[INFO] cloning repository https://github.com/imkiwa/RustPlayground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/imkiwa/RustPlayground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fimkiwa%2FRustPlayground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fimkiwa%2FRustPlayground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1d53a9f08260f430c69456b0df2556c59abdb62d
[INFO] testing imkiwa/RustPlayground against beta-2021-08-01 for beta-1.55-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fimkiwa%2FRustPlayground" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/imkiwa/RustPlayground on toolchain beta-2021-08-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/imkiwa/RustPlayground
[INFO] finished tweaking git repo https://github.com/imkiwa/RustPlayground
[INFO] tweaked toml for git repo https://github.com/imkiwa/RustPlayground written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/imkiwa/RustPlayground already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-08-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 03f3e3596abcf50b2c9532f6802e633a690315a7b5c10b5e8a8f532c5bcc6fd6
[INFO] running `Command { std: "docker" "start" "-a" "03f3e3596abcf50b2c9532f6802e633a690315a7b5c10b5e8a8f532c5bcc6fd6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "03f3e3596abcf50b2c9532f6802e633a690315a7b5c10b5e8a8f532c5bcc6fd6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "03f3e3596abcf50b2c9532f6802e633a690315a7b5c10b5e8a8f532c5bcc6fd6", kill_on_drop: false }`
[INFO] [stdout] 03f3e3596abcf50b2c9532f6802e633a690315a7b5c10b5e8a8f532c5bcc6fd6
[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=warn" "-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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-08-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ef57f2a0fd0c20fbf5838a945bba5434c6e55f23b1955852209bddb5f788a04b
[INFO] running `Command { std: "docker" "start" "-a" "ef57f2a0fd0c20fbf5838a945bba5434c6e55f23b1955852209bddb5f788a04b", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling rust_playground v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0308]: mismatched types
[INFO] [stdout]   --> src/playground/calculator.rs:65:32
[INFO] [stdout]    |
[INFO] [stdout] 65 |     fn build_ast(&mut self) -> Box<dyn AST> {
[INFO] [stdout]    |        ---------               ^^^^^^^^^^^^ expected struct `Box`, found `()`
[INFO] [stdout]    |        |
[INFO] [stdout]    |        implicitly returns `()` as its body has no tail or `return` expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: expected struct `Box<(dyn AST + 'static)>`
[INFO] [stdout]            found unit type `()`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0308`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust_playground` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "ef57f2a0fd0c20fbf5838a945bba5434c6e55f23b1955852209bddb5f788a04b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ef57f2a0fd0c20fbf5838a945bba5434c6e55f23b1955852209bddb5f788a04b", kill_on_drop: false }`
[INFO] [stdout] ef57f2a0fd0c20fbf5838a945bba5434c6e55f23b1955852209bddb5f788a04b
