[INFO] cloning repository https://github.com/pierd/exploring-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/pierd/exploring-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpierd%2Fexploring-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpierd%2Fexploring-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b914faaa97ee1b3eb5e1aa14c26fb416cdbfad4f
[INFO] checking pierd/exploring-rust against try#5ec4d3b0c83717313176eefa7d71e9d36dc83355 for 155501-infallible-never-with-reservation
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpierd%2Fexploring-rust" "/workspace/builds/worker-7-tc1/source", kill_on_drop: false }`
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[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/pierd/exploring-rust
[INFO] finished tweaking git repo https://github.com/pierd/exploring-rust
[INFO] tweaked toml for git repo https://github.com/pierd/exploring-rust written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/pierd/exploring-rust on toolchain 5ec4d3b0c83717313176eefa7d71e9d36dc83355
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+5ec4d3b0c83717313176eefa7d71e9d36dc83355" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/pierd/exploring-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+5ec4d3b0c83717313176eefa7d71e9d36dc83355" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
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[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+5ec4d3b0c83717313176eefa7d71e9d36dc83355" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
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[INFO] [stdout] warning: unused import: `Weak`
[INFO] [stdout]  --> src/bin/leaked_weak.rs:1:19
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::rc::{Rc, Weak};
[INFO] [stdout]   |                   ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Semigroup` is never used
[INFO] [stdout]  --> src/bin/monoid.rs:3:7
[INFO] [stdout]   |
[INFO] [stdout] 3 | trait Semigroup {
[INFO] [stdout]   |       ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Monoid` is never used
[INFO] [stdout]  --> src/bin/monoid.rs:8:7
[INFO] [stdout]   |
[INFO] [stdout] 8 | trait Monoid: Semigroup {
[INFO] [stdout]   |       ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Add` is never constructed
[INFO] [stdout]   --> src/bin/monoid.rs:30:8
[INFO] [stdout]    |
[INFO] [stdout] 30 | struct Add;
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Mul` is never constructed
[INFO] [stdout]   --> src/bin/monoid.rs:45:8
[INFO] [stdout]    |
[INFO] [stdout] 45 | struct Mul;
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Max` is never constructed
[INFO] [stdout]   --> src/bin/monoid.rs:60:8
[INFO] [stdout]    |
[INFO] [stdout] 60 | struct Max;
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `VecAppend` is never constructed
[INFO] [stdout]   --> src/bin/monoid.rs:75:8
[INFO] [stdout]    |
[INFO] [stdout] 75 | struct VecAppend<T>(std::marker::PhantomData<T>);
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `StringAppend` is never constructed
[INFO] [stdout]   --> src/bin/monoid.rs:90:8
[INFO] [stdout]    |
[INFO] [stdout] 90 | struct StringAppend;
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `Fun` is never used
[INFO] [stdout]    --> src/bin/monoid.rs:177:6
[INFO] [stdout]     |
[INFO] [stdout] 177 | type Fun<Args, Return> = Rc<dyn Fn(Args) -> Return>;
[INFO] [stdout]     |      ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `TraverseFn` is never constructed
[INFO] [stdout]    --> src/bin/monoid.rs:179:8
[INFO] [stdout]     |
[INFO] [stdout] 179 | struct TraverseFn<A, B>(std::marker::PhantomData<(A, B)>);
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `Endomorphism` is never used
[INFO] [stdout]    --> src/bin/monoid.rs:203:6
[INFO] [stdout]     |
[INFO] [stdout] 203 | type Endomorphism<A> = Fun<A, A>;
[INFO] [stdout]     |      ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `ComposeEndomorphism` is never constructed
[INFO] [stdout]    --> src/bin/monoid.rs:205:8
[INFO] [stdout]     |
[INFO] [stdout] 205 | struct ComposeEndomorphism<A>(std::marker::PhantomData<A>);
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated functions `times` and `accumulate` are never used
[INFO] [stdout]   --> src/bin/monoid.rs:11:8
[INFO] [stdout]    |
[INFO] [stdout]  8 | trait Monoid: Semigroup {
[INFO] [stdout]    |       ------ associated functions in this trait
[INFO] [stdout] ...
[INFO] [stdout] 11 |     fn times(a: Self::T, n: usize) -> Self::T
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 22 |     fn accumulate<I>(iter: I) -> Self::T
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Weak`
[INFO] [stdout]  --> src/bin/leaked_weak.rs:1:19
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::rc::{Rc, Weak};
[INFO] [stdout]   |                   ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 37.88s
[INFO] running `Command { std: "docker" "inspect" "9a95a8e730c5c4952fb4f059733708788584f20977ff204fe0424dc3aa2f9693", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9a95a8e730c5c4952fb4f059733708788584f20977ff204fe0424dc3aa2f9693", kill_on_drop: false }`
[INFO] [stdout] 9a95a8e730c5c4952fb4f059733708788584f20977ff204fe0424dc3aa2f9693