[INFO] updating cached repository https://github.com/Mark-Simulacrum/async-fn-size
[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] 8e79d6ce891b95c700046c3b55f0988e77fd8228
[INFO] testing Mark-Simulacrum/async-fn-size against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2FMark-Simulacrum%2Fasync-fn-size" "work/builds/worker-10/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Mark-Simulacrum/async-fn-size 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/Mark-Simulacrum/async-fn-size
[INFO] finished tweaking git repo https://github.com/Mark-Simulacrum/async-fn-size
[INFO] tweaked toml for git repo https://github.com/Mark-Simulacrum/async-fn-size written to work/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/Mark-Simulacrum/async-fn-size 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-10/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-10/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] afbcef0b74be66028971f0baa9280502cfc5ec0a57ae9e071ca6d811c398a2f6
[INFO] running `"docker" "start" "-a" "afbcef0b74be66028971f0baa9280502cfc5ec0a57ae9e071ca6d811c398a2f6"`
[INFO] [stderr]    Compiling syn v0.15.39
[INFO] [stderr]    Compiling wasm-bindgen-shared v0.2.47
[INFO] [stderr]    Compiling bumpalo v2.5.0
[INFO] [stderr]    Compiling wasm-bindgen v0.2.47
[INFO] [stderr]    Compiling wasm-bindgen-test-macro v0.2.47
[INFO] [stderr]    Compiling wasm-bindgen-backend v0.2.47
[INFO] [stderr]    Compiling wasm-bindgen-macro-support v0.2.47
[INFO] [stderr]    Compiling wasm-bindgen-macro v0.2.47
[INFO] [stderr]    Compiling js-sys v0.3.24
[INFO] [stderr]    Compiling console_error_panic_hook v0.1.6
[INFO] [stderr]    Compiling wasm-bindgen-futures v0.3.24
[INFO] [stderr]    Compiling wasm-bindgen-test v0.2.47
[INFO] [stderr]    Compiling async-fn-size v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:11:1
[INFO] [stderr]    |
[INFO] [stderr] 11 | #![feature(async_await)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `async-fn-size`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "afbcef0b74be66028971f0baa9280502cfc5ec0a57ae9e071ca6d811c398a2f6"`
[INFO] running `"docker" "rm" "-f" "afbcef0b74be66028971f0baa9280502cfc5ec0a57ae9e071ca6d811c398a2f6"`
[INFO] [stdout] afbcef0b74be66028971f0baa9280502cfc5ec0a57ae9e071ca6d811c398a2f6