[INFO] fetching crate syntactic_heap 0.3.1...
[INFO] testing syntactic_heap-0.3.1 against master#cdb45c87e2cd43495379f7e867e3cc15dcee9f93 for pr-145838-1
[INFO] extracting crate syntactic_heap 0.3.1 into /workspace/builds/worker-6-tc1/source
[INFO] started tweaking crates.io crate syntactic_heap 0.3.1
[INFO] finished tweaking crates.io crate syntactic_heap 0.3.1
[INFO] tweaked toml for crates.io crate syntactic_heap 0.3.1 written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate syntactic_heap 0.3.1 on toolchain cdb45c87e2cd43495379f7e867e3cc15dcee9f93
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cdb45c87e2cd43495379f7e867e3cc15dcee9f93" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cdb45c87e2cd43495379f7e867e3cc15dcee9f93" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cdb45c87e2cd43495379f7e867e3cc15dcee9f93" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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@sha256:7ad1b28ee6f5f7f699f6cf7015098d6ccdd96d6f2d78dd06228f5b4c9faf309c" "/opt/rustwide/cargo-home/bin/cargo" "+cdb45c87e2cd43495379f7e867e3cc15dcee9f93" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7221af9bec40b05d2e320bbb23b8aca1cba18f209faeca448bafb679ef85f55b
[INFO] running `Command { std: "docker" "start" "-a" "7221af9bec40b05d2e320bbb23b8aca1cba18f209faeca448bafb679ef85f55b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7221af9bec40b05d2e320bbb23b8aca1cba18f209faeca448bafb679ef85f55b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7221af9bec40b05d2e320bbb23b8aca1cba18f209faeca448bafb679ef85f55b", kill_on_drop: false }`
[INFO] [stdout] 7221af9bec40b05d2e320bbb23b8aca1cba18f209faeca448bafb679ef85f55b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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" "RUSTDOCFLAGS=--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@sha256:7ad1b28ee6f5f7f699f6cf7015098d6ccdd96d6f2d78dd06228f5b4c9faf309c" "/opt/rustwide/cargo-home/bin/cargo" "+cdb45c87e2cd43495379f7e867e3cc15dcee9f93" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9c359e6b4727ad138c7a2039f6154221e52d0ec9fd39fe2c37ad5d94a86c03d5
[INFO] running `Command { std: "docker" "start" "-a" "9c359e6b4727ad138c7a2039f6154221e52d0ec9fd39fe2c37ad5d94a86c03d5", kill_on_drop: false }`
[INFO] [stderr]    Compiling syntactic_heap v0.3.1 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.18s
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:72:2
[INFO] [stdout]    |
[INFO] [stdout] 72 |     write!(f,"[");
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 72 |     let _ = write!(f,"[");
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:74:18
[INFO] [stdout]    |
[INFO] [stdout] 74 |         if !first { write!(f,","); }
[INFO] [stdout]    |                     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 74 |         if !first { let _ = write!(f,","); }
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:76:6
[INFO] [stdout]    |
[INFO] [stdout] 76 |         write!(f,"{}",item);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 76 |         let _ = write!(f,"{}",item);
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:86:2
[INFO] [stdout]    |
[INFO] [stdout] 86 |     write!(f,"[");
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 86 |     let _ = write!(f,"[");
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:88:18
[INFO] [stdout]    |
[INFO] [stdout] 88 |         if !first { write!(f,","); }
[INFO] [stdout]    |                     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 88 |         if !first { let _ = write!(f,","); }
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:90:6
[INFO] [stdout]    |
[INFO] [stdout] 90 |         write!(f,"{:?}",item);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 90 |         let _ = write!(f,"{:?}",item);
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "9c359e6b4727ad138c7a2039f6154221e52d0ec9fd39fe2c37ad5d94a86c03d5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9c359e6b4727ad138c7a2039f6154221e52d0ec9fd39fe2c37ad5d94a86c03d5", kill_on_drop: false }`
[INFO] [stdout] 9c359e6b4727ad138c7a2039f6154221e52d0ec9fd39fe2c37ad5d94a86c03d5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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" "RUSTDOCFLAGS=--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@sha256:7ad1b28ee6f5f7f699f6cf7015098d6ccdd96d6f2d78dd06228f5b4c9faf309c" "/opt/rustwide/cargo-home/bin/cargo" "+cdb45c87e2cd43495379f7e867e3cc15dcee9f93" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f99a087d556fb1a64fa46d90f4c30f7bc2d99682cf26579fd8b1aee4f5ef0e19
[INFO] running `Command { std: "docker" "start" "-a" "f99a087d556fb1a64fa46d90f4c30f7bc2d99682cf26579fd8b1aee4f5ef0e19", kill_on_drop: false }`
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:72:2
[INFO] [stdout]    |
[INFO] [stdout] 72 |     write!(f,"[");
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 72 |     let _ = write!(f,"[");
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:74:18
[INFO] [stdout]    |
[INFO] [stdout] 74 |         if !first { write!(f,","); }
[INFO] [stdout]    |                     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 74 |         if !first { let _ = write!(f,","); }
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:76:6
[INFO] [stdout]    |
[INFO] [stdout] 76 |         write!(f,"{}",item);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 76 |         let _ = write!(f,"{}",item);
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:86:2
[INFO] [stdout]    |
[INFO] [stdout] 86 |     write!(f,"[");
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 86 |     let _ = write!(f,"[");
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:88:18
[INFO] [stdout]    |
[INFO] [stdout] 88 |         if !first { write!(f,","); }
[INFO] [stdout]    |                     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 88 |         if !first { let _ = write!(f,","); }
