[INFO] fetching crate ak-codegen 0.1.1...
[INFO] testing ak-codegen-0.1.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate ak-codegen 0.1.1 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate ak-codegen 0.1.1 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate ak-codegen 0.1.1
[INFO] finished tweaking crates.io crate ak-codegen 0.1.1
[INFO] tweaked toml for crates.io crate ak-codegen 0.1.1 written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c7949b9c0c934fdc7efd5019d3a6926b1f2b2b2f28949e6a0ab1eedf56eba210
[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" "c7949b9c0c934fdc7efd5019d3a6926b1f2b2b2f28949e6a0ab1eedf56eba210", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c7949b9c0c934fdc7efd5019d3a6926b1f2b2b2f28949e6a0ab1eedf56eba210", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c7949b9c0c934fdc7efd5019d3a6926b1f2b2b2f28949e6a0ab1eedf56eba210", kill_on_drop: false }`
[INFO] [stdout] c7949b9c0c934fdc7efd5019d3a6926b1f2b2b2f28949e6a0ab1eedf56eba210
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", 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] c5fb15f0675eaa508916b72086cd87828abea7376e8548e6af589742d749042d
[INFO] running `Command { std: "docker" "start" "-a" "c5fb15f0675eaa508916b72086cd87828abea7376e8548e6af589742d749042d", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling strsim v0.9.3
[INFO] [stderr]    Compiling ident_case v1.0.1
[INFO] [stderr]    Compiling darling_core v0.10.2
[INFO] [stderr]    Compiling darling_macro v0.10.2
[INFO] [stderr]    Compiling darling v0.10.2
[INFO] [stderr]    Compiling ak-codegen v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(box_syntax)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> src/lib.rs:48:9
[INFO] [stdout]    |
[INFO] [stdout] 47 |         panic!("expr : {}", expr.to_token_stream());
[INFO] [stdout]    |         -------------------------------------------- any code following this expression is unreachable
[INFO] [stdout] 48 |         quote!(#expr).into()
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^ unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `ak-codegen`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "c5fb15f0675eaa508916b72086cd87828abea7376e8548e6af589742d749042d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c5fb15f0675eaa508916b72086cd87828abea7376e8548e6af589742d749042d", kill_on_drop: false }`
[INFO] [stdout] c5fb15f0675eaa508916b72086cd87828abea7376e8548e6af589742d749042d