[INFO] cloning repository https://github.com/liamzdenek/caption-reading-speed
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/liamzdenek/caption-reading-speed" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fliamzdenek%2Fcaption-reading-speed", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fliamzdenek%2Fcaption-reading-speed'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] a84e8e9d30011f974c05356b289bede388dde9b0
[INFO] testing liamzdenek/caption-reading-speed against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fliamzdenek%2Fcaption-reading-speed" "/workspace/builds/worker-101/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-101/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/liamzdenek/caption-reading-speed on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/liamzdenek/caption-reading-speed
[INFO] finished tweaking git repo https://github.com/liamzdenek/caption-reading-speed
[INFO] tweaked toml for git repo https://github.com/liamzdenek/caption-reading-speed written to /workspace/builds/worker-101/source/Cargo.toml
[INFO] crate git repo https://github.com/liamzdenek/caption-reading-speed already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded derive_builder v0.7.1
[INFO] [stderr]   Downloaded derive_builder_core v0.4.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-101/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-101/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a8f6942c92344b576327658437b68eb5ad8a9265cb6d9e214eea31c983f6f197
[INFO] running `Command { std: "docker" "start" "-a" "a8f6942c92344b576327658437b68eb5ad8a9265cb6d9e214eea31c983f6f197", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a8f6942c92344b576327658437b68eb5ad8a9265cb6d9e214eea31c983f6f197", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a8f6942c92344b576327658437b68eb5ad8a9265cb6d9e214eea31c983f6f197", kill_on_drop: false }`
[INFO] [stdout] a8f6942c92344b576327658437b68eb5ad8a9265cb6d9e214eea31c983f6f197
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-101/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-101/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8d6400716c9fa9dbd02fb7bba0128134fc72bafcbb16d731bd83e7481fec8a3b
[INFO] running `Command { std: "docker" "start" "-a" "8d6400716c9fa9dbd02fb7bba0128134fc72bafcbb16d731bd83e7481fec8a3b", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]    Compiling libc v0.2.55
[INFO] [stderr]    Compiling ident_case v1.0.1
[INFO] [stderr]    Compiling autocfg v0.1.4
[INFO] [stderr]    Compiling failure_derive v0.1.5
[INFO] [stderr]    Compiling rustc-demangle v0.1.14
[INFO] [stderr]    Compiling derive_builder v0.7.1
[INFO] [stderr]    Compiling backtrace-sys v0.1.28
[INFO] [stderr]    Compiling backtrace v0.3.26
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]    Compiling darling_core v0.8.6
[INFO] [stderr]    Compiling synstructure v0.10.2
[INFO] [stderr]    Compiling darling_macro v0.8.6
[INFO] [stderr]    Compiling failure v0.1.5
[INFO] [stderr]    Compiling darling v0.8.6
[INFO] [stderr]    Compiling derive_builder_core v0.4.1
[INFO] [stderr]    Compiling reading-speed v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(duration_float)]
[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 `reading-speed` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "8d6400716c9fa9dbd02fb7bba0128134fc72bafcbb16d731bd83e7481fec8a3b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8d6400716c9fa9dbd02fb7bba0128134fc72bafcbb16d731bd83e7481fec8a3b", kill_on_drop: false }`
[INFO] [stdout] 8d6400716c9fa9dbd02fb7bba0128134fc72bafcbb16d731bd83e7481fec8a3b