[INFO] fetching crate const-concat 0.1.0...
[INFO] testing const-concat-0.1.0 against 1.60.0 for beta-1.61-1
[INFO] extracting crate const-concat 0.1.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate const-concat 0.1.0 on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate const-concat 0.1.0
[INFO] finished tweaking crates.io crate const-concat 0.1.0
[INFO] tweaked toml for crates.io crate const-concat 0.1.0 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 34a81bef36e7c28808955573fc3cf4b895c0e91c187b63947381ed385e9bd9d7
[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" "34a81bef36e7c28808955573fc3cf4b895c0e91c187b63947381ed385e9bd9d7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "34a81bef36e7c28808955573fc3cf4b895c0e91c187b63947381ed385e9bd9d7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "34a81bef36e7c28808955573fc3cf4b895c0e91c187b63947381ed385e9bd9d7", kill_on_drop: false }`
[INFO] [stdout] 34a81bef36e7c28808955573fc3cf4b895c0e91c187b63947381ed385e9bd9d7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8be27176c348411dffe1500f87baee5f45779e80646d7d2ea55ec7e1bf8b3986
[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" "8be27176c348411dffe1500f87baee5f45779e80646d7d2ea55ec7e1bf8b3986", kill_on_drop: false }`
[INFO] [stderr]    Compiling const-concat v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(const_fn, const_str_as_bytes, const_str_len, const_let, untagged_unions)]
[INFO] [stdout]   |            ^^^^^^^^ feature has been removed
[INFO] [stdout]   |
[INFO] [stdout]   = note: split into finer-grained feature gates
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unknown lint: `unions_with_drop_fields`
[INFO] [stdout]  --> src/lib.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 | #[allow(unions_with_drop_fields)]
[INFO] [stdout]   |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unknown_lints)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[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(const_fn, const_str_as_bytes, const_str_len, const_let, untagged_unions)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `const_let` has been stable since 1.33.0 and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0740]: unions cannot contain fields that may need dropping
[INFO] [stdout]  --> src/lib.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |         from: From,
[INFO] [stdout]   |         ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type
[INFO] [stdout] help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped
[INFO] [stdout]   |
[INFO] [stdout] 6 |         from: std::mem::ManuallyDrop<From>,
[INFO] [stdout]   |               +++++++++++++++++++++++    +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0557, E0740.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `const-concat` due to 4 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "8be27176c348411dffe1500f87baee5f45779e80646d7d2ea55ec7e1bf8b3986", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8be27176c348411dffe1500f87baee5f45779e80646d7d2ea55ec7e1bf8b3986", kill_on_drop: false }`
[INFO] [stdout] 8be27176c348411dffe1500f87baee5f45779e80646d7d2ea55ec7e1bf8b3986