[INFO] fetching crate lmarkov 0.1.0...
[INFO] checking lmarkov-0.1.0 against master#ff1737bb00913444173658b4e0b274fd79aabf66 for pr-132712-1
[INFO] extracting crate lmarkov 0.1.0 into /workspace/builds/worker-7-tc1/source
[INFO] validating manifest of crates.io crate lmarkov 0.1.0 on toolchain ff1737bb00913444173658b4e0b274fd79aabf66
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ff1737bb00913444173658b4e0b274fd79aabf66" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate lmarkov 0.1.0
[INFO] finished tweaking crates.io crate lmarkov 0.1.0
[INFO] tweaked toml for crates.io crate lmarkov 0.1.0 written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ff1737bb00913444173658b4e0b274fd79aabf66" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 22 packages to latest compatible versions
[INFO] [stderr]       Adding rand v0.7.3 (available: v0.8.5)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ff1737bb00913444173658b4e0b274fd79aabf66" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:4a844ea9eb2546a2d2c7022eacef16ef2e8229c7fbb2c7d4d55a9ceca922f72d" "/opt/rustwide/cargo-home/bin/cargo" "+ff1737bb00913444173658b4e0b274fd79aabf66" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c8a687a7841c82027648643719f4e59734dc13e6566004478bd60940261cda4a
[INFO] running `Command { std: "docker" "start" "-a" "c8a687a7841c82027648643719f4e59734dc13e6566004478bd60940261cda4a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c8a687a7841c82027648643719f4e59734dc13e6566004478bd60940261cda4a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c8a687a7841c82027648643719f4e59734dc13e6566004478bd60940261cda4a", kill_on_drop: false }`
[INFO] [stdout] c8a687a7841c82027648643719f4e59734dc13e6566004478bd60940261cda4a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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=allow" "-e" "RUSTDOCFLAGS=--cap-lints=allow" "-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@sha256:4a844ea9eb2546a2d2c7022eacef16ef2e8229c7fbb2c7d4d55a9ceca922f72d" "/opt/rustwide/cargo-home/bin/cargo" "+ff1737bb00913444173658b4e0b274fd79aabf66" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a7f4738d79aae2d14d3238e4663e9e57ff270facbe9456b68fa04a2ab747dd99
[INFO] running `Command { std: "docker" "start" "-a" "a7f4738d79aae2d14d3238e4663e9e57ff270facbe9456b68fa04a2ab747dd99", kill_on_drop: false }`
[INFO] [stderr]     Checking getrandom v0.1.16
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking lmarkov v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0277]: `Option<String>` doesn't implement `std::fmt::Display`
[INFO] [stdout]   --> src/tests.rs:10:20
[INFO] [stdout]    |
[INFO] [stdout] 10 |     println!("{}", chain.generate());
[INFO] [stdout]    |                    ^^^^^^^^^^^^^^^^ `Option<String>` cannot be formatted with the default formatter
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `std::fmt::Display` is not implemented for `Option<String>`
[INFO] [stdout]    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
[INFO] [stdout]    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `lmarkov` (lib test) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "a7f4738d79aae2d14d3238e4663e9e57ff270facbe9456b68fa04a2ab747dd99", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a7f4738d79aae2d14d3238e4663e9e57ff270facbe9456b68fa04a2ab747dd99", kill_on_drop: false }`
[INFO] [stdout] a7f4738d79aae2d14d3238e4663e9e57ff270facbe9456b68fa04a2ab747dd99