[INFO] cloning repository https://github.com/neverRare/butter
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/neverRare/butter" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FneverRare%2Fbutter", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FneverRare%2Fbutter'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] bf6f81568da2aea27795f2c6d6ce50995b327f0d
[INFO] checking neverRare/butter against master#836c31742687ba4e2f857b5b698e1e9e6b67619c for pr-81789
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FneverRare%2Fbutter" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/neverRare/butter on toolchain 836c31742687ba4e2f857b5b698e1e9e6b67619c
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/neverRare/butter
[INFO] finished tweaking git repo https://github.com/neverRare/butter
[INFO] tweaked toml for git repo https://github.com/neverRare/butter written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/neverRare/butter already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "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] 3c4fb55aa22e4de236a9f0fdb164691112513e59bb235937879ff5ca804948ac
[INFO] running `Command { std: "docker" "start" "-a" "3c4fb55aa22e4de236a9f0fdb164691112513e59bb235937879ff5ca804948ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3c4fb55aa22e4de236a9f0fdb164691112513e59bb235937879ff5ca804948ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3c4fb55aa22e4de236a9f0fdb164691112513e59bb235937879ff5ca804948ac", kill_on_drop: false }`
[INFO] [stdout] 3c4fb55aa22e4de236a9f0fdb164691112513e59bb235937879ff5ca804948ac
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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=forbid" "-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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "check" "--frozen" "--all" "--all-targets" "--message-format=json", 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] 29923f2317691384cb8dbd71725481afc2a401711f0d50905a53dda835e8fdbc
[INFO] running `Command { std: "docker" "start" "-a" "29923f2317691384cb8dbd71725481afc2a401711f0d50905a53dda835e8fdbc", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]     Checking type-system v0.1.0 (/opt/rustwide/workdir/type-system)
[INFO] [stdout] warning: variant is never constructed: `Num`
[INFO] [stdout]   --> type-system/src/cons.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     Num,
[INFO] [stdout]    |     ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Bool`
[INFO] [stdout]   --> type-system/src/cons.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     Bool,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Array`
[INFO] [stdout]   --> type-system/src/cons.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 |     Array(Box<Type<'a>>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Record`
[INFO] [stdout]   --> type-system/src/cons.rs:13:5
[INFO] [stdout]    |
[INFO] [stdout] 13 |     Record(RecordCons<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Fun`
[INFO] [stdout]   --> type-system/src/cons.rs:14:5
[INFO] [stdout]    |
[INFO] [stdout] 14 |     Fun(FunCons<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Tuple`
[INFO] [stdout]   --> type-system/src/cons.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 15 |     Tuple(Box<[Type<'a>]>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Order`
[INFO] [stdout]   --> type-system/src/cons.rs:25:5
[INFO] [stdout]    |
[INFO] [stdout] 25 |     Order(Box<[&'a str]>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Splat`
[INFO] [stdout]   --> type-system/src/cons.rs:26:5
[INFO] [stdout]    |
[INFO] [stdout] 26 |     Splat(Option<Box<Type<'a>>>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Var`
[INFO] [stdout]   --> type-system/src/lib.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 17 |     Var(Var<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Cons`
[INFO] [stdout]   --> type-system/src/lib.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     Cons(Cons<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Subs`
[INFO] [stdout]   --> type-system/src/lib.rs:25:8
[INFO] [stdout]    |
[INFO] [stdout] 25 | struct Subs<'a>(HashMap<Var<'a>, Type<'a>>);
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `hashmap`
[INFO] [stdout]   --> type-system/src/lib.rs:27:8
[INFO] [stdout]    |
[INFO] [stdout] 27 |     fn hashmap(&self) -> &HashMap<Var<'a>, Type<'a>> {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Env`
[INFO] [stdout]   --> type-system/src/lib.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 32 | struct Env<'a>(HashMap<Var<'a>, Scheme<'a>>);
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `hashmap`
[INFO] [stdout]   --> type-system/src/lib.rs:34:8
[INFO] [stdout]    |
[INFO] [stdout] 34 |     fn hashmap(&self) -> &HashMap<Var<'a>, Scheme<'a>> {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 14 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Num`
[INFO] [stdout]   --> type-system/src/cons.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     Num,
[INFO] [stdout]    |     ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Bool`
[INFO] [stdout]   --> type-system/src/cons.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     Bool,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Array`
[INFO] [stdout]   --> type-system/src/cons.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 |     Array(Box<Type<'a>>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Record`
[INFO] [stdout]   --> type-system/src/cons.rs:13:5
[INFO] [stdout]    |
[INFO] [stdout] 13 |     Record(RecordCons<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Fun`
[INFO] [stdout]   --> type-system/src/cons.rs:14:5
[INFO] [stdout]    |
[INFO] [stdout] 14 |     Fun(FunCons<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Tuple`
[INFO] [stdout]   --> type-system/src/cons.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 15 |     Tuple(Box<[Type<'a>]>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Order`
[INFO] [stdout]   --> type-system/src/cons.rs:25:5
[INFO] [stdout]    |
[INFO] [stdout] 25 |     Order(Box<[&'a str]>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Splat`
[INFO] [stdout]   --> type-system/src/cons.rs:26:5
[INFO] [stdout]    |
[INFO] [stdout] 26 |     Splat(Option<Box<Type<'a>>>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Var`
[INFO] [stdout]   --> type-system/src/lib.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 17 |     Var(Var<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Cons`
[INFO] [stdout]   --> type-system/src/lib.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     Cons(Cons<'a>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Subs`
[INFO] [stdout]   --> type-system/src/lib.rs:25:8
[INFO] [stdout]    |
[INFO] [stdout] 25 | struct Subs<'a>(HashMap<Var<'a>, Type<'a>>);
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `hashmap`
[INFO] [stdout]   --> type-system/src/lib.rs:27:8
[INFO] [stdout]    |
[INFO] [stdout] 27 |     fn hashmap(&self) -> &HashMap<Var<'a>, Type<'a>> {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Env`
[INFO] [stdout]   --> type-system/src/lib.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 32 | struct Env<'a>(HashMap<Var<'a>, Scheme<'a>>);
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `hashmap`
[INFO] [stdout]   --> type-system/src/lib.rs:34:8
[INFO] [stdout]    |
[INFO] [stdout] 34 |     fn hashmap(&self) -> &HashMap<Var<'a>, Scheme<'a>> {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 14 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking combine v4.5.2
[INFO] [stderr]     Checking parser v0.1.0 (/opt/rustwide/workdir/parser)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 13.94s
[INFO] running `Command { std: "docker" "inspect" "29923f2317691384cb8dbd71725481afc2a401711f0d50905a53dda835e8fdbc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "29923f2317691384cb8dbd71725481afc2a401711f0d50905a53dda835e8fdbc", kill_on_drop: false }`
[INFO] [stdout] 29923f2317691384cb8dbd71725481afc2a401711f0d50905a53dda835e8fdbc