[INFO] fetching crate sp-rpc 2.0.0-rc5...
[INFO] checking sp-rpc-2.0.0-rc5 against try#353a0a223066e9f46a1d935f2271a26c3c5002bb for pr-75180
[INFO] extracting crate sp-rpc 2.0.0-rc5 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate sp-rpc 2.0.0-rc5 on toolchain 353a0a223066e9f46a1d935f2271a26c3c5002bb
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+353a0a223066e9f46a1d935f2271a26c3c5002bb" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate sp-rpc 2.0.0-rc5
[INFO] finished tweaking crates.io crate sp-rpc 2.0.0-rc5
[INFO] tweaked toml for crates.io crate sp-rpc 2.0.0-rc5 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+353a0a223066e9f46a1d935f2271a26c3c5002bb" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+353a0a223066e9f46a1d935f2271a26c3c5002bb" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+353a0a223066e9f46a1d935f2271a26c3c5002bb" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5bb1a16cf5df533af7fb3122b2dbe4c8f107fd0be2ab60cf10abb28079ccdd6c
[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" "5bb1a16cf5df533af7fb3122b2dbe4c8f107fd0be2ab60cf10abb28079ccdd6c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5bb1a16cf5df533af7fb3122b2dbe4c8f107fd0be2ab60cf10abb28079ccdd6c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5bb1a16cf5df533af7fb3122b2dbe4c8f107fd0be2ab60cf10abb28079ccdd6c", kill_on_drop: false }`
[INFO] [stdout] 5bb1a16cf5df533af7fb3122b2dbe4c8f107fd0be2ab60cf10abb28079ccdd6c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+353a0a223066e9f46a1d935f2271a26c3c5002bb" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2c59af8f4285866516b1bbd9ec33efac8aff1fb723f5a7c4ef4f6866df8baaf7
[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" "2c59af8f4285866516b1bbd9ec33efac8aff1fb723f5a7c4ef4f6866df8baaf7", kill_on_drop: false }`
[INFO] [stderr]     Checking either v1.6.0
[INFO] [stderr]    Compiling parity-util-mem v0.7.0
[INFO] [stderr]     Checking hash-db v0.15.2
[INFO] [stderr]     Checking libsecp256k1 v0.3.5
[INFO] [stderr]     Checking bitvec v0.17.4
[INFO] [stderr]     Checking parity-scale-codec v1.3.4
[INFO] [stderr]     Checking impl-codec v0.4.2
[INFO] [stderr]     Checking sp-storage v2.0.0-rc6
[INFO] [stderr]     Checking sp-wasm-interface v2.0.0-rc6
[INFO] [stderr]     Checking primitive-types v0.7.2
[INFO] [stderr]     Checking sp-externalities v0.8.0-rc6
[INFO] [stderr]     Checking sp-runtime-interface v2.0.0-rc6
[INFO] [stderr]     Checking sp-core v2.0.0-rc6
[INFO] [stderr]     Checking sp-rpc v2.0.0-rc5 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `serde_json`
[INFO] [stdout]   --> src/lib.rs:31:3
[INFO] [stdout]    |
[INFO] [stdout] 31 |         serde_json::from_str::<T>(s).unwrap(),
[INFO] [stdout]    |         ^^^^^^^^^^ use of undeclared type or module `serde_json`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `serde_json`
[INFO] [stdout]   --> src/lib.rs:35:3
[INFO] [stdout]    |
[INFO] [stdout] 35 |         serde_json::to_string(&expected).unwrap(),
[INFO] [stdout]    |         ^^^^^^^^^^ use of undeclared type or module `serde_json`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0433`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `sp-rpc`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "2c59af8f4285866516b1bbd9ec33efac8aff1fb723f5a7c4ef4f6866df8baaf7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2c59af8f4285866516b1bbd9ec33efac8aff1fb723f5a7c4ef4f6866df8baaf7", kill_on_drop: false }`
[INFO] [stdout] 2c59af8f4285866516b1bbd9ec33efac8aff1fb723f5a7c4ef4f6866df8baaf7