[INFO] fetching crate float_fast_print 0.1.2...
[INFO] checking float_fast_print-0.1.2 against master#836c31742687ba4e2f857b5b698e1e9e6b67619c for pr-81789
[INFO] extracting crate float_fast_print 0.1.2 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate float_fast_print 0.1.2 on toolchain 836c31742687ba4e2f857b5b698e1e9e6b67619c
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate float_fast_print 0.1.2
[INFO] finished tweaking crates.io crate float_fast_print 0.1.2
[INFO] tweaked toml for crates.io crate float_fast_print 0.1.2 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 89727441c18760eb0b39c540022928b50c7933195b44c06fe587639e7cb46417
[INFO] running `Command { std: "docker" "start" "-a" "89727441c18760eb0b39c540022928b50c7933195b44c06fe587639e7cb46417", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "89727441c18760eb0b39c540022928b50c7933195b44c06fe587639e7cb46417", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "89727441c18760eb0b39c540022928b50c7933195b44c06fe587639e7cb46417", kill_on_drop: false }`
[INFO] [stdout] 89727441c18760eb0b39c540022928b50c7933195b44c06fe587639e7cb46417
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ade14e12cf873e5b870c08ad725a22e1bb35b75ccdb89b7d7e973244241d0fe4
[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" "ade14e12cf873e5b870c08ad725a22e1bb35b75ccdb89b7d7e973244241d0fe4", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.93
[INFO] [stderr]     Checking float_fast_print v0.1.2 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> tests/benchmarks.rs:17:9
[INFO] [stdout]    |
[INFO] [stdout] 17 |         write!(&mut buffer, "{:?}", x);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> tests/benchmarks.rs:28:9
[INFO] [stdout]    |
[INFO] [stdout] 28 |         write!(&mut buffer, "{}", x);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> tests/benchmarks.rs:39:9
[INFO] [stdout]    |
[INFO] [stdout] 39 |         write!(&mut buffer, "{:?}", x);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> tests/benchmarks.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |         write!(&mut buffer, "{}", x);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 5.10s
[INFO] running `Command { std: "docker" "inspect" "ade14e12cf873e5b870c08ad725a22e1bb35b75ccdb89b7d7e973244241d0fe4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ade14e12cf873e5b870c08ad725a22e1bb35b75ccdb89b7d7e973244241d0fe4", kill_on_drop: false }`
[INFO] [stdout] ade14e12cf873e5b870c08ad725a22e1bb35b75ccdb89b7d7e973244241d0fe4