[INFO] fetching crate fake_serialize 0.1.1...
[INFO] checking fake_serialize-0.1.1 against master#db870ea71b6dcc7a91b999420b88f41d3cdd13e1 for pr-75192
[INFO] extracting crate fake_serialize 0.1.1 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate fake_serialize 0.1.1 on toolchain db870ea71b6dcc7a91b999420b88f41d3cdd13e1
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate fake_serialize 0.1.1
[INFO] finished tweaking crates.io crate fake_serialize 0.1.1
[INFO] tweaked toml for crates.io crate fake_serialize 0.1.1 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate crates.io crate fake_serialize 0.1.1 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 26e867271efbb67fd1710fe51d5eba6abe1ddaa5b499b0157b5101def199c9f2
[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" "26e867271efbb67fd1710fe51d5eba6abe1ddaa5b499b0157b5101def199c9f2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "26e867271efbb67fd1710fe51d5eba6abe1ddaa5b499b0157b5101def199c9f2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "26e867271efbb67fd1710fe51d5eba6abe1ddaa5b499b0157b5101def199c9f2", kill_on_drop: false }`
[INFO] [stdout] 26e867271efbb67fd1710fe51d5eba6abe1ddaa5b499b0157b5101def199c9f2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7695da990b6007cec027c78bbe431a65aafba66150b4ce904bb21eb34239560b
[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" "7695da990b6007cec027c78bbe431a65aafba66150b4ce904bb21eb34239560b", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.7
[INFO] [stderr]    Compiling syn v1.0.13
[INFO] [stderr]    Compiling serde v1.0.104
[INFO] [stderr]     Checking unicode-xid v0.2.0
[INFO] [stderr]     Checking quote v1.0.2
[INFO] [stderr]    Compiling serde_derive v1.0.104
[INFO] [stderr]    Compiling fake_serialize v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `serde_json`
[INFO] [stdout]   --> examples/constraint.rs:21:20
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let json = serde_json::to_string(t).unwrap();
[INFO] [stdout]    |                    ^^^^^^^^^^ use of undeclared type or module `serde_json`
[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 E0433`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `fake_serialize`.
[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" "7695da990b6007cec027c78bbe431a65aafba66150b4ce904bb21eb34239560b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7695da990b6007cec027c78bbe431a65aafba66150b4ce904bb21eb34239560b", kill_on_drop: false }`
[INFO] [stdout] 7695da990b6007cec027c78bbe431a65aafba66150b4ce904bb21eb34239560b