[INFO] fetching crate const-concat 0.1.0...
[INFO] checking const-concat-0.1.0 against master#893fadd11a52aa26fc19c67ee1b79f03d6a1bed3 for pr-77153
[INFO] extracting crate const-concat 0.1.0 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate const-concat 0.1.0 on toolchain 893fadd11a52aa26fc19c67ee1b79f03d6a1bed3
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+893fadd11a52aa26fc19c67ee1b79f03d6a1bed3" "read-manifest" "--manifest-path" "Cargo.toml", 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-3/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+893fadd11a52aa26fc19c67ee1b79f03d6a1bed3" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+893fadd11a52aa26fc19c67ee1b79f03d6a1bed3" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+893fadd11a52aa26fc19c67ee1b79f03d6a1bed3" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0e82ef1dccbb0a0b79018cb7b984a2fcd0ba264041fd4a97e9eebfe148a0bfc2
[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" "0e82ef1dccbb0a0b79018cb7b984a2fcd0ba264041fd4a97e9eebfe148a0bfc2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0e82ef1dccbb0a0b79018cb7b984a2fcd0ba264041fd4a97e9eebfe148a0bfc2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0e82ef1dccbb0a0b79018cb7b984a2fcd0ba264041fd4a97e9eebfe148a0bfc2", kill_on_drop: false }`
[INFO] [stdout] 0e82ef1dccbb0a0b79018cb7b984a2fcd0ba264041fd4a97e9eebfe148a0bfc2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+893fadd11a52aa26fc19c67ee1b79f03d6a1bed3" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d75e044dfa4ef344c36d389dea52ae7e275cd7cf9aa66f8d24a2968d6d8bf7ba
[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" "d75e044dfa4ef344c36d389dea52ae7e275cd7cf9aa66f8d24a2968d6d8bf7ba", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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] 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] [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] [stderr] error: could not compile `const-concat`
[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[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" "d75e044dfa4ef344c36d389dea52ae7e275cd7cf9aa66f8d24a2968d6d8bf7ba", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d75e044dfa4ef344c36d389dea52ae7e275cd7cf9aa66f8d24a2968d6d8bf7ba", kill_on_drop: false }`
[INFO] [stdout] d75e044dfa4ef344c36d389dea52ae7e275cd7cf9aa66f8d24a2968d6d8bf7ba