[INFO] cloning repository https://github.com/BlackJackX/json-parser-contract
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/BlackJackX/json-parser-contract" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBlackJackX%2Fjson-parser-contract", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBlackJackX%2Fjson-parser-contract'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e5a4177d5da20333b576a8f8bbcfa14804187879
[INFO] testing BlackJackX/json-parser-contract against 1.54.0 for beta-1.55-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBlackJackX%2Fjson-parser-contract" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/BlackJackX/json-parser-contract on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-2/source/.cargo/config
[INFO] removed /workspace/builds/worker-2/source/rust-toolchain
[INFO] started tweaking git repo https://github.com/BlackJackX/json-parser-contract
[INFO] finished tweaking git repo https://github.com/BlackJackX/json-parser-contract
[INFO] tweaked toml for git repo https://github.com/BlackJackX/json-parser-contract written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/BlackJackX/json-parser-contract already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a38d58093ddcf18f52a1273ef672f51e3a2aefec0367a9f560ee8c906ae201d8
[INFO] running `Command { std: "docker" "start" "-a" "a38d58093ddcf18f52a1273ef672f51e3a2aefec0367a9f560ee8c906ae201d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a38d58093ddcf18f52a1273ef672f51e3a2aefec0367a9f560ee8c906ae201d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a38d58093ddcf18f52a1273ef672f51e3a2aefec0367a9f560ee8c906ae201d8", kill_on_drop: false }`
[INFO] [stdout] a38d58093ddcf18f52a1273ef672f51e3a2aefec0367a9f560ee8c906ae201d8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8310bbac9f09131c85e30613e7fbdcca43e9326e577260ff3783c69be348ae29
[INFO] running `Command { std: "docker" "start" "-a" "8310bbac9f09131c85e30613e7fbdcca43e9326e577260ff3783c69be348ae29", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling crunchy v0.2.2
[INFO] [stderr]    Compiling libc v0.2.72
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling proc-macro2 v1.0.18
[INFO] [stderr]    Compiling wee_alloc v0.4.5
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling static_assertions v0.2.5
[INFO] [stderr]    Compiling memory_units v0.4.0
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling syn v1.0.34
[INFO] [stderr]    Compiling rustc-hex v2.1.0
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling serde v1.0.114
[INFO] [stderr]    Compiling serde_json v1.0.56
[INFO] [stderr]    Compiling serde_derive v1.0.114
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling itoa v0.4.6
[INFO] [stderr]    Compiling spin v0.5.2
[INFO] [stderr]    Compiling very-simple-json-parser v0.1.0 (/opt/rustwide/workdir/very-simple-json-parser)
[INFO] [stdout] warning: unused variable: `len`
[INFO] [stdout]   --> very-simple-json-parser/src/lib.rs:62:9
[INFO] [stdout]    |
[INFO] [stdout] 62 |     let len = chars.len();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_len`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling pwasm-libc v0.2.1
[INFO] [stderr]    Compiling fixed-hash v0.3.2
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling tiny-keccak v1.5.0
[INFO] [stderr]    Compiling uint v0.5.0
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling pwasm-alloc v0.4.1
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/pwasm-alloc-0.4.1/src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(allocator_api)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `pwasm-alloc`
[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] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "8310bbac9f09131c85e30613e7fbdcca43e9326e577260ff3783c69be348ae29", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8310bbac9f09131c85e30613e7fbdcca43e9326e577260ff3783c69be348ae29", kill_on_drop: false }`
[INFO] [stdout] 8310bbac9f09131c85e30613e7fbdcca43e9326e577260ff3783c69be348ae29