Aug 02 14:25:32.229 INFO checking b64-0.4.0 against 1.27.2 for lazy_static-1
Aug 02 14:25:32.229 INFO running: cargo +1.27.2 check --frozen --all --all-targets
Aug 02 14:25:32.229 INFO creating container for: cargo +1.27.2 check --frozen --all --all-targets
Aug 02 14:25:32.230 INFO running `"docker" "create" "-v" "/tmp/crater.s0hT3Co89fNq:/source:ro,Z" "-v" "/home/ec2-user/crater/./work/local/target-dirs/lazy_static-1/worker-5/1.27.2:/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 14:25:32.474 INFO blam! 87ecfa63e459a056a3289635098a554ae60c72274729a0cf9c7d5237a8b82c46
Aug 02 14:25:32.477 INFO running `"docker" "start" "-a" "87ecfa63e459a056a3289635098a554ae60c72274729a0cf9c7d5237a8b82c46"`
Aug 02 14:25:33.630 INFO kablam!     Checking b64 v0.4.0 (file:///source)
Aug 02 14:25:35.789 INFO kablam! error[E0554]: #![feature] may not be used on the stable release channel
Aug 02 14:25:35.789 INFO kablam!  --> benches/base64.rs:1:1
Aug 02 14:25:35.789 INFO kablam!   |
Aug 02 14:25:35.790 INFO kablam! 1 | #![feature(test)]
Aug 02 14:25:35.790 INFO kablam!   | ^^^^^^^^^^^^^^^^^
Aug 02 14:25:35.790 INFO kablam! 
Aug 02 14:25:35.790 INFO kablam! error: aborting due to previous error
Aug 02 14:25:35.790 INFO kablam! 
Aug 02 14:25:35.790 INFO kablam! For more information about this error, try `rustc --explain E0554`.
Aug 02 14:25:35.796 INFO kablam! error: Could not compile `b64`.
Aug 02 14:25:35.796 INFO kablam! 
Aug 02 14:25:35.796 INFO kablam! To learn more, run the command again with --verbose.
Aug 02 14:25:35.798 INFO kablam! su: No module specific data is present
Aug 02 14:25:36.648 INFO running `"docker" "rm" "-f" "87ecfa63e459a056a3289635098a554ae60c72274729a0cf9c7d5237a8b82c46"`
Aug 02 14:25:36.806 INFO blam! 87ecfa63e459a056a3289635098a554ae60c72274729a0cf9c7d5237a8b82c46