[INFO] fetching crate sp-rpc 2.0.0-alpha.3...
[INFO] checking sp-rpc-2.0.0-alpha.3 against master#e2223c94bf433fc38234d1303e88cbaf14755863 for pr-69548
[INFO] extracting crate sp-rpc 2.0.0-alpha.3 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate sp-rpc 2.0.0-alpha.3 on toolchain e2223c94bf433fc38234d1303e88cbaf14755863
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e2223c94bf433fc38234d1303e88cbaf14755863" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate sp-rpc 2.0.0-alpha.3
[INFO] finished tweaking crates.io crate sp-rpc 2.0.0-alpha.3
[INFO] tweaked toml for crates.io crate sp-rpc 2.0.0-alpha.3 written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e2223c94bf433fc38234d1303e88cbaf14755863" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e2223c94bf433fc38234d1303e88cbaf14755863" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+e2223c94bf433fc38234d1303e88cbaf14755863" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 724779dd07f3a5b1070ddea64780b1c914234e7f04734ac3c824c44e69e88273
[INFO] running `"docker" "start" "-a" "724779dd07f3a5b1070ddea64780b1c914234e7f04734ac3c824c44e69e88273"`
[INFO] [stderr]     Checking hash-db v0.15.2
[INFO] [stderr]     Checking libsecp256k1 v0.3.5
[INFO] [stderr]     Checking parity-scale-codec v1.2.0
[INFO] [stderr]     Checking impl-codec v0.4.2
[INFO] [stderr]     Checking sp-wasm-interface v2.0.0-alpha.3
[INFO] [stderr]     Checking primitive-types v0.6.2
[INFO] [stderr]     Checking sp-runtime-interface v2.0.0-alpha.3
[INFO] [stderr]     Checking parity-util-mem v0.5.1
[INFO] [stderr]     Checking sp-core v2.0.0-alpha.3
[INFO] [stderr]     Checking sp-rpc v2.0.0-alpha.3 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0433]: failed to resolve: use of undeclared type or module `serde_json`
[INFO] [stderr]   --> src/lib.rs:30:3
[INFO] [stderr]    |
[INFO] [stderr] 30 |         serde_json::from_str::<T>(s).unwrap(),
[INFO] [stderr]    |         ^^^^^^^^^^ use of undeclared type or module `serde_json`
[INFO] [stderr] 
[INFO] [stderr] error[E0433]: failed to resolve: use of undeclared type or module `serde_json`
[INFO] [stderr]   --> src/lib.rs:34:3
[INFO] [stderr]    |
[INFO] [stderr] 34 |         serde_json::to_string(&expected).unwrap(),
[INFO] [stderr]    |         ^^^^^^^^^^ use of undeclared type or module `serde_json`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0433`.
[INFO] [stderr] error: could not compile `sp-rpc`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "724779dd07f3a5b1070ddea64780b1c914234e7f04734ac3c824c44e69e88273"`
[INFO] running `"docker" "rm" "-f" "724779dd07f3a5b1070ddea64780b1c914234e7f04734ac3c824c44e69e88273"`
[INFO] [stdout] 724779dd07f3a5b1070ddea64780b1c914234e7f04734ac3c824c44e69e88273