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:90:6
[INFO] [stdout]    |
[INFO] [stdout] 90 |         write!(f,"{:?}",item);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 90 |         let _ = write!(f,"{:?}",item);
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling syntactic_heap v0.3.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:72:2
[INFO] [stdout]    |
[INFO] [stdout] 72 |     write!(f,"[");
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 72 |     let _ = write!(f,"[");
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:74:18
[INFO] [stdout]    |
[INFO] [stdout] 74 |         if !first { write!(f,","); }
[INFO] [stdout]    |                     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 74 |         if !first { let _ = write!(f,","); }
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:76:6
[INFO] [stdout]    |
[INFO] [stdout] 76 |         write!(f,"{}",item);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 76 |         let _ = write!(f,"{}",item);
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:86:2
[INFO] [stdout]    |
[INFO] [stdout] 86 |     write!(f,"[");
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 86 |     let _ = write!(f,"[");
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:88:18
[INFO] [stdout]    |
[INFO] [stdout] 88 |         if !first { write!(f,","); }
[INFO] [stdout]    |                     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 88 |         if !first { let _ = write!(f,","); }
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:90:6
[INFO] [stdout]    |
[INFO] [stdout] 90 |         write!(f,"{:?}",item);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 90 |         let _ = write!(f,"{:?}",item);
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.60s
[INFO] running `Command { std: "docker" "inspect" "f99a087d556fb1a64fa46d90f4c30f7bc2d99682cf26579fd8b1aee4f5ef0e19", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f99a087d556fb1a64fa46d90f4c30f7bc2d99682cf26579fd8b1aee4f5ef0e19", kill_on_drop: false }`
[INFO] [stdout] f99a087d556fb1a64fa46d90f4c30f7bc2d99682cf26579fd8b1aee4f5ef0e19
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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" "RUSTDOCFLAGS=--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@sha256:7ad1b28ee6f5f7f699f6cf7015098d6ccdd96d6f2d78dd06228f5b4c9faf309c" "/opt/rustwide/cargo-home/bin/cargo" "+cdb45c87e2cd43495379f7e867e3cc15dcee9f93" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 033bc81e5bfeca09421657a55cda3ecb8ea810c048f8c481dc158cdafa72e26f
[INFO] running `Command { std: "docker" "start" "-a" "033bc81e5bfeca09421657a55cda3ecb8ea810c048f8c481dc158cdafa72e26f", kill_on_drop: false }`
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/lib.rs:72:2
[INFO] [stderr]    |
[INFO] [stderr] 72 |     write!(f,"[");
[INFO] [stderr]    |     ^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]    |
[INFO] [stderr] 72 |     let _ = write!(f,"[");
[INFO] [stderr]    |     +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/lib.rs:74:18
[INFO] [stderr]    |
[INFO] [stderr] 74 |         if !first { write!(f,","); }
[INFO] [stderr]    |                     ^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]    |
[INFO] [stderr] 74 |         if !first { let _ = write!(f,","); }
[INFO] [stderr]    |                     +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/lib.rs:76:6
[INFO] [stderr]    |
[INFO] [stderr] 76 |         write!(f,"{}",item);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]    |
[INFO] [stderr] 76 |         let _ = write!(f,"{}",item);
[INFO] [stderr]    |         +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/lib.rs:86:2
[INFO] [stderr]    |
[INFO] [stderr] 86 |     write!(f,"[");
[INFO] [stderr]    |     ^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]    |
[INFO] [stderr] 86 |     let _ = write!(f,"[");
[INFO] [stderr]    |     +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/lib.rs:88:18
[INFO] [stderr]    |
[INFO] [stderr] 88 |         if !first { write!(f,","); }
[INFO] [stderr]    |                     ^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]    |
[INFO] [stderr] 88 |         if !first { let _ = write!(f,","); }
[INFO] [stderr]    |                     +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/lib.rs:90:6
[INFO] [stderr]    |
[INFO] [stderr] 90 |         write!(f,"{:?}",item);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]    |
[INFO] [stderr] 90 |         let _ = write!(f,"{:?}",item);
[INFO] [stderr]    |         +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: `syntactic_heap` (lib) generated 6 warnings
[INFO] [stderr] warning: `syntactic_heap` (lib test) generated 6 warnings (6 duplicates)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.16s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/syntactic_heap-0fc74e6190709721)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]      Running tests/lambda_calculus.rs (/opt/rustwide/target/debug/deps/lambda_calculus-af6750a449480a76)
[INFO] [stdout] 
[INFO] [stdout] running 8 tests
[INFO] [stdout] test test_heap_01 ... ok
[INFO] [stdout] test test_clone_01 ... ok
[INFO] [stdout] test test_heap_03 ... ok
[INFO] [stdout] test test_heap_02 ... ok
[INFO] [stdout] test test_iter_02 ... ok
[INFO] [stdout] test test_iter_03 ... ok
[INFO] [stdout] test test_iter_01 ... ok
[INFO] [stdout] test test_clone_02 ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 8 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests syntactic_heap
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "033bc81e5bfeca09421657a55cda3ecb8ea810c048f8c481dc158cdafa72e26f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "033bc81e5bfeca09421657a55cda3ecb8ea810c048f8c481dc158cdafa72e26f", kill_on_drop: false }`
[INFO] [stdout] 033bc81e5bfeca09421657a55cda3ecb8ea810c048f8c481dc158cdafa72e26f