[INFO] cloning repository https://github.com/pasindumuth/rUniversalDB
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/pasindumuth/rUniversalDB" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpasindumuth%2FrUniversalDB", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpasindumuth%2FrUniversalDB'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 47e5333f7353bba286d54d6b56238fd0dc99b9e4
[INFO] testing pasindumuth/rUniversalDB against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpasindumuth%2FrUniversalDB" "/workspace/builds/worker-9/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-9/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/pasindumuth/rUniversalDB 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/pasindumuth/rUniversalDB
[INFO] finished tweaking git repo https://github.com/pasindumuth/rUniversalDB
[INFO] tweaked toml for git repo https://github.com/pasindumuth/rUniversalDB written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate git repo https://github.com/pasindumuth/rUniversalDB 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-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] 2e3bb56da0c3b6476c4cdc65c5cd8cc888b726cff5cf09fc8967014242733ea6
[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" "2e3bb56da0c3b6476c4cdc65c5cd8cc888b726cff5cf09fc8967014242733ea6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2e3bb56da0c3b6476c4cdc65c5cd8cc888b726cff5cf09fc8967014242733ea6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2e3bb56da0c3b6476c4cdc65c5cd8cc888b726cff5cf09fc8967014242733ea6", kill_on_drop: false }`
[INFO] [stdout] 2e3bb56da0c3b6476c4cdc65c5cd8cc888b726cff5cf09fc8967014242733ea6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] e6293bc43317a4570894c9773fab850bd4e5e1a8de982b2fd241dd25457cdcfe
[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" "e6293bc43317a4570894c9773fab850bd4e5e1a8de982b2fd241dd25457cdcfe", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.52
[INFO] [stderr]    Compiling cactus v1.0.6
[INFO] [stderr]    Compiling vob v2.0.5
[INFO] [stderr]    Compiling filetime v0.2.13
[INFO] [stderr]    Compiling rmp v0.8.9
[INFO] [stderr]    Compiling chrono v0.4.19
[INFO] [stderr]    Compiling rand_xorshift v0.2.0
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling vergen v3.1.0
[INFO] [stderr]    Compiling lrpar v0.9.2
[INFO] [stderr]    Compiling serde_derive v1.0.117
[INFO] [stderr]    Compiling serde v1.0.117
[INFO] [stderr]    Compiling packedvec v1.2.2
[INFO] [stderr]    Compiling bincode v1.3.1
[INFO] [stderr]    Compiling rmp-serde v0.14.4
[INFO] [stderr]    Compiling sparsevec v0.1.3
[INFO] [stderr]    Compiling cfgrammar v0.9.2
[INFO] [stderr]    Compiling lrtable v0.9.2
[INFO] [stderr]    Compiling lrlex v0.9.2
[INFO] [stderr]    Compiling runiversal v0.1.0 (/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(map_first_last)]
[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 `runiversal`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "e6293bc43317a4570894c9773fab850bd4e5e1a8de982b2fd241dd25457cdcfe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e6293bc43317a4570894c9773fab850bd4e5e1a8de982b2fd241dd25457cdcfe", kill_on_drop: false }`
[INFO] [stdout] e6293bc43317a4570894c9773fab850bd4e5e1a8de982b2fd241dd25457cdcfe