[INFO] fetching crate lmarkov 0.1.0...
[INFO] testing lmarkov-0.1.0 against master#350d0ef0ec0493e6d21cfb265cb8211a0e74d766 for pr-145330-1
[INFO] extracting crate lmarkov 0.1.0 into /workspace/builds/worker-4-tc1/source
[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-4-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate lmarkov 0.1.0 on toolchain 350d0ef0ec0493e6d21cfb265cb8211a0e74d766
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+350d0ef0ec0493e6d21cfb265cb8211a0e74d766" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+350d0ef0ec0493e6d21cfb265cb8211a0e74d766" "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: v0.9.2)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+350d0ef0ec0493e6d21cfb265cb8211a0e74d766" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+350d0ef0ec0493e6d21cfb265cb8211a0e74d766" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 418cd62c51e1d751a98500b504069efdbeb22d6c427a104d87a45b6789d643ff
[INFO] running `Command { std: "docker" "start" "-a" "418cd62c51e1d751a98500b504069efdbeb22d6c427a104d87a45b6789d643ff", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "418cd62c51e1d751a98500b504069efdbeb22d6c427a104d87a45b6789d643ff", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "418cd62c51e1d751a98500b504069efdbeb22d6c427a104d87a45b6789d643ff", kill_on_drop: false }`
[INFO] [stdout] 418cd62c51e1d751a98500b504069efdbeb22d6c427a104d87a45b6789d643ff
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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=forbid" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+350d0ef0ec0493e6d21cfb265cb8211a0e74d766" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] edcdef7011b96bd45624c9f0607eb5b687910bdb73ebbc4bfe706d922e3170f9
[INFO] running `Command { std: "docker" "start" "-a" "edcdef7011b96bd45624c9f0607eb5b687910bdb73ebbc4bfe706d922e3170f9", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.176
[INFO] [stderr]    Compiling zerocopy v0.8.27
[INFO] [stderr]    Compiling getrandom v0.1.16
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling ppv-lite86 v0.2.21
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling lmarkov v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 6.33s
[INFO] running `Command { std: "docker" "inspect" "edcdef7011b96bd45624c9f0607eb5b687910bdb73ebbc4bfe706d922e3170f9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "edcdef7011b96bd45624c9f0607eb5b687910bdb73ebbc4bfe706d922e3170f9", kill_on_drop: false }`
[INFO] [stdout] edcdef7011b96bd45624c9f0607eb5b687910bdb73ebbc4bfe706d922e3170f9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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=forbid" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+350d0ef0ec0493e6d21cfb265cb8211a0e74d766" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 61fc3c031eddd394576e626b7f4a77a037f4dff044b3563cde0d9fb71d4b6507
[INFO] running `Command { std: "docker" "start" "-a" "61fc3c031eddd394576e626b7f4a77a037f4dff044b3563cde0d9fb71d4b6507", kill_on_drop: false }`
[INFO] [stderr]    Compiling 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]    |               required by this formatting parameter
[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] [stderr] error: could not compile `lmarkov` (lib test) due to 1 previous error
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "61fc3c031eddd394576e626b7f4a77a037f4dff044b3563cde0d9fb71d4b6507", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "61fc3c031eddd394576e626b7f4a77a037f4dff044b3563cde0d9fb71d4b6507", kill_on_drop: false }`
[INFO] [stdout] 61fc3c031eddd394576e626b7f4a77a037f4dff044b3563cde0d9fb71d4b6507