[INFO] fetching crate const-concat 0.1.0...
[INFO] checking const-concat-0.1.0 against try#7b3565da729099dbe807466fcd118fb2815986e0 for pr-81789
[INFO] extracting crate const-concat 0.1.0 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate const-concat 0.1.0 on toolchain 7b3565da729099dbe807466fcd118fb2815986e0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "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-7/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5735c5465e31db7951e5d882d5c750c7daecb52abb782938fc3c9f3feae270cf
[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" "5735c5465e31db7951e5d882d5c750c7daecb52abb782938fc3c9f3feae270cf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5735c5465e31db7951e5d882d5c750c7daecb52abb782938fc3c9f3feae270cf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5735c5465e31db7951e5d882d5c750c7daecb52abb782938fc3c9f3feae270cf", kill_on_drop: false }`
[INFO] [stdout] 5735c5465e31db7951e5d882d5c750c7daecb52abb782938fc3c9f3feae270cf
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 16a58795362f7cfcdc1f8dd67cfe53edefd0c7356f78101f394bbe57c20d3fb0
[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" "16a58795362f7cfcdc1f8dd67cfe53edefd0c7356f78101f394bbe57c20d3fb0", kill_on_drop: false }`
[INFO] [stderr]     Checking const-concat v0.1.0 (/opt/rustwide/workdir)
[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[E0740]: unions may not contain fields that need dropping
[INFO] [stdout]  --> src/lib.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |         from: From,
[INFO] [stdout]   |         ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout] note: `std::mem::ManuallyDrop` can be used to wrap the type
[INFO] [stdout]  --> src/lib.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |         from: From,
[INFO] [stdout]   |         ^^^^^^^^^^
[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 E0740`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `const-concat`
[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] [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[E0740]: unions may not contain fields that need dropping
[INFO] [stdout]  --> src/lib.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |         from: From,
[INFO] [stdout]   |         ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout] note: `std::mem::ManuallyDrop` can be used to wrap the type
[INFO] [stdout]  --> src/lib.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |         from: From,
[INFO] [stdout]   |         ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: unions in const fn are unstable
[INFO] [stdout]   --> src/lib.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     Transmute { from }.to
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #51909 <https://github.com/rust-lang/rust/issues/51909> for more information
[INFO] [stdout]    = help: add `#![feature(const_fn_union)]` to the crate attributes to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0658, E0740.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0658`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "16a58795362f7cfcdc1f8dd67cfe53edefd0c7356f78101f394bbe57c20d3fb0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "16a58795362f7cfcdc1f8dd67cfe53edefd0c7356f78101f394bbe57c20d3fb0", kill_on_drop: false }`
[INFO] [stdout] 16a58795362f7cfcdc1f8dd67cfe53edefd0c7356f78101f394bbe57c20d3fb0