[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] ce80bde42212e0f9feb06ae4141a1a4dd35fb3ba
[INFO] checking neverRare/butter against master#33fdb797f59421c7bbecaa4588ed5d7a31a9494a for pr-87190-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FneverRare%2Fbutter" "/workspace/builds/worker-72/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-72/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/neverRare/butter on toolchain 33fdb797f59421c7bbecaa4588ed5d7a31a9494a
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "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-72/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" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-72/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-72/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" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f0e3df76f38219531eda1c85d778b04aaff063162799eddeb40f7e7ccffecdb2
[INFO] running `Command { std: "docker" "start" "-a" "f0e3df76f38219531eda1c85d778b04aaff063162799eddeb40f7e7ccffecdb2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f0e3df76f38219531eda1c85d778b04aaff063162799eddeb40f7e7ccffecdb2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f0e3df76f38219531eda1c85d778b04aaff063162799eddeb40f7e7ccffecdb2", kill_on_drop: false }`
[INFO] [stdout] f0e3df76f38219531eda1c85d778b04aaff063162799eddeb40f7e7ccffecdb2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-72/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-72/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2a75c55125752c786b763bb5bc68b1516ae4043d66472b8f92b0b255efb4b956
[INFO] running `Command { std: "docker" "start" "-a" "2a75c55125752c786b763bb5bc68b1516ae4043d66472b8f92b0b255efb4b956", kill_on_drop: false }`
[INFO] [stderr]    Compiling version_check v0.9.3
[INFO] [stderr]    Compiling proc-macro2 v1.0.28
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.75
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling libc v0.2.100
[INFO] [stderr]     Checking hir v0.1.0 (/opt/rustwide/workdir/hir)
[INFO] [stderr]    Compiling unicode-segmentation v1.8.0
[INFO] [stderr]     Checking unicode-width v0.1.8
[INFO] [stderr]     Checking bytes v1.0.1
[INFO] [stderr]     Checking strsim v0.8.0
[INFO] [stderr]     Checking vec_map v0.8.2
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking bitflags v1.3.2
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking type-system v0.1.0 (/opt/rustwide/workdir/type-system)
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stdout] warning: unused variable: `statements`
[INFO] [stdout]    --> type-system/src/lib.rs:152:14
[INFO] [stdout]     |
[INFO] [stdout] 152 | pub fn infer(statements: Vec<Statement<()>>) -> Result<Vec<Statement<Type>>, TypeError> {
[INFO] [stdout]     |              ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_statements`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `statements`
[INFO] [stdout]    --> type-system/src/lib.rs:152:14
[INFO] [stdout]     |
[INFO] [stdout] 152 | pub fn infer(statements: Vec<Statement<()>>) -> Result<Vec<Statement<Type>>, TypeError> {
[INFO] [stdout]     |              ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_statements`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `kind`
[INFO] [stdout]    --> type-system/src/ty.rs:164:8
[INFO] [stdout]     |
[INFO] [stdout] 164 |     fn kind(&self) -> Kind {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `free_vars`
[INFO] [stdout]    --> type-system/src/ty.rs:170:8
[INFO] [stdout]     |
[INFO] [stdout] 170 |     fn free_vars(&self) -> HashSet<KindedVar<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `free_vars`
[INFO] [stdout]    --> type-system/src/ty.rs:189:8
[INFO] [stdout]     |
[INFO] [stdout] 189 |     fn free_vars(&self) -> HashSet<KindedVar<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `substitute`
[INFO] [stdout]    --> type-system/src/ty.rs:196:8
[INFO] [stdout]     |
[INFO] [stdout] 196 |     fn substitute(&mut self, subs: &Subs<'a>) -> Result<(), TypeError> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `filter_off`
