[INFO] fetching crate lambda_calculus 3.0.0...
[INFO] checking lambda_calculus-3.0.0 against try#b2f80f6008cdafc35b4472bd46afa16cc6b0cd63 for pr-79470
[INFO] extracting crate lambda_calculus 3.0.0 into /workspace/builds/worker-13/source
[INFO] validating manifest of crates.io crate lambda_calculus 3.0.0 on toolchain b2f80f6008cdafc35b4472bd46afa16cc6b0cd63
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate lambda_calculus 3.0.0
[INFO] finished tweaking crates.io crate lambda_calculus 3.0.0
[INFO] tweaked toml for crates.io crate lambda_calculus 3.0.0 written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 81a098f148b59be64c25d9af241be04bdb70564de00998760789c17f8245eb1c
[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" "81a098f148b59be64c25d9af241be04bdb70564de00998760789c17f8245eb1c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "81a098f148b59be64c25d9af241be04bdb70564de00998760789c17f8245eb1c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "81a098f148b59be64c25d9af241be04bdb70564de00998760789c17f8245eb1c", kill_on_drop: false }`
[INFO] [stdout] 81a098f148b59be64c25d9af241be04bdb70564de00998760789c17f8245eb1c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c9b83e452c8d06268b80ffdd30c4db0ecf71654b9d4f2f3a4090cd4df9aa286e
[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" "c9b83e452c8d06268b80ffdd30c4db0ecf71654b9d4f2f3a4090cd4df9aa286e", kill_on_drop: false }`
[INFO] [stderr]     Checking lambda_calculus v3.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/reduction.rs:79:9
[INFO] [stdout]    |
[INFO] [stdout] 79 |         mem::replace(self, ret.unabs().unwrap()); // move unabstracted self back to its place
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/reduction.rs:123:9
[INFO] [stdout]     |
[INFO] [stdout] 123 |         mem::replace(self, lhs); // move self back to its place
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/reduction.rs:79:9
[INFO] [stdout]    |
[INFO] [stdout] 79 |         mem::replace(self, ret.unabs().unwrap()); // move unabstracted self back to its place
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/reduction.rs:123:9
[INFO] [stdout]     |
[INFO] [stdout] 123 |         mem::replace(self, lhs); // move self back to its place
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 4.48s
[INFO] running `Command { std: "docker" "inspect" "c9b83e452c8d06268b80ffdd30c4db0ecf71654b9d4f2f3a4090cd4df9aa286e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c9b83e452c8d06268b80ffdd30c4db0ecf71654b9d4f2f3a4090cd4df9aa286e", kill_on_drop: false }`
[INFO] [stdout] c9b83e452c8d06268b80ffdd30c4db0ecf71654b9d4f2f3a4090cd4df9aa286e