[INFO] fetching crate mamba 0.3.0...
[INFO] testing mamba-0.3.0 against 1.60.0 for beta-1.61-1
[INFO] extracting crate mamba 0.3.0 into /workspace/builds/worker-100/source
[INFO] validating manifest of crates.io crate mamba 0.3.0 on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "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-100/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" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded wtf8 v0.0.3
[INFO] [stderr]   Downloaded proc-macro2 v1.0.7
[INFO] [stderr]   Downloaded num-bigint v0.2.4
[INFO] [stderr]   Downloaded num-traits v0.2.10
[INFO] [stderr]   Downloaded unicode_names2 v0.2.2
[INFO] [stderr]   Downloaded hermit-abi v0.1.6
[INFO] [stderr]   Downloaded syn v1.0.13
[INFO] [stderr]   Downloaded predicates v1.0.2
[INFO] [stderr]   Downloaded loggerv v0.7.2
[INFO] [stderr]   Downloaded bytecount v0.3.2
[INFO] [stderr]   Downloaded nom_locate v0.3.1
[INFO] [stderr]   Downloaded python-parser v0.1.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-100/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-100/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5b941ed071812bcd7c0904a5e69de45b47134e50ab31fe0f205317088313b1f8
[INFO] running `Command { std: "docker" "start" "-a" "5b941ed071812bcd7c0904a5e69de45b47134e50ab31fe0f205317088313b1f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5b941ed071812bcd7c0904a5e69de45b47134e50ab31fe0f205317088313b1f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b941ed071812bcd7c0904a5e69de45b47134e50ab31fe0f205317088313b1f8", kill_on_drop: false }`
[INFO] [stdout] 5b941ed071812bcd7c0904a5e69de45b47134e50ab31fe0f205317088313b1f8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-100/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-100/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f78ff7b2118247ef91e24735a717cf7952761a762fa2afc8d1374d2504d0107a
[INFO] running `Command { std: "docker" "start" "-a" "f78ff7b2118247ef91e24735a717cf7952761a762fa2afc8d1374d2504d0107a", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling autocfg v0.1.7
[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 getrandom v0.1.14
[INFO] [stderr]    Compiling ryu v1.0.2
[INFO] [stderr]    Compiling memchr v2.2.1
[INFO] [stderr]    Compiling version_check v0.1.5
[INFO] [stderr]    Compiling serde v1.0.104
[INFO] [stderr]    Compiling ppv-lite86 v0.2.6
[INFO] [stderr]    Compiling predicates-core v1.0.0
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling itoa v0.4.4
[INFO] [stderr]    Compiling escargot v0.3.1
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling bytecount v0.3.2
[INFO] [stderr]    Compiling unicode-width v0.1.7
[INFO] [stderr]    Compiling treeline v0.1.0
[INFO] [stderr]    Compiling yaml-rust v0.3.5
[INFO] [stderr]    Compiling wtf8 v0.0.3
[INFO] [stderr]    Compiling either v1.5.3
[INFO] [stderr]    Compiling unicode_names2 v0.2.2
[INFO] [stderr]    Compiling vec_map v0.8.1
[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 textwrap v0.11.0
[INFO] [stderr]    Compiling predicates v1.0.2
[INFO] [stderr]    Compiling itertools v0.8.2
[INFO] [stderr]    Compiling predicates-tree v1.0.0
[INFO] [stderr]    Compiling c2-chacha v0.2.3
[INFO] [stderr]    Compiling nom v4.2.3
[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 atty v0.2.14
[INFO] [stderr]    Compiling clap v2.33.0
[INFO] [stderr]    Compiling loggerv v0.7.2
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling nom_locate v0.3.1
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling python-parser v0.1.0
[INFO] [stderr]    Compiling tempfile v3.1.0
[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] 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 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[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(drain_filter)]
[INFO] [stdout]   |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 2 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` due to 2 previous errors; 2 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "f78ff7b2118247ef91e24735a717cf7952761a762fa2afc8d1374d2504d0107a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f78ff7b2118247ef91e24735a717cf7952761a762fa2afc8d1374d2504d0107a", kill_on_drop: false }`
[INFO] [stdout] f78ff7b2118247ef91e24735a717cf7952761a762fa2afc8d1374d2504d0107a