[INFO] cloning repository https://github.com/w3rc/rust_json_writer
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/w3rc/rust_json_writer" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fw3rc%2Frust_json_writer", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fw3rc%2Frust_json_writer'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 6b41376b096066f331996ed909053f4d95eba01a
[INFO] checking w3rc/rust_json_writer against try#70daa2c0d8eed7066b07966f3c0b0b8622bff4e4 for pr-151539
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fw3rc%2Frust_json_writer" "/workspace/builds/worker-3-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/w3rc/rust_json_writer
[INFO] finished tweaking git repo https://github.com/w3rc/rust_json_writer
[INFO] tweaked toml for git repo https://github.com/w3rc/rust_json_writer written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/w3rc/rust_json_writer on toolchain 70daa2c0d8eed7066b07966f3c0b0b8622bff4e4
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+70daa2c0d8eed7066b07966f3c0b0b8622bff4e4" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/w3rc/rust_json_writer already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+70daa2c0d8eed7066b07966f3c0b0b8622bff4e4" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:61361fe0aef631f17e9d025a70c5a647956f8c671dd02950a60ad3f5cc5526d7" "/opt/rustwide/cargo-home/bin/cargo" "+70daa2c0d8eed7066b07966f3c0b0b8622bff4e4" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 85d9e8fcea4c24e8a56697852f6c21578cd67daf8b32b4df18017654003ca47b
[INFO] running `Command { std: "docker" "start" "-a" "85d9e8fcea4c24e8a56697852f6c21578cd67daf8b32b4df18017654003ca47b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "85d9e8fcea4c24e8a56697852f6c21578cd67daf8b32b4df18017654003ca47b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "85d9e8fcea4c24e8a56697852f6c21578cd67daf8b32b4df18017654003ca47b", kill_on_drop: false }`
[INFO] [stdout] 85d9e8fcea4c24e8a56697852f6c21578cd67daf8b32b4df18017654003ca47b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:61361fe0aef631f17e9d025a70c5a647956f8c671dd02950a60ad3f5cc5526d7" "/opt/rustwide/cargo-home/bin/cargo" "+70daa2c0d8eed7066b07966f3c0b0b8622bff4e4" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b1adf75137f29140665fa88dfdd7cca82cdbc57141d63fbf944f970ad0e41423
[INFO] running `Command { std: "docker" "start" "-a" "b1adf75137f29140665fa88dfdd7cca82cdbc57141d63fbf944f970ad0e41423", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.103
[INFO] [stderr]    Compiling serde_derive v1.0.147
[INFO] [stderr]    Compiling serde v1.0.147
[INFO] [stderr]    Compiling proc-macro2 v1.0.47
[INFO] [stdout] error[E0635]: unknown feature `proc_macro_span_shrink`
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro2-1.0.47/src/lib.rs:92:30
[INFO] [stdout]    |
[INFO] [stdout] 92 |     feature(proc_macro_span, proc_macro_span_shrink)
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout] help: there is a feature with a similar name: `proc_macro_span_file`
[INFO] [stdout]    |
[INFO] [stdout] 92 -     feature(proc_macro_span, proc_macro_span_shrink)
[INFO] [stdout] 92 +     feature(proc_macro_span, proc_macro_span_file)
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0635`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `proc-macro2` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "b1adf75137f29140665fa88dfdd7cca82cdbc57141d63fbf944f970ad0e41423", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b1adf75137f29140665fa88dfdd7cca82cdbc57141d63fbf944f970ad0e41423", kill_on_drop: false }`
[INFO] [stdout] b1adf75137f29140665fa88dfdd7cca82cdbc57141d63fbf944f970ad0e41423