[INFO] fetching crate async-log 2.0.0...
[INFO] testing async-log-2.0.0 against try#722e1797249a965b6335aebd65d777f917e498f1 for pr-91031
[INFO] extracting crate async-log 2.0.0 into /workspace/builds/worker-89/source
[INFO] validating manifest of crates.io crate async-log 2.0.0 on toolchain 722e1797249a965b6335aebd65d777f917e498f1
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate async-log 2.0.0
[INFO] finished tweaking crates.io crate async-log 2.0.0
[INFO] tweaked toml for crates.io crate async-log 2.0.0 written to /workspace/builds/worker-89/source/Cargo.toml
[INFO] crate crates.io crate async-log 2.0.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded wasm-bindgen-shared v0.2.48
[INFO] [stderr]   Downloaded wasm-bindgen-macro v0.2.48
[INFO] [stderr]   Downloaded wasm-bindgen-macro-support v0.2.48
[INFO] [stderr]   Downloaded wasm-bindgen-backend v0.2.48
[INFO] [stderr]   Downloaded wasm-bindgen-webidl v0.2.48
[INFO] [stderr]   Downloaded js-sys v0.3.25
[INFO] [stderr]   Downloaded bumpalo v2.5.0
[INFO] [stderr]   Downloaded wasm-bindgen v0.2.48
[INFO] [stderr]   Downloaded femme v1.2.0
[INFO] [stderr]   Downloaded web-sys v0.3.25
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-89/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-89/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a9934f29deca4a3746c768df225964c946c2a00bcab4114874361db9d7d59e2a
[INFO] running `Command { std: "docker" "start" "-a" "a9934f29deca4a3746c768df225964c946c2a00bcab4114874361db9d7d59e2a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a9934f29deca4a3746c768df225964c946c2a00bcab4114874361db9d7d59e2a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a9934f29deca4a3746c768df225964c946c2a00bcab4114874361db9d7d59e2a", kill_on_drop: false }`
[INFO] [stdout] a9934f29deca4a3746c768df225964c946c2a00bcab4114874361db9d7d59e2a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-89/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-89/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 39febac8a64289e2f5aee88cf7efafda6e9894f425a264073cf2d8bffbcdb83a
[INFO] running `Command { std: "docker" "start" "-a" "39febac8a64289e2f5aee88cf7efafda6e9894f425a264073cf2d8bffbcdb83a", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling cc v1.0.37
[INFO] [stderr]    Compiling libc v0.2.58
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling syn v0.15.39
[INFO] [stderr]    Compiling cfg-if v0.1.9
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling rustc-demangle v0.1.15
[INFO] [stderr]    Compiling backtrace-sys v0.1.29
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]    Compiling backtrace v0.3.34
[INFO] [stderr]    Compiling async-log-attributes v1.0.1
[INFO] [stderr]    Compiling async-log v2.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: declaration of a `no_mangle` function
[INFO] [stdout]    --> src/backtrace.rs:14:1
[INFO] [stdout]     |
[INFO] [stdout] 14  | #[no_mangle]
[INFO] [stdout]     | ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]    --> src/lib.rs:106:11
[INFO] [stdout]     |
[INFO] [stdout] 106 | #![forbid(unsafe_code, future_incompatible, rust_2018_idioms)]
[INFO] [stdout]     |           ^^^^^^^^^^^
[INFO] [stdout]     = note: the linker's behavior with multiple libraries exporting duplicate symbol names is undefined and Rust cannot provide guarantees when you manually override them
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `async-log` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "39febac8a64289e2f5aee88cf7efafda6e9894f425a264073cf2d8bffbcdb83a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "39febac8a64289e2f5aee88cf7efafda6e9894f425a264073cf2d8bffbcdb83a", kill_on_drop: false }`
[INFO] [stdout] 39febac8a64289e2f5aee88cf7efafda6e9894f425a264073cf2d8bffbcdb83a