[INFO] fetching crate is_prime 1.0.5...
[INFO] testing is_prime-1.0.5 against 1.55.0 for beta-1.56-1
[INFO] extracting crate is_prime 1.0.5 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate is_prime 1.0.5 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 crates.io crate is_prime 1.0.5
[INFO] finished tweaking crates.io crate is_prime 1.0.5
[INFO] tweaked toml for crates.io crate is_prime 1.0.5 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--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-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] 0d2ace249cd521eab457beed956ad57760c4254677adcf8f5e13b364e4474024
[INFO] running `Command { std: "docker" "start" "-a" "0d2ace249cd521eab457beed956ad57760c4254677adcf8f5e13b364e4474024", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0d2ace249cd521eab457beed956ad57760c4254677adcf8f5e13b364e4474024", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0d2ace249cd521eab457beed956ad57760c4254677adcf8f5e13b364e4474024", kill_on_drop: false }`
[INFO] [stdout] 0d2ace249cd521eab457beed956ad57760c4254677adcf8f5e13b364e4474024
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] 02ff946010496bedde88a69ac8af5e36cd779b29d2b4c5e1b407bd988793dd21
[INFO] running `Command { std: "docker" "start" "-a" "02ff946010496bedde88a69ac8af5e36cd779b29d2b4c5e1b407bd988793dd21", kill_on_drop: false }`
[INFO] [stderr]    Compiling rustc-cfg v0.2.0
[INFO] [stderr]    Compiling ieee754 v0.2.6
[INFO] [stderr]    Compiling hamming v0.1.3
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-traits v0.1.43
[INFO] [stderr]    Compiling num-bigint v0.1.44
[INFO] [stderr]    Compiling ramp v0.5.9
[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/ramp-0.5.9/src/lib.rs:17:1
[INFO] [stdout]    |
[INFO] [stdout] 17 | #![feature(core_intrinsics, asm, allocator_api)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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/ramp-0.5.9/src/lib.rs:18:1
[INFO] [stdout]    |
[INFO] [stdout] 18 | #![feature(step_trait, step_trait_ext, ptr_internals, raw_vec_internals)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0199]: implementing the trait `Step` is not unsafe
[INFO] [stdout]     --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/ramp-0.5.9/src/int.rs:3697:1
[INFO] [stdout]      |
[INFO] [stdout] 3697 | / unsafe impl std::iter::Step for Int {
[INFO] [stdout] 3698 | |     fn steps_between(start: &Int, end: &Int) -> Option<usize> {
[INFO] [stdout] 3699 | |         let diff = (start - end).abs();
[INFO] [stdout] 3700 | |
[INFO] [stdout] ...    |
[INFO] [stdout] 3715 | |     }
[INFO] [stdout] 3716 | | }
[INFO] [stdout]      | |_^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0199, E0554.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0199`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `ramp` due to 4 previous errors
[INFO] running `Command { std: "docker" "inspect" "02ff946010496bedde88a69ac8af5e36cd779b29d2b4c5e1b407bd988793dd21", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "02ff946010496bedde88a69ac8af5e36cd779b29d2b4c5e1b407bd988793dd21", kill_on_drop: false }`
[INFO] [stdout] 02ff946010496bedde88a69ac8af5e36cd779b29d2b4c5e1b407bd988793dd21