Aug 02 03:57:24.089 INFO checking mwmatching-0.1.1 against 1.27.2+tmplazy for lazy_static-1
Aug 02 03:57:24.089 INFO running: cargo +1.27.2 check --frozen --all --all-targets
Aug 02 03:57:24.089 INFO creating container for: cargo +1.27.2 check --frozen --all --all-targets
Aug 02 03:57:24.090 INFO running `"docker" "create" "-v" "/tmp/crater.lROkctHgtBqn:/source:ro,Z" "-v" "/home/ec2-user/crater/./work/local/target-dirs/lazy_static-1/worker-1/1.27.2+tmplazy:/target:rw,Z" "-v" "/home/ec2-user/crater/./work/local/cargo-home:/cargo-home:ro,Z" "-v" "/home/ec2-user/crater/./work/local/rustup-home:/rustup-home:ro,Z" "-v" "/home/ec2-user/crater/./work/local/cargo-home/git:/cargo-home/git:rw,Z" "-e" "USER_ID=500" "-e" "CMD=cargo +1.27.2 check --frozen --all --all-targets" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "crater"`
Aug 02 03:57:24.319 INFO blam! 0b53505cabf69c274dc0e58efbb32c72a86af4008de4035462c121e44b99e779
Aug 02 03:57:24.320 INFO running `"docker" "start" "-a" "0b53505cabf69c274dc0e58efbb32c72a86af4008de4035462c121e44b99e779"`
Aug 02 03:57:25.324 INFO kablam!     Checking mwmatching v0.1.1 (file:///source)
Aug 02 03:57:27.400 INFO kablam! error[E0554]: #![feature] may not be used on the stable release channel
Aug 02 03:57:27.400 INFO kablam!  --> examples/largedata/main.rs:1:1
Aug 02 03:57:27.400 INFO kablam!   |
Aug 02 03:57:27.400 INFO kablam! 1 | #![feature(rustc_private)]
Aug 02 03:57:27.400 INFO kablam!   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
Aug 02 03:57:27.400 INFO kablam! 
Aug 02 03:57:27.400 INFO kablam! error: aborting due to previous error
Aug 02 03:57:27.400 INFO kablam! 
Aug 02 03:57:27.401 INFO kablam! For more information about this error, try `rustc --explain E0554`.
Aug 02 03:57:27.409 INFO kablam! error: Could not compile `mwmatching`.
Aug 02 03:57:27.409 INFO kablam! 
Aug 02 03:57:27.409 INFO kablam! To learn more, run the command again with --verbose.
Aug 02 03:57:27.411 INFO kablam! su: No module specific data is present
Aug 02 03:57:28.192 INFO running `"docker" "rm" "-f" "0b53505cabf69c274dc0e58efbb32c72a86af4008de4035462c121e44b99e779"`
Aug 02 03:57:28.350 INFO blam! 0b53505cabf69c274dc0e58efbb32c72a86af4008de4035462c121e44b99e779