[INFO] cloning repository https://github.com/jrmoulton/rust_interview_questions
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/jrmoulton/rust_interview_questions" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjrmoulton%2Frust_interview_questions", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjrmoulton%2Frust_interview_questions'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3b4e189dbab14403930d9416fba3c5a01baf51ae
[INFO] checking jrmoulton/rust_interview_questions against master#9748d87dc70a9a6725c5dbd76ce29d04752b4f90 for pr-144156
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjrmoulton%2Frust_interview_questions" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/jrmoulton/rust_interview_questions
[INFO] finished tweaking git repo https://github.com/jrmoulton/rust_interview_questions
[INFO] tweaked toml for git repo https://github.com/jrmoulton/rust_interview_questions written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/jrmoulton/rust_interview_questions on toolchain 9748d87dc70a9a6725c5dbd76ce29d04752b4f90
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9748d87dc70a9a6725c5dbd76ce29d04752b4f90" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/jrmoulton/rust_interview_questions 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" "+9748d87dc70a9a6725c5dbd76ce29d04752b4f90" "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-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+9748d87dc70a9a6725c5dbd76ce29d04752b4f90" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e36c06740407f9a30eaf6f23da366bd56bc62a93ea184e3c42004978752b4d2b
[INFO] running `Command { std: "docker" "start" "-a" "e36c06740407f9a30eaf6f23da366bd56bc62a93ea184e3c42004978752b4d2b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e36c06740407f9a30eaf6f23da366bd56bc62a93ea184e3c42004978752b4d2b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e36c06740407f9a30eaf6f23da366bd56bc62a93ea184e3c42004978752b4d2b", kill_on_drop: false }`
[INFO] [stdout] e36c06740407f9a30eaf6f23da366bd56bc62a93ea184e3c42004978752b4d2b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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" "-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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+9748d87dc70a9a6725c5dbd76ce29d04752b4f90" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7d29fa9c18238180637b768991933157e4bc76e03337b76dd5653799291a286c
[INFO] running `Command { std: "docker" "start" "-a" "7d29fa9c18238180637b768991933157e4bc76e03337b76dd5653799291a286c", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.67
[INFO] [stderr]    Compiling futures-core v0.3.23
[INFO] [stderr]    Compiling futures-task v0.3.23
[INFO] [stderr]    Compiling futures-channel v0.3.23
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]    Compiling futures-util v0.3.23
[INFO] [stderr]     Checking futures-sink v0.3.23
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]     Checking pin-project-lite v0.2.9
[INFO] [stderr]     Checking futures-io v0.3.23
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling futures-macro v0.3.23
[INFO] [stderr]     Checking futures-executor v0.3.23
[INFO] [stderr]     Checking futures v0.3.23
[INFO] [stderr]     Checking interview_questions v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait `MyString` is never used
[INFO] [stdout]  --> src/divide_ints.rs:1:7
[INFO] [stdout]   |
[INFO] [stdout] 1 | trait MyString {
[INFO] [stdout]   |       ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::slice::Iter` that must be used
[INFO] [stdout]   --> src/long_sum.rs:35:5
[INFO] [stdout]    |
[INFO] [stdout] 35 |     s.iter();
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: iterators are lazy and do nothing unless consumed
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 35 |     let _ = s.iter();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `MyString` is never used
[INFO] [stdout]  --> src/divide_ints.rs:1:7
[INFO] [stdout]   |
[INFO] [stdout] 1 | trait MyString {
[INFO] [stdout]   |       ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::slice::Iter` that must be used
[INFO] [stdout]   --> src/long_sum.rs:35:5
[INFO] [stdout]    |
[INFO] [stdout] 35 |     s.iter();
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: iterators are lazy and do nothing unless consumed
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 35 |     let _ = s.iter();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 9.42s
[INFO] running `Command { std: "docker" "inspect" "7d29fa9c18238180637b768991933157e4bc76e03337b76dd5653799291a286c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7d29fa9c18238180637b768991933157e4bc76e03337b76dd5653799291a286c", kill_on_drop: false }`
[INFO] [stdout] 7d29fa9c18238180637b768991933157e4bc76e03337b76dd5653799291a286c