[INFO] [stdout]    --> type-system/src/ty.rs:246:8
[INFO] [stdout]     |
[INFO] [stdout] 246 |     fn filter_off(&mut self, vars: &HashSet<KindedVar<'a>>) {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `hashmap_mut`
[INFO] [stdout]    --> type-system/src/ty.rs:278:8
[INFO] [stdout]     |
[INFO] [stdout] 278 |     fn hashmap_mut(&mut self) -> &mut HashMap<Var<'a>, Scheme<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `remove`
[INFO] [stdout]    --> type-system/src/ty.rs:285:8
[INFO] [stdout]     |
[INFO] [stdout] 285 |     fn remove(&mut self, var: Var<'a>) {
[INFO] [stdout]     |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `free_vars`
[INFO] [stdout]    --> type-system/src/ty.rs:288:8
[INFO] [stdout]     |
[INFO] [stdout] 288 |     fn free_vars(&self) -> HashSet<KindedVar<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `substitute`
[INFO] [stdout]    --> type-system/src/ty.rs:294:8
[INFO] [stdout]     |
[INFO] [stdout] 294 |     fn substitute(&mut self, subs: &Subs<'a>) -> Result<(), TypeError> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `generalize`
[INFO] [stdout]    --> type-system/src/ty.rs:300:8
[INFO] [stdout]     |
[INFO] [stdout] 300 |     fn generalize(&self, ty: Type<'a>) -> Scheme<'a> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `kind`
[INFO] [stdout]    --> type-system/src/ty.rs:164:8
[INFO] [stdout]     |
[INFO] [stdout] 164 |     fn kind(&self) -> Kind {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `free_vars`
[INFO] [stdout]    --> type-system/src/ty.rs:170:8
[INFO] [stdout]     |
[INFO] [stdout] 170 |     fn free_vars(&self) -> HashSet<KindedVar<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `free_vars`
[INFO] [stdout]    --> type-system/src/ty.rs:189:8
[INFO] [stdout]     |
[INFO] [stdout] 189 |     fn free_vars(&self) -> HashSet<KindedVar<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `substitute`
[INFO] [stdout]    --> type-system/src/ty.rs:196:8
[INFO] [stdout]     |
[INFO] [stdout] 196 |     fn substitute(&mut self, subs: &Subs<'a>) -> Result<(), TypeError> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `filter_off`
[INFO] [stdout]    --> type-system/src/ty.rs:246:8
[INFO] [stdout]     |
[INFO] [stdout] 246 |     fn filter_off(&mut self, vars: &HashSet<KindedVar<'a>>) {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `hashmap_mut`
[INFO] [stdout]    --> type-system/src/ty.rs:278:8
[INFO] [stdout]     |
[INFO] [stdout] 278 |     fn hashmap_mut(&mut self) -> &mut HashMap<Var<'a>, Scheme<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `remove`
[INFO] [stdout]    --> type-system/src/ty.rs:285:8
[INFO] [stdout]     |
[INFO] [stdout] 285 |     fn remove(&mut self, var: Var<'a>) {
[INFO] [stdout]     |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `free_vars`
[INFO] [stdout]    --> type-system/src/ty.rs:288:8
[INFO] [stdout]     |
[INFO] [stdout] 288 |     fn free_vars(&self) -> HashSet<KindedVar<'a>> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `substitute`
[INFO] [stdout]    --> type-system/src/ty.rs:294:8
[INFO] [stdout]     |
[INFO] [stdout] 294 |     fn substitute(&mut self, subs: &Subs<'a>) -> Result<(), TypeError> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `generalize`
[INFO] [stdout]    --> type-system/src/ty.rs:300:8
[INFO] [stdout]     |
[INFO] [stdout] 300 |     fn generalize(&self, ty: Type<'a>) -> Scheme<'a> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]     Checking combine v4.6.0
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]     Checking parser v0.1.0 (/opt/rustwide/workdir/parser)
[INFO] [stderr]    Compiling structopt-derive v0.4.15
[INFO] [stderr]     Checking structopt v0.3.22
[INFO] [stderr]     Checking butter v0.1.0 (/opt/rustwide/workdir/cli)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 17.22s
[INFO] running `Command { std: "docker" "inspect" "2a75c55125752c786b763bb5bc68b1516ae4043d66472b8f92b0b255efb4b956", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2a75c55125752c786b763bb5bc68b1516ae4043d66472b8f92b0b255efb4b956", kill_on_drop: false }`
[INFO] [stdout] 2a75c55125752c786b763bb5bc68b1516ae4043d66472b8f92b0b255efb4b956