[INFO] crate diff_fmt 0.1.0 is already in cache
[INFO] testing diff_fmt-0.1.0 against 1.44.0 for beta-1.45-1
[INFO] extracting crate diff_fmt 0.1.0 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate diff_fmt 0.1.0 on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate diff_fmt 0.1.0
[INFO] finished tweaking crates.io crate diff_fmt 0.1.0
[INFO] tweaked toml for crates.io crate diff_fmt 0.1.0 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "MAP_USER_ID=0" "-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" "+1.44.0" "build" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] f76e12ce2c1eb514b2d4d8f2df4189e091c9ccceef17c0feeaf853e7fc963783
[INFO] running `"docker" "start" "-a" "f76e12ce2c1eb514b2d4d8f2df4189e091c9ccceef17c0feeaf853e7fc963783"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling numtoa v0.1.0
[INFO] [stderr]    Compiling termion v1.5.5
[INFO] [stderr]    Compiling diff_fmt v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0433]: failed to resolve: could not find `Position` in `v1`
[INFO] [stderr]   --> src/lib.rs:40:40
[INFO] [stderr]    |
[INFO] [stderr] 40 |         position: ::core::fmt::rt::v1::Position::At(0usize),
[INFO] [stderr]    |                                        ^^^^^^^^ could not find `Position` in `v1`
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:17:1
[INFO] [stderr]    |
[INFO] [stderr] 17 | #![feature(prelude_import)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:18:1
[INFO] [stderr]    |
[INFO] [stderr] 18 | #![feature(print_internals)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:19:1
[INFO] [stderr]    |
[INFO] [stderr] 19 | #![feature(fmt_internals)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 4 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0433, E0554.
[INFO] [stderr] For more information about an error, try `rustc --explain E0433`.
[INFO] [stderr] error: could not compile `diff_fmt`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "f76e12ce2c1eb514b2d4d8f2df4189e091c9ccceef17c0feeaf853e7fc963783"`
[INFO] running `"docker" "rm" "-f" "f76e12ce2c1eb514b2d4d8f2df4189e091c9ccceef17c0feeaf853e7fc963783"`
[INFO] [stdout] f76e12ce2c1eb514b2d4d8f2df4189e091c9ccceef17c0feeaf853e7fc963783