[INFO] updating cached repository archer884/function_composition
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/archer884/function_composition
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/archer884/function_composition" "work/ex/beta-1.38-1/sources/1.37.0/gh/archer884/function_composition"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/archer884/function_composition'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/archer884/function_composition" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/archer884/function_composition"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/archer884/function_composition'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 7860c50fb5ea71d5131729f3d51c4b14e2042330
[INFO] sha for GitHub repo archer884/function_composition: 7860c50fb5ea71d5131729f3d51c4b14e2042330
[INFO] validating manifest of archer884/function_composition on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of archer884/function_composition on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing archer884/function_composition
[INFO] finished frobbing archer884/function_composition
[INFO] frobbed toml for archer884/function_composition written to work/ex/beta-1.38-1/sources/1.37.0/gh/archer884/function_composition/Cargo.toml
[INFO] started frobbing archer884/function_composition
[INFO] finished frobbing archer884/function_composition
[INFO] frobbed toml for archer884/function_composition written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/archer884/function_composition/Cargo.toml
[INFO] crate archer884/function_composition already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing archer884/function_composition against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/archer884/function_composition:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] 94b85eb8b53e95efb654419f072e3c62220e17a88ae7ac590b2c4d8b0ba95186
[INFO] running `"docker" "start" "-a" "94b85eb8b53e95efb654419f072e3c62220e17a88ae7ac590b2c4d8b0ba95186"`
[INFO] [stderr]    Compiling function_composition v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/main.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(box_syntax)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/main.rs:30:57
[INFO] [stderr]    |
[INFO] [stderr] 30 | fn compose<'f, T1, T2, T3, F1, F2>(a: F1, b: F2) -> Box<Fn(T1) -> T3 + 'f>
[INFO] [stderr]    |                                                         ^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(T1) -> T3 + 'f`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(bare_trait_objects)]` on by default
[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 `function_composition`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "94b85eb8b53e95efb654419f072e3c62220e17a88ae7ac590b2c4d8b0ba95186"`
[INFO] running `"docker" "rm" "-f" "94b85eb8b53e95efb654419f072e3c62220e17a88ae7ac590b2c4d8b0ba95186"`
[INFO] [stdout] 94b85eb8b53e95efb654419f072e3c62220e17a88ae7ac590b2c4d8b0ba95186