[INFO] fetching crate sp-rpc 2.0.0...
[INFO] testing sp-rpc-2.0.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate sp-rpc 2.0.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate sp-rpc 2.0.0 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate sp-rpc 2.0.0
[INFO] finished tweaking crates.io crate sp-rpc 2.0.0
[INFO] tweaked toml for crates.io crate sp-rpc 2.0.0 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "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-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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d74e14f9b2fcd833ecb6312c6957d5c66ff16a4db3d560ab32ff9d7943b1c5ce
[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" "d74e14f9b2fcd833ecb6312c6957d5c66ff16a4db3d560ab32ff9d7943b1c5ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d74e14f9b2fcd833ecb6312c6957d5c66ff16a4db3d560ab32ff9d7943b1c5ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d74e14f9b2fcd833ecb6312c6957d5c66ff16a4db3d560ab32ff9d7943b1c5ce", kill_on_drop: false }`
[INFO] [stdout] d74e14f9b2fcd833ecb6312c6957d5c66ff16a4db3d560ab32ff9d7943b1c5ce
[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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", 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] be4b7e0a5aefec948ff76f0af37980dfa2a1015236602f216bf052055cd9d724
[INFO] running `Command { std: "docker" "start" "-a" "be4b7e0a5aefec948ff76f0af37980dfa2a1015236602f216bf052055cd9d724", kill_on_drop: false }`
[INFO] [stderr]    Compiling parity-util-mem v0.7.0
[INFO] [stderr]    Compiling sp-core v2.0.0
[INFO] [stderr]    Compiling sp-rpc v2.0.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 9.42s
[INFO] running `Command { std: "docker" "inspect" "be4b7e0a5aefec948ff76f0af37980dfa2a1015236602f216bf052055cd9d724", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "be4b7e0a5aefec948ff76f0af37980dfa2a1015236602f216bf052055cd9d724", kill_on_drop: false }`
[INFO] [stdout] be4b7e0a5aefec948ff76f0af37980dfa2a1015236602f216bf052055cd9d724
[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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen" "--no-run" "--message-format=json", 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] f80d3889d93d41ed6e2fa00ea4dfb4e28dd5d112754502075326ce57ca6aa61d
[INFO] running `Command { std: "docker" "start" "-a" "f80d3889d93d41ed6e2fa00ea4dfb4e28dd5d112754502075326ce57ca6aa61d", kill_on_drop: false }`
[INFO] [stderr]    Compiling sp-rpc v2.0.0 (/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" "f80d3889d93d41ed6e2fa00ea4dfb4e28dd5d112754502075326ce57ca6aa61d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f80d3889d93d41ed6e2fa00ea4dfb4e28dd5d112754502075326ce57ca6aa61d", kill_on_drop: false }`
[INFO] [stdout] f80d3889d93d41ed6e2fa00ea4dfb4e28dd5d112754502075326ce57ca6aa61d