line = String::from_str("\r");
[INFO] [stdout]    |                            ^^^^^^^^ function or associated item not found in `String`
[INFO] [stdout]    |
[INFO] [stdout]    = help: items from traits can only be used if the trait is in scope
[INFO] [stdout] help: the following trait is implemented but not in scope; perhaps add a `use` for it:
[INFO] [stdout]    |
[INFO] [stdout] 4  | use std::str::FromStr;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0599.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0599.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rebar`
[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" "9ebd0a9e8819604bd45f2d7663ca8d94d6cea3ec53eefc844f01b90c445397b4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9ebd0a9e8819604bd45f2d7663ca8d94d6cea3ec53eefc844f01b90c445397b4", kill_on_drop: false }`
[INFO] [stdout] 9ebd0a9e8819604bd45f2d7663ca8d94d6cea3ec53eefc844f01b90c445397b4