[INFO] fetching crate mamba 0.3.0...
[INFO] testing mamba-0.3.0 against 1.54.0 for beta-1.55-1
[INFO] extracting crate mamba 0.3.0 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate mamba 0.3.0 on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate mamba 0.3.0
[INFO] finished tweaking crates.io crate mamba 0.3.0
[INFO] tweaked toml for crates.io crate mamba 0.3.0 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate crates.io crate mamba 0.3.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 3c3134cd127ea93908c6094b879b4e923c8ead6a1a3809b4187a2f45dd865749
[INFO] running `Command { std: "docker" "start" "-a" "3c3134cd127ea93908c6094b879b4e923c8ead6a1a3809b4187a2f45dd865749", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3c3134cd127ea93908c6094b879b4e923c8ead6a1a3809b4187a2f45dd865749", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3c3134cd127ea93908c6094b879b4e923c8ead6a1a3809b4187a2f45dd865749", kill_on_drop: false }`
[INFO] [stdout] 3c3134cd127ea93908c6094b879b4e923c8ead6a1a3809b4187a2f45dd865749
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ebf1386c2696d7735474650c70c5027bfa63ce6ecc4cf19638b051e778debcca
[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" "ebf1386c2696d7735474650c70c5027bfa63ce6ecc4cf19638b051e778debcca", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.66
[INFO] [stderr]    Compiling proc-macro2 v1.0.7
[INFO] [stderr]    Compiling unicode-xid v0.2.0
[INFO] [stderr]    Compiling syn v1.0.13
[INFO] [stderr]    Compiling memchr v2.2.1
[INFO] [stderr]    Compiling serde v1.0.104
[INFO] [stderr]    Compiling version_check v0.1.5
[INFO] [stderr]    Compiling ryu v1.0.2
[INFO] [stderr]    Compiling ppv-lite86 v0.2.6
[INFO] [stderr]    Compiling itoa v0.4.4
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling predicates-core v1.0.0
[INFO] [stderr]    Compiling escargot v0.3.1
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling treeline v0.1.0
[INFO] [stderr]    Compiling unicode-width v0.1.7
[INFO] [stderr]    Compiling bytecount v0.3.2
[INFO] [stderr]    Compiling difference v2.0.0
[INFO] [stderr]    Compiling yaml-rust v0.3.5
[INFO] [stderr]    Compiling ansi_term v0.11.0
[INFO] [stderr]    Compiling strsim v0.8.0
[INFO] [stderr]    Compiling ansi_term v0.12.1
[INFO] [stderr]    Compiling unicode_names2 v0.2.2
[INFO] [stderr]    Compiling vec_map v0.8.1
[INFO] [stderr]    Compiling wtf8 v0.0.3
[INFO] [stderr]    Compiling remove_dir_all v0.5.2
[INFO] [stderr]    Compiling glob v0.3.0
[INFO] [stderr]    Compiling pathdiff v0.1.0
[INFO] [stderr]    Compiling num-traits v0.2.10
[INFO] [stderr]    Compiling num-integer v0.1.41
[INFO] [stderr]    Compiling num-bigint v0.2.4
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr]    Compiling predicates-tree v1.0.0
[INFO] [stderr]    Compiling predicates v1.0.2
[INFO] [stderr]    Compiling itertools v0.8.2
[INFO] [stderr]    Compiling c2-chacha v0.2.3
[INFO] [stderr]    Compiling nom v4.2.3
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling clap v2.33.0
[INFO] [stderr]    Compiling loggerv v0.7.2
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling nom_locate v0.3.1
[INFO] [stderr]    Compiling tempfile v3.1.0
[INFO] [stderr]    Compiling python-parser v0.1.0
[INFO] [stderr]    Compiling serde_derive v1.0.104
[INFO] [stderr]    Compiling serde_json v1.0.44
[INFO] [stderr]    Compiling assert_cmd v0.10.2
[INFO] [stderr]    Compiling mamba v0.3.0 (/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(drain_filter)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary trailing semicolon
[INFO] [stdout]   --> src/check/constrain/unify/expression/substitute.rs:33:10
[INFO] [stdout]    |
[INFO] [stdout] 33 |         };
[INFO] [stdout]    |          ^ help: remove this semicolon
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(redundant_semicolons)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lex/token.rs:139:9
[INFO] [stdout]     |
[INFO] [stdout] 139 | /         (match self {
[INFO] [stdout] 140 | |             Token::Id(id) => id.len(),
[INFO] [stdout] 141 | |             Token::Real(real) => real.len(),
[INFO] [stdout] 142 | |             Token::Int(int) => int.len(),
[INFO] [stdout] ...   |
[INFO] [stdout] 148 | |             other => format!("{}", other).len()
[INFO] [stdout] 149 | |         } as i32)
[INFO] [stdout]     | |_________________^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 139 |         match self {
[INFO] [stdout] 140 |             Token::Id(id) => id.len(),
[INFO] [stdout] 141 |             Token::Real(real) => real.len(),
[INFO] [stdout] 142 |             Token::Int(int) => int.len(),
[INFO] [stdout] 143 |             Token::Bool(true) => 4,
[INFO] [stdout] 144 |             Token::Bool(false) => 5,
[INFO] [stdout]   ...
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary trailing semicolon
[INFO] [stdout]   --> src/parse/definition.rs:25:6
[INFO] [stdout]    |
[INFO] [stdout] 25 |     };
[INFO] [stdout]    |      ^ help: remove this semicolon
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 3 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 `mamba`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "ebf1386c2696d7735474650c70c5027bfa63ce6ecc4cf19638b051e778debcca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ebf1386c2696d7735474650c70c5027bfa63ce6ecc4cf19638b051e778debcca", kill_on_drop: false }`
[INFO] [stdout] ebf1386c2696d7735474650c70c5027bfa63ce6ecc4cf19638b051e778debcca
