[INFO] cloning repository https://github.com/donkomura/rustlings
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/donkomura/rustlings" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdonkomura%2Frustlings", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdonkomura%2Frustlings'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 82cd8a639888d974cd22b17b3c976bf11be82bff
[INFO] building donkomura/rustlings against master#44f415c1d617ebc7b931a243b7b321ef8a6ca47c for pr-142134-abi-ast-error
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdonkomura%2Frustlings" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/donkomura/rustlings on toolchain 44f415c1d617ebc7b931a243b7b321ef8a6ca47c
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+44f415c1d617ebc7b931a243b7b321ef8a6ca47c" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/donkomura/rustlings
[INFO] finished tweaking git repo https://github.com/donkomura/rustlings
[INFO] tweaked toml for git repo https://github.com/donkomura/rustlings written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/donkomura/rustlings 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" "+44f415c1d617ebc7b931a243b7b321ef8a6ca47c" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:eea15d5475069c3ef791f10c2c6b5af2ee421ef2da1e680ecce1cba46243983b" "/opt/rustwide/cargo-home/bin/cargo" "+44f415c1d617ebc7b931a243b7b321ef8a6ca47c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 617892d022cbc8878b725bf726d7cd22c2da24b2e513fb9585c85ca41ace86c1
[INFO] running `Command { std: "docker" "start" "-a" "617892d022cbc8878b725bf726d7cd22c2da24b2e513fb9585c85ca41ace86c1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "617892d022cbc8878b725bf726d7cd22c2da24b2e513fb9585c85ca41ace86c1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "617892d022cbc8878b725bf726d7cd22c2da24b2e513fb9585c85ca41ace86c1", kill_on_drop: false }`
[INFO] [stdout] 617892d022cbc8878b725bf726d7cd22c2da24b2e513fb9585c85ca41ace86c1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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=warn" "-e" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:eea15d5475069c3ef791f10c2c6b5af2ee421ef2da1e680ecce1cba46243983b" "/opt/rustwide/cargo-home/bin/cargo" "+44f415c1d617ebc7b931a243b7b321ef8a6ca47c" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7897cc8548c443b235bbcf2c9578aa1978f7d96299f792e393ac7a1cb0dbf425
[INFO] running `Command { std: "docker" "start" "-a" "7897cc8548c443b235bbcf2c9578aa1978f7d96299f792e393ac7a1cb0dbf425", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.140
[INFO] [stderr]    Compiling proc-macro2 v1.0.53
[INFO] [stderr]    Compiling quote v1.0.26
[INFO] [stderr]    Compiling unicode-ident v1.0.8
[INFO] [stderr]    Compiling autocfg v1.1.0
[INFO] [stderr]    Compiling log v0.4.17
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling memchr v2.5.0
[INFO] [stderr]    Compiling serde_derive v1.0.158
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling serde v1.0.158
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling same-file v1.0.6
[INFO] [stderr]    Compiling regex-syntax v0.6.29
[INFO] [stderr]    Compiling unicode-width v0.1.10
[INFO] [stderr]    Compiling lazycell v1.3.0
[INFO] [stderr]    Compiling serde_json v1.0.94
[INFO] [stderr]    Compiling bitflags v1.3.2
[INFO] [stderr]    Compiling argh_shared v0.1.10
[INFO] [stderr]    Compiling walkdir v2.3.3
[INFO] [stderr]    Compiling ryu v1.0.13
[INFO] [stderr]    Compiling number_prefix v0.4.0
[INFO] [stderr]    Compiling itoa v1.0.6
[INFO] [stderr]    Compiling home v0.5.4
[INFO] [stderr]    Compiling glob v0.3.1
[INFO] [stderr]    Compiling slab v0.4.8
[INFO] [stdout] error[E0635]: unknown feature `proc_macro_span_shrink`
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro2-1.0.53/src/lib.rs:92:30
[INFO] [stdout]    |
[INFO] [stdout] 92 |     feature(proc_macro_span, proc_macro_span_shrink)
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling net2 v0.2.38
[INFO] [stderr]    Compiling inotify-sys v0.1.5
[INFO] [stderr]    Compiling console v0.15.5
[INFO] [stderr]    Compiling filetime v0.2.20
[INFO] [stdout] For more information about this error, try `rustc --explain E0635`.
[INFO] [stdout] 
[INFO] [stderr]    Compiling inotify v0.7.1
[INFO] [stderr] error: could not compile `proc-macro2` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "7897cc8548c443b235bbcf2c9578aa1978f7d96299f792e393ac7a1cb0dbf425", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7897cc8548c443b235bbcf2c9578aa1978f7d96299f792e393ac7a1cb0dbf425", kill_on_drop: false }`
[INFO] [stdout] 7897cc8548c443b235bbcf2c9578aa1978f7d96299f792e393ac7a1cb0dbf425