[INFO] fetching crate float_fast_print 0.1.2...
[INFO] checking float_fast_print-0.1.2 against master#31ee872db5aae4750e3da1ca4ed1523c4356947f for pr-78461
[INFO] extracting crate float_fast_print 0.1.2 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate float_fast_print 0.1.2 on toolchain 31ee872db5aae4750e3da1ca4ed1523c4356947f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+31ee872db5aae4750e3da1ca4ed1523c4356947f" "read-manifest" "--manifest-path" "Cargo.toml", 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-5/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+31ee872db5aae4750e3da1ca4ed1523c4356947f" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+31ee872db5aae4750e3da1ca4ed1523c4356947f" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+31ee872db5aae4750e3da1ca4ed1523c4356947f" "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] 39b64347b7e1a73885038604ccde48b64ab3eada59da863a7aa4f3163602da93
[INFO] running `Command { std: "docker" "start" "-a" "39b64347b7e1a73885038604ccde48b64ab3eada59da863a7aa4f3163602da93", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "39b64347b7e1a73885038604ccde48b64ab3eada59da863a7aa4f3163602da93", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "39b64347b7e1a73885038604ccde48b64ab3eada59da863a7aa4f3163602da93", kill_on_drop: false }`
[INFO] [stdout] 39b64347b7e1a73885038604ccde48b64ab3eada59da863a7aa4f3163602da93
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+31ee872db5aae4750e3da1ca4ed1523c4356947f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 779bb5313854160da695b19c10162fa1c2156e8a70ef373e5804a639b7d87422
[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" "779bb5313854160da695b19c10162fa1c2156e8a70ef373e5804a639b7d87422", kill_on_drop: false }`
[INFO] [stderr]     Checking rand_core v0.4.2
[INFO] [stderr]     Checking float_fast_print v0.1.2 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stdout] warning: unused `std::result::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 `std::result::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 `std::result::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 `std::result::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 3.14s
[INFO] running `Command { std: "docker" "inspect" "779bb5313854160da695b19c10162fa1c2156e8a70ef373e5804a639b7d87422", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "779bb5313854160da695b19c10162fa1c2156e8a70ef373e5804a639b7d87422", kill_on_drop: false }`
[INFO] [stdout] 779bb5313854160da695b19c10162fa1c2156e8a70ef373e5804a639b7d87422