[INFO] fetching crate ast2str 1.4.1...
[INFO] checking ast2str-1.4.1 against 1.95.0 for pr-155915
[INFO] extracting crate ast2str 1.4.1 into /workspace/builds/worker-0-tc1/source
[INFO] started tweaking crates.io crate ast2str 1.4.1
[INFO] finished tweaking crates.io crate ast2str 1.4.1
[INFO] tweaked toml for crates.io crate ast2str 1.4.1 written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate ast2str 1.4.1 on toolchain 1.95.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]      Locking 22 packages to latest compatible versions
[INFO] [stderr]       Adding pretty_assertions v0.7.2 (available: v1.4.1)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded ast2str-derive v0.4.1
[INFO] [stderr]   Downloaded ast2str-lib v1.3.0
[INFO] [stderr]   Downloaded pretty_assertions v0.7.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9bd94375b5977707c88bf964c8624cc966f435e84e194cded824fb81998d5c0c
[INFO] running `Command { std: "docker" "start" "-a" "9bd94375b5977707c88bf964c8624cc966f435e84e194cded824fb81998d5c0c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9bd94375b5977707c88bf964c8624cc966f435e84e194cded824fb81998d5c0c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9bd94375b5977707c88bf964c8624cc966f435e84e194cded824fb81998d5c0c", kill_on_drop: false }`
[INFO] [stdout] 9bd94375b5977707c88bf964c8624cc966f435e84e194cded824fb81998d5c0c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6b9ea4207f958ea293994e31a8a08e80269596780db339328eaacd4b1fe86ba7
[INFO] running `Command { std: "docker" "start" "-a" "6b9ea4207f958ea293994e31a8a08e80269596780db339328eaacd4b1fe86ba7", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]     Checking ast2str-lib v1.3.0
[INFO] [stderr]     Checking diff v0.1.13
[INFO] [stderr]     Checking ansi_term v0.12.1
[INFO] [stderr]     Checking pretty_assertions v0.7.2
[INFO] [stderr]    Compiling ast2str-derive v0.4.1
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/ast2str-derive-0.4.1/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(proc_macro_diagnostic)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `ast2str-derive` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "6b9ea4207f958ea293994e31a8a08e80269596780db339328eaacd4b1fe86ba7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6b9ea4207f958ea293994e31a8a08e80269596780db339328eaacd4b1fe86ba7", kill_on_drop: false }`
[INFO] [stdout] 6b9ea4207f958ea293994e31a8a08e80269596780db339328eaacd4b1fe86ba7