[INFO] updating cached repository https://github.com/EmmaRamirez/rust-and-webassembly-talk
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 748cc3a6a1af9143097345bce25b9fecfdc50064
[INFO] testing EmmaRamirez/rust-and-webassembly-talk against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2FEmmaRamirez%2Frust-and-webassembly-talk" "work/builds/worker-4/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/EmmaRamirez/rust-and-webassembly-talk on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/EmmaRamirez/rust-and-webassembly-talk
[INFO] finished tweaking git repo https://github.com/EmmaRamirez/rust-and-webassembly-talk
[INFO] tweaked toml for git repo https://github.com/EmmaRamirez/rust-and-webassembly-talk written to work/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/EmmaRamirez/rust-and-webassembly-talk already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] e67dee34308b5e1fec258f6aa20dbacf66c161299a579b05a5aaddc08b254066
[INFO] running `"docker" "start" "-a" "e67dee34308b5e1fec258f6aa20dbacf66c161299a579b05a5aaddc08b254066"`
[INFO] [stderr]    Compiling proc-macro2 v0.4.12
[INFO] [stderr]    Compiling wasm-bindgen-shared v0.2.16
[INFO] [stderr]    Compiling serde_json v1.0.26
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.4.12/src/lib.rs:49:5
[INFO] [stderr]    |
[INFO] [stderr] 49 |     feature(proc_macro_raw_ident, proc_macro_span)
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'proc_macro_def_site'
[INFO] [stderr]    --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.4.12/src/unstable.rs:346:27
[INFO] [stderr]     |
[INFO] [stderr] 346 |             Span::Nightly(proc_macro::Span::def_site())
[INFO] [stderr]     |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: for more information, see https://github.com/rust-lang/rust/issues/54724
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0554, E0658.
[INFO] [stderr] For more information about an error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `proc-macro2`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "e67dee34308b5e1fec258f6aa20dbacf66c161299a579b05a5aaddc08b254066"`
[INFO] running `"docker" "rm" "-f" "e67dee34308b5e1fec258f6aa20dbacf66c161299a579b05a5aaddc08b254066"`
[INFO] [stdout] e67dee34308b5e1fec258f6aa20dbacf66c161299a579b05a5aaddc08b254066