[INFO] fetching crate mechtron-host 0.3.14...
[INFO] testing mechtron-host-0.3.14 against beta-2026-04-21 for beta-1.96-1
[INFO] extracting crate mechtron-host 0.3.14 into /workspace/builds/worker-3-tc2/source
[INFO] started tweaking crates.io crate mechtron-host 0.3.14
[INFO] finished tweaking crates.io crate mechtron-host 0.3.14
[INFO] tweaked toml for crates.io crate mechtron-host 0.3.14 written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate mechtron-host 0.3.14 on toolchain beta-2026-04-21
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "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" "+beta-2026-04-21" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 278 packages to latest compatible versions
[INFO] [stderr]       Adding bincode v1.3.3 (available: v3.0.0)
[INFO] [stderr]       Adding oneshot v0.1.13 (available: v0.2.1)
[INFO] [stderr]       Adding wasmer v2.3.0 (available: v7.1.0)
[INFO] [stderr]       Adding wasmer-compiler-singlepass v2.3.0 (available: v7.1.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 38332f0a4dfaff921d4b236b72d108c09c8ef25e76cc1741a930853c48764b19
[INFO] running `Command { std: "docker" "start" "-a" "38332f0a4dfaff921d4b236b72d108c09c8ef25e76cc1741a930853c48764b19", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "38332f0a4dfaff921d4b236b72d108c09c8ef25e76cc1741a930853c48764b19", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "38332f0a4dfaff921d4b236b72d108c09c8ef25e76cc1741a930853c48764b19", kill_on_drop: false }`
[INFO] [stdout] 38332f0a4dfaff921d4b236b72d108c09c8ef25e76cc1741a930853c48764b19
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ccf748dbc1b61e0fa5a9c0c7977eb3c9a4c31768417238d38de5ede44c624af4
[INFO] running `Command { std: "docker" "start" "-a" "ccf748dbc1b61e0fa5a9c0c7977eb3c9a4c31768417238d38de5ede44c624af4", kill_on_drop: false }`
[INFO] [stderr]    Compiling serde_core v1.0.228
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling serde v1.0.228
[INFO] [stderr]    Compiling memchr v2.8.0
[INFO] [stderr]    Compiling stable_deref_trait v1.2.1
[INFO] [stderr]    Compiling indexmap v1.9.3
[INFO] [stderr]    Compiling target-lexicon v0.12.16
[INFO] [stderr]    Compiling rkyv v0.7.46
[INFO] [stderr]    Compiling syn v2.0.117
[INFO] [stderr]    Compiling miniz_oxide v0.8.9
[INFO] [stderr]    Compiling more-asserts v0.2.2
[INFO] [stderr]    Compiling wasmparser v0.83.0
[INFO] [stderr]    Compiling scopeguard v1.2.0
[INFO] [stderr]    Compiling hashbrown v0.12.3
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling memoffset v0.6.5
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]    Compiling corosensei v0.1.4
[INFO] [stderr]    Compiling cranelift-codegen-shared v0.82.3
[INFO] [stderr]    Compiling memmap2 v0.5.10
[INFO] [stderr]    Compiling cranelift-codegen-meta v0.82.3
[INFO] [stderr]    Compiling either v1.15.0
[INFO] [stderr]    Compiling crc32fast v1.5.0
[INFO] [stderr]    Compiling fallible-iterator v0.2.0
[INFO] [stderr]    Compiling num-traits v0.2.19
[INFO] [stderr]    Compiling region v3.0.2
[INFO] [stderr]    Compiling cranelift-entity v0.82.3
[INFO] [stderr]    Compiling tinyvec v1.11.0
[INFO] [stderr]    Compiling rustix v0.38.44
[INFO] [stderr]    Compiling form_urlencoded v1.2.2
[INFO] [stderr]    Compiling regalloc v0.0.34
[INFO] [stderr]    Compiling cranelift-bforest v0.82.3
[INFO] [stderr]    Compiling lock_api v0.4.14
[INFO] [stderr]    Compiling object v0.37.3
[INFO] [stderr]    Compiling aho-corasick v1.1.4
[INFO] [stderr]    Compiling nom v7.1.3
[INFO] [stderr]    Compiling hashbrown v0.11.2
[INFO] [stderr]    Compiling leb128fmt v0.1.0
[INFO] [stderr]    Compiling linux-raw-sys v0.4.15
[INFO] [stderr]    Compiling brownstone v1.1.0
[INFO] [stderr]    Compiling wasm-encoder v0.247.0
[INFO] [stderr]    Compiling rustix v1.1.4
[INFO] [stderr]    Compiling unicode-normalization v0.1.25
[INFO] [stderr]    Compiling num-integer v0.1.46
[INFO] [stderr]    Compiling rayon v1.12.0
[INFO] [stderr]    Compiling errno v0.3.14
[INFO] [stderr]    Compiling bytecount v0.6.9
[INFO] [stderr]    Compiling joinery v2.1.0
[INFO] [stderr]    Compiling leb128 v0.2.6
[INFO] [stderr]    Compiling home v0.5.12
[INFO] [stderr]    Compiling unicode-bidi v0.3.18
[INFO] [stderr]    Compiling indent_write v2.2.0
[INFO] [stderr]    Compiling wasmer-compiler-cranelift v2.3.0
[INFO] [stderr]    Compiling bumpalo v3.20.2
[INFO] [stderr]    Compiling regex-automata v0.4.14
[INFO] [stderr]    Compiling idna v0.2.3
[INFO] [stderr]    Compiling wast v247.0.0
[INFO] [stderr] error: could not compile `syn` (lib)
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/rustwide/rustup-home/toolchains/beta-2026-04-21-x86_64-unknown-linux-gnu/bin/rustc --crate-name syn --edition=2018 /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/syn-1.0.109/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no --cfg 'feature="clone-impls"' --cfg 'feature="default"' --cfg 'feature="derive"' --cfg 'feature="extra-traits"' --cfg 'feature="full"' --cfg 'feature="parsing"' --cfg 'feature="printing"' --cfg 'feature="proc-macro"' --cfg 'feature="quote"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("clone-impls", "default", "derive", "extra-traits", "fold", "full", "parsing", "printing", "proc-macro", "quote", "test", "visit", "visit-mut"))' -C metadata=c8f758427297161c -C extra-filename=-0c8f3d8f44a3c070 --out-dir /opt/rustwide/target/debug/deps -L dependency=/opt/rustwide/target/debug/deps --extern proc_macro2=/opt/rustwide/target/debug/deps/libproc_macro2-0fa97b1aa44f5fda.rmeta --extern quote=/opt/rustwide/target/debug/deps/libquote-544fd508281ca8af.rmeta --extern unicode_ident=/opt/rustwide/target/debug/deps/libunicode_ident-423507c85e36a25a.rmeta --cap-lints allow --cap-lints=warn --cfg syn_disable_nightly_tests` (signal: 9, SIGKILL: kill)
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "ccf748dbc1b61e0fa5a9c0c7977eb3c9a4c31768417238d38de5ede44c624af4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ccf748dbc1b61e0fa5a9c0c7977eb3c9a4c31768417238d38de5ede44c624af4", kill_on_drop: false }`
[INFO] [stdout] ccf748dbc1b61e0fa5a9c0c7977eb3c9a4c31768417238d38de5ede44c624af4