[INFO] cloning repository https://github.com/0xksure/rust-interview-prep
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/0xksure/rust-interview-prep" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2F0xksure%2Frust-interview-prep", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2F0xksure%2Frust-interview-prep'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ef2bc53a1fac1ddd19d380413da1b075ca9e3573
[INFO] building 0xksure/rust-interview-prep against master#11663cd3bfefef7d34e8f0892c250bf698049392+rustflags=-Dtail-expr-drop-order for pr-134523
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2F0xksure%2Frust-interview-prep" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/0xksure/rust-interview-prep on toolchain 11663cd3bfefef7d34e8f0892c250bf698049392
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/0xksure/rust-interview-prep
[INFO] finished tweaking git repo https://github.com/0xksure/rust-interview-prep
[INFO] tweaked toml for git repo https://github.com/0xksure/rust-interview-prep written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/0xksure/rust-interview-prep 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" "+11663cd3bfefef7d34e8f0892c250bf698049392" "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 getrandom v0.2.6
[INFO] [stderr]   Downloaded libc v0.2.125
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 701f12b8b768b0e8d9a68b1699ef58f5549938e47020f84e6a0d181e1dcd66b3
[INFO] running `Command { std: "docker" "start" "-a" "701f12b8b768b0e8d9a68b1699ef58f5549938e47020f84e6a0d181e1dcd66b3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "701f12b8b768b0e8d9a68b1699ef58f5549938e47020f84e6a0d181e1dcd66b3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "701f12b8b768b0e8d9a68b1699ef58f5549938e47020f84e6a0d181e1dcd66b3", kill_on_drop: false }`
[INFO] [stdout] 701f12b8b768b0e8d9a68b1699ef58f5549938e47020f84e6a0d181e1dcd66b3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid -Dtail-expr-drop-order" "-e" "RUSTDOCFLAGS=--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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e8ce3371f296cc674d0ebd0e69f98c19afac7749dc0705ec4bc2cb4ef132a345
[INFO] running `Command { std: "docker" "start" "-a" "e8ce3371f296cc674d0ebd0e69f98c19afac7749dc0705ec4bc2cb4ef132a345", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.125
[INFO] [stderr]    Compiling getrandom v0.2.6
[INFO] [stderr]    Compiling rand_core v0.6.3
[INFO] [stderr]    Compiling rand_chacha v0.3.1
[INFO] [stderr]    Compiling rand v0.8.5
[INFO] [stderr]    Compiling rust-interview-prep v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `rand::prelude::*`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use rand::prelude::*;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ops::BitXor`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::ops::BitXor;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `fmt::format` and `hash::Hash`
[INFO] [stdout]  --> src/algorithms/mod.rs:1:11
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::{fmt::format, hash::Hash};
[INFO] [stdout]   |           ^^^^^^^^^^^  ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cell::Ref`
[INFO] [stdout]  --> src/lifetimes.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cell::Ref;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_string`
[INFO] [stdout]   --> src/lifetimes.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let new_string = longest(&string1, &string2);
[INFO] [stdout]    |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_string`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_struct`
[INFO] [stdout]   --> src/lifetimes.rs:28:13
[INFO] [stdout]    |
[INFO] [stdout] 28 |         let reference_struct = ReferenceStruct {
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_reference_struct`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_box`
[INFO] [stdout]  --> src/smart_pointers.rs:2:9
[INFO] [stdout]   |
[INFO] [stdout] 2 |     let some_box = Box::new(5);
[INFO] [stdout]   |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_box`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `hash` is never read
[INFO] [stdout]  --> src/algorithms/mod.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | pub struct HashItem<U, T> {
[INFO] [stdout]   |            -------- field in this struct
[INFO] [stdout] 8 |     hash: U,
[INFO] [stdout]   |     ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `string1` is never read
[INFO] [stdout]  --> src/lifetimes.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct ReferenceStruct<'a> {
[INFO] [stdout]   |        --------------- field in this struct
[INFO] [stdout] 4 |     pub string1: &'a str,
[INFO] [stdout]   |         ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.13s
[INFO] running `Command { std: "docker" "inspect" "e8ce3371f296cc674d0ebd0e69f98c19afac7749dc0705ec4bc2cb4ef132a345", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e8ce3371f296cc674d0ebd0e69f98c19afac7749dc0705ec4bc2cb4ef132a345", kill_on_drop: false }`
[INFO] [stdout] e8ce3371f296cc674d0ebd0e69f98c19afac7749dc0705ec4bc2cb4ef132a345
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid -Dtail-expr-drop-order" "-e" "RUSTDOCFLAGS=--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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] cc21f29c3375eca761fa71bc7ca551daece9b1f25eddbc6ab3b92364d71d9973
[INFO] running `Command { std: "docker" "start" "-a" "cc21f29c3375eca761fa71bc7ca551daece9b1f25eddbc6ab3b92364d71d9973", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust-interview-prep v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `rand::prelude::*`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use rand::prelude::*;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ops::BitXor`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::ops::BitXor;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `fmt::format` and `hash::Hash`
[INFO] [stdout]  --> src/algorithms/mod.rs:1:11
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::{fmt::format, hash::Hash};
[INFO] [stdout]   |           ^^^^^^^^^^^  ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cell::Ref`
[INFO] [stdout]  --> src/lifetimes.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cell::Ref;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_string`
[INFO] [stdout]   --> src/lifetimes.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let new_string = longest(&string1, &string2);
[INFO] [stdout]    |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_string`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_struct`
[INFO] [stdout]   --> src/lifetimes.rs:28:13
[INFO] [stdout]    |
[INFO] [stdout] 28 |         let reference_struct = ReferenceStruct {
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_reference_struct`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_box`
[INFO] [stdout]  --> src/smart_pointers.rs:2:9
[INFO] [stdout]   |
[INFO] [stdout] 2 |     let some_box = Box::new(5);
[INFO] [stdout]   |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_box`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `hash` is never read
[INFO] [stdout]  --> src/algorithms/mod.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | pub struct HashItem<U, T> {
[INFO] [stdout]   |            -------- field in this struct
[INFO] [stdout] 8 |     hash: U,
[INFO] [stdout]   |     ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `string1` is never read
[INFO] [stdout]  --> src/lifetimes.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct ReferenceStruct<'a> {
[INFO] [stdout]   |        --------------- field in this struct
[INFO] [stdout] 4 |     pub string1: &'a str,
[INFO] [stdout]   |         ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.26s
[INFO] running `Command { std: "docker" "inspect" "cc21f29c3375eca761fa71bc7ca551daece9b1f25eddbc6ab3b92364d71d9973", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cc21f29c3375eca761fa71bc7ca551daece9b1f25eddbc6ab3b92364d71d9973", kill_on_drop: false }`
[INFO] [stdout] cc21f29c3375eca761fa71bc7ca551daece9b1f25eddbc6ab3b92364d71d9973