[INFO] updating cached repository https://github.com/yuhangwang/copy_files-rs
[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] 28fc7a1e5d719ded63b50fc519cc32df2d7e447e
[INFO] testing yuhangwang/copy_files-rs against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyuhangwang%2Fcopy_files-rs" "work/builds/worker-3/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/yuhangwang/copy_files-rs 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/yuhangwang/copy_files-rs
[INFO] finished tweaking git repo https://github.com/yuhangwang/copy_files-rs
[INFO] tweaked toml for git repo https://github.com/yuhangwang/copy_files-rs written to work/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/yuhangwang/copy_files-rs 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-3/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-3/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] 9634a2b4f0c96f2cfa1880e4196f12e4c29f9943036e5d2a28d92ac391a1389d
[INFO] running `"docker" "start" "-a" "9634a2b4f0c96f2cfa1880e4196f12e4c29f9943036e5d2a28d92ac391a1389d"`
[INFO] [stderr]    Compiling copy_files v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0658]: use of unstable library feature 'rustc_private': this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead?
[INFO] [stderr]  --> src/main.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | extern crate serde_json;
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: for more information, see https://github.com/rust-lang/rust/issues/27812
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0658`.
[INFO] [stderr] error: Could not compile `copy_files`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "9634a2b4f0c96f2cfa1880e4196f12e4c29f9943036e5d2a28d92ac391a1389d"`
[INFO] running `"docker" "rm" "-f" "9634a2b4f0c96f2cfa1880e4196f12e4c29f9943036e5d2a28d92ac391a1389d"`
[INFO] [stdout] 9634a2b4f0c96f2cfa1880e4196f12e4c29f9943036e5d2a28d92ac391a1389d