[INFO] cloning repository https://github.com/james-mchugh/rust_serde_json_testing
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/james-mchugh/rust_serde_json_testing" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjames-mchugh%2Frust_serde_json_testing", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjames-mchugh%2Frust_serde_json_testing'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 195be4beab40b7c83206afef6049b3e5e21c010a
[INFO] checking james-mchugh/rust_serde_json_testing against try#4f260f0f20b3133d20cfb50353c0221943af5796+rustflags=-Dunmustuse_in_always_ok for pr-148577
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjames-mchugh%2Frust_serde_json_testing" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/james-mchugh/rust_serde_json_testing
[INFO] finished tweaking git repo https://github.com/james-mchugh/rust_serde_json_testing
[INFO] tweaked toml for git repo https://github.com/james-mchugh/rust_serde_json_testing written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/james-mchugh/rust_serde_json_testing on toolchain 4f260f0f20b3133d20cfb50353c0221943af5796
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/james-mchugh/rust_serde_json_testing 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" "+4f260f0f20b3133d20cfb50353c0221943af5796" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4ee02a32a040cdb769ceda940bb32f3c1dea236a1150e08b0ea04468c4afae9f
[INFO] running `Command { std: "docker" "start" "-a" "4ee02a32a040cdb769ceda940bb32f3c1dea236a1150e08b0ea04468c4afae9f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4ee02a32a040cdb769ceda940bb32f3c1dea236a1150e08b0ea04468c4afae9f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4ee02a32a040cdb769ceda940bb32f3c1dea236a1150e08b0ea04468c4afae9f", kill_on_drop: false }`
[INFO] [stdout] 4ee02a32a040cdb769ceda940bb32f3c1dea236a1150e08b0ea04468c4afae9f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/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 -Dunmustuse_in_always_ok" "-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6ff822248e0550d6f1b6aac75feff3f313e2e95b0c7679a54d03a8e890f65290
[INFO] running `Command { std: "docker" "start" "-a" "6ff822248e0550d6f1b6aac75feff3f313e2e95b0c7679a54d03a8e890f65290", kill_on_drop: false }`
[INFO] [stderr]    Compiling cc v1.2.9
[INFO] [stderr]    Compiling serde v1.0.217
[INFO] [stderr]    Compiling serde_json v1.0.135
[INFO] [stderr]    Compiling libc v0.2.169
[INFO] [stderr]    Compiling jemalloc-sys v0.3.2
[INFO] [stderr]     Checking jemallocator v0.3.2
[INFO] [stderr]     Checking json_test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `serde::Deserialize`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use serde::Deserialize;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashMap`
[INFO] [stdout]  --> src/main.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::collections::HashMap;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::env`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::env;
[INFO] [stdout]   |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::error::Error`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::error::Error;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fs::File`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::fs::File;
[INFO] [stdout]   |     ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::Read`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::io::Read;
[INFO] [stdout]   |     ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::path::Path`
[INFO] [stdout]  --> src/main.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 | use std::path::Path;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `serde::Deserialize`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use serde::Deserialize;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashMap`
[INFO] [stdout]  --> src/main.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::collections::HashMap;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::env`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::env;
[INFO] [stdout]   |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::error::Error`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::error::Error;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fs::File`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::fs::File;
[INFO] [stdout]   |     ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::Read`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::io::Read;
[INFO] [stdout]   |     ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::path::Path`
[INFO] [stdout]  --> src/main.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 | use std::path::Path;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/main.rs:39:13
[INFO] [stdout]    |
[INFO] [stdout] 39 |         for i in 0..MAX_ITER {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<std::string::String, Infallible>
[INFO] [stdout]   --> src/main.rs:31:20
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let contents = String::from_str("{\"foo\": \"bar\"}").unwrap();
[INFO] [stdout]    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: requested on the command line with `-D unmustuse-in-always-ok`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/main.rs:39:13
[INFO] [stdout]    |
[INFO] [stdout] 39 |         for i in 0..MAX_ITER {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<std::string::String, Infallible>
[INFO] [stdout]   --> src/main.rs:31:20
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let contents = String::from_str("{\"foo\": \"bar\"}").unwrap();
[INFO] [stdout]    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: requested on the command line with `-D unmustuse-in-always-ok`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `json_test` (bin "json_test") due to 1 previous error; 8 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: could not compile `json_test` (bin "json_test" test) due to 1 previous error; 8 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "6ff822248e0550d6f1b6aac75feff3f313e2e95b0c7679a54d03a8e890f65290", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6ff822248e0550d6f1b6aac75feff3f313e2e95b0c7679a54d03a8e890f65290", kill_on_drop: false }`
[INFO] [stdout] 6ff822248e0550d6f1b6aac75feff3f313e2e95b0c7679a54d03a8e890f65290
