[INFO] fetching crate sp-rpc 2.0.1...
[INFO] checking sp-rpc-2.0.1 against try#9cfe725f0995b018340c519db1b2f3cf8a7e0631 for pr-81174
[INFO] extracting crate sp-rpc 2.0.1 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate sp-rpc 2.0.1 on toolchain 9cfe725f0995b018340c519db1b2f3cf8a7e0631
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate sp-rpc 2.0.1
[INFO] finished tweaking crates.io crate sp-rpc 2.0.1
[INFO] tweaked toml for crates.io crate sp-rpc 2.0.1 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "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-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] dcaee5cd33aa2e31ab6e20d3757ee13a95cad72b402b0fb4cc2d5f77d9d16957
[INFO] running `Command { std: "docker" "start" "-a" "dcaee5cd33aa2e31ab6e20d3757ee13a95cad72b402b0fb4cc2d5f77d9d16957", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "dcaee5cd33aa2e31ab6e20d3757ee13a95cad72b402b0fb4cc2d5f77d9d16957", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dcaee5cd33aa2e31ab6e20d3757ee13a95cad72b402b0fb4cc2d5f77d9d16957", kill_on_drop: false }`
[INFO] [stdout] dcaee5cd33aa2e31ab6e20d3757ee13a95cad72b402b0fb4cc2d5f77d9d16957
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3f58248d517bda4151cbf3f2130cba5ec971797c7163613c9c977039816205c5
[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" "3f58248d517bda4151cbf3f2130cba5ec971797c7163613c9c977039816205c5", kill_on_drop: false }`
[INFO] [stderr]    Compiling parity-util-mem v0.7.0
[INFO] [stderr]     Checking hash-db v0.15.2
[INFO] [stderr]     Checking parking_lot v0.11.1
[INFO] [stderr]     Checking libsecp256k1 v0.3.5
[INFO] [stderr]     Checking sp-storage v2.0.1
[INFO] [stderr]     Checking primitive-types v0.7.3
[INFO] [stderr]     Checking once_cell v1.5.2
[INFO] [stderr]     Checking thread_local v1.1.2
[INFO] [stderr]     Checking futures-task v0.3.12
[INFO] [stderr]     Checking tiny-bip39 v0.7.3
[INFO] [stderr]     Checking sp-externalities v0.8.1
[INFO] [stderr]     Checking futures-util v0.3.12
[INFO] [stderr]     Checking regex v1.4.3
[INFO] [stderr]     Checking tracing-subscriber v0.2.15
[INFO] [stderr]    Compiling Inflector v0.11.4
[INFO] [stderr]     Checking sp-tracing v2.0.1
[INFO] [stderr]     Checking futures-executor v0.3.12
[INFO] [stderr]     Checking futures v0.3.12
[INFO] [stderr]    Compiling sp-runtime-interface-proc-macro v2.0.1
[INFO] [stderr]     Checking sp-runtime-interface v2.0.1
[INFO] [stderr]     Checking sp-core v2.0.1
[INFO] [stderr]     Checking sp-rpc v2.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate 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 crate or module `serde_json`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate 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 crate 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" "3f58248d517bda4151cbf3f2130cba5ec971797c7163613c9c977039816205c5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3f58248d517bda4151cbf3f2130cba5ec971797c7163613c9c977039816205c5", kill_on_drop: false }`
[INFO] [stdout] 3f58248d517bda4151cbf3f2130cba5ec971797c7163613c9c977039816205c5