[INFO] fetching crate letterman 0.0.1...
[INFO] checking letterman-0.0.1 against master#0dce3f606e05cffab7361c132a399d3550ab0df8 for pr-78376
[INFO] extracting crate letterman 0.0.1 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate letterman 0.0.1 on toolchain 0dce3f606e05cffab7361c132a399d3550ab0df8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate letterman 0.0.1
[INFO] finished tweaking crates.io crate letterman 0.0.1
[INFO] tweaked toml for crates.io crate letterman 0.0.1 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate crates.io crate letterman 0.0.1 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 10a4fa8797e06a712e2cb4d29d222a4f3c225a4336297344e1a4996377f04d75
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "10a4fa8797e06a712e2cb4d29d222a4f3c225a4336297344e1a4996377f04d75", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "10a4fa8797e06a712e2cb4d29d222a4f3c225a4336297344e1a4996377f04d75", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "10a4fa8797e06a712e2cb4d29d222a4f3c225a4336297344e1a4996377f04d75", kill_on_drop: false }`
[INFO] [stdout] 10a4fa8797e06a712e2cb4d29d222a4f3c225a4336297344e1a4996377f04d75
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4b29d4a29958218167e04be546891a870c2c73ac3416ddd8148b4d5a2342d051
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "4b29d4a29958218167e04be546891a870c2c73ac3416ddd8148b4d5a2342d051", kill_on_drop: false }`
[INFO] [stderr]     Checking base64 v0.11.0
[INFO] [stderr]     Checking letterman v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/io.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let mut line_vec: Vec<&str> = line.split("\r\n").collect::<Vec<&str>>();
[INFO] [stdout]     |         ----^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/io.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let mut line_vec: Vec<&str> = line.split("\r\n").collect::<Vec<&str>>();
[INFO] [stdout]     |         ----^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/io.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let mut line_vec: Vec<&str> = line.split("\r\n").collect::<Vec<&str>>();
[INFO] [stdout]     |         ----^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/io.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let mut line_vec: Vec<&str> = line.split("\r\n").collect::<Vec<&str>>();
[INFO] [stdout]     |         ----^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.50s
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "4b29d4a29958218167e04be546891a870c2c73ac3416ddd8148b4d5a2342d051", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4b29d4a29958218167e04be546891a870c2c73ac3416ddd8148b4d5a2342d051", kill_on_drop: false }`
[INFO] [stdout] 4b29d4a29958218167e04be546891a870c2c73ac3416ddd8148b4d5a2342d051