[INFO] fetching crate fk_std 0.2.3...
[INFO] testing fk_std-0.2.3 against 1.49.0 for beta-1.50-1
[INFO] extracting crate fk_std 0.2.3 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate fk_std 0.2.3 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 crates.io crate fk_std 0.2.3
[INFO] finished tweaking crates.io crate fk_std 0.2.3
[INFO] tweaked toml for crates.io crate fk_std 0.2.3 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate crates.io crate fk_std 0.2.3 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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 5d16a828e39fba6488d7606c439537de2b8d12384c48f8f27bb395b098d379aa
[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" "5d16a828e39fba6488d7606c439537de2b8d12384c48f8f27bb395b098d379aa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5d16a828e39fba6488d7606c439537de2b8d12384c48f8f27bb395b098d379aa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5d16a828e39fba6488d7606c439537de2b8d12384c48f8f27bb395b098d379aa", kill_on_drop: false }`
[INFO] [stdout] 5d16a828e39fba6488d7606c439537de2b8d12384c48f8f27bb395b098d379aa
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] fb4361badad3ac9c4a65da71493f3b5f8b08c43345bae0ce5e0c6d587108ecb5
[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" "fb4361badad3ac9c4a65da71493f3b5f8b08c43345bae0ce5e0c6d587108ecb5", kill_on_drop: false }`
[INFO] [stderr]    Compiling fk_std v0.2.3 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(lang_items, alloc)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `*`
[INFO] [stdout]  --> src/lib.rs:6:20
[INFO] [stdout]   |
[INFO] [stdout] 6 | use fkstd_errors::{*};
[INFO] [stdout]   |                    ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `fmt::format`
[INFO] [stdout]   --> src/lib.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 | use alloc::{fmt::format, string::String};
[INFO] [stdout]    |             ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `c_char` should have an upper camel case name
[INFO] [stdout]   --> src/lib.rs:14:10
[INFO] [stdout]    |
[INFO] [stdout] 14 | pub type c_char = i8;
[INFO] [stdout]    |          ^^^^^^ help: convert the identifier to upper camel case: `CChar`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `c_int` should have an upper camel case name
[INFO] [stdout]   --> src/lib.rs:15:10
[INFO] [stdout]    |
[INFO] [stdout] 15 | pub type c_int = i32;
[INFO] [stdout]    |          ^^^^^ help: convert the identifier to upper camel case: `CInt`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `fk_std`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "fb4361badad3ac9c4a65da71493f3b5f8b08c43345bae0ce5e0c6d587108ecb5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fb4361badad3ac9c4a65da71493f3b5f8b08c43345bae0ce5e0c6d587108ecb5", kill_on_drop: false }`
[INFO] [stdout] fb4361badad3ac9c4a65da71493f3b5f8b08c43345bae0ce5e0c6d587108ecb5