[INFO] fetching crate try-let 0.2.0...
[INFO] testing try-let-0.2.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate try-let 0.2.0 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate try-let 0.2.0 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 try-let 0.2.0
[INFO] finished tweaking crates.io crate try-let 0.2.0
[INFO] tweaked toml for crates.io crate try-let 0.2.0 written to /workspace/builds/worker-10/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-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4e5cc24e71d71a1b734bd1ce6e1a21327d3d61c902b78299c5f7379710d92e5e
[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" "4e5cc24e71d71a1b734bd1ce6e1a21327d3d61c902b78299c5f7379710d92e5e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4e5cc24e71d71a1b734bd1ce6e1a21327d3d61c902b78299c5f7379710d92e5e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4e5cc24e71d71a1b734bd1ce6e1a21327d3d61c902b78299c5f7379710d92e5e", kill_on_drop: false }`
[INFO] [stdout] 4e5cc24e71d71a1b734bd1ce6e1a21327d3d61c902b78299c5f7379710d92e5e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ea397572f71f2461ab6dabd8cf8a7e13a62a0cf0fb4b8bcc155c8c456658a09a
[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" "ea397572f71f2461ab6dabd8cf8a7e13a62a0cf0fb4b8bcc155c8c456658a09a", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling try-let v0.2.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 10.06s
[INFO] running `Command { std: "docker" "inspect" "ea397572f71f2461ab6dabd8cf8a7e13a62a0cf0fb4b8bcc155c8c456658a09a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ea397572f71f2461ab6dabd8cf8a7e13a62a0cf0fb4b8bcc155c8c456658a09a", kill_on_drop: false }`
[INFO] [stdout] ea397572f71f2461ab6dabd8cf8a7e13a62a0cf0fb4b8bcc155c8c456658a09a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen" "--no-run" "--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] 8e39d3ecf799dfba68eabb8936223ff57adbf06830fe4280c21d268b76c8440b
[INFO] running `Command { std: "docker" "start" "-a" "8e39d3ecf799dfba68eabb8936223ff57adbf06830fe4280c21d268b76c8440b", kill_on_drop: false }`
[INFO] [stderr]    Compiling try-let v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> tests/bindings_after_at.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(proc_macro_hygiene)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> tests/bindings_after_at.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(bindings_after_at)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `try-let`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> tests/basic_use.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(proc_macro_hygiene)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[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 E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "8e39d3ecf799dfba68eabb8936223ff57adbf06830fe4280c21d268b76c8440b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8e39d3ecf799dfba68eabb8936223ff57adbf06830fe4280c21d268b76c8440b", kill_on_drop: false }`
[INFO] [stdout] 8e39d3ecf799dfba68eabb8936223ff57adbf06830fe4280c21d268b76c8440b