[INFO] crate trie 0.2.0 is already in cache
[INFO] extracting crate trie 0.2.0 into work/ex/beta-1.38-1/sources/1.37.0/reg/trie/0.2.0
[INFO] extracting crate trie 0.2.0 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/trie/0.2.0
[INFO] validating manifest of trie-0.2.0 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 trie-0.2.0 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 trie-0.2.0
[INFO] finished frobbing trie-0.2.0
[INFO] frobbed toml for trie-0.2.0 written to work/ex/beta-1.38-1/sources/1.37.0/reg/trie/0.2.0/Cargo.toml
[INFO] started frobbing trie-0.2.0
[INFO] finished frobbing trie-0.2.0
[INFO] frobbed toml for trie-0.2.0 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/trie/0.2.0/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing trie-0.2.0 against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-7/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/trie/0.2.0:/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] c14587957d929f59a4f4d3aa1121f6c98f9e2bb115b071f2f8e89648f7dc979c
[INFO] running `"docker" "start" "-a" "c14587957d929f59a4f4d3aa1121f6c98f9e2bb115b071f2f8e89648f7dc979c"`
[INFO] [stderr]    Compiling bit-set v0.5.1
[INFO] [stderr]    Compiling ordered_iter v0.1.1
[INFO] [stderr]    Compiling trie v0.2.0 (/opt/crater/workdir)
[INFO] [stderr] warning[E0499]: cannot borrow `*start_node` as mutable more than once at a time
[INFO] [stderr]    --> src/map.rs:702:24
[INFO] [stderr]     |
[INFO] [stderr] 674 | fn insert<'a, T>(count: &mut usize, start_node: &'a mut TrieNode<T>, key: usize, value: T, idx: usize)
[INFO] [stderr]     |           -- lifetime `'a` defined here
[INFO] [stderr] ...
[INFO] [stderr] 692 |         External(stored_key, ref mut stored_value) if stored_key == key => {
[INFO] [stderr]     |                              -------------------- first mutable borrow occurs here
[INFO] [stderr] ...
[INFO] [stderr] 695 |             return (stored_value, Some(old_value));
[INFO] [stderr]     |                    ------------------------------- returning this value requires that `start_node.1` is borrowed for `'a`
[INFO] [stderr] ...
[INFO] [stderr] 702 |     match mem::replace(start_node, Internal(Box::new(InternalNode::new()))) {
[INFO] [stderr]     |                        ^^^^^^^^^^ second mutable borrow occurs here
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
[INFO] [stderr]     = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
[INFO] [stderr]     = note: for more information, try `rustc --explain E0729`
[INFO] [stderr] 
[INFO] [stderr] warning[E0503]: cannot use `*start_node` because it was mutably borrowed
[INFO] [stderr]    --> src/map.rs:705:17
[INFO] [stderr]     |
[INFO] [stderr] 674 | fn insert<'a, T>(count: &mut usize, start_node: &'a mut TrieNode<T>, key: usize, value: T, idx: usize)
[INFO] [stderr]     |           -- lifetime `'a` defined here
[INFO] [stderr] ...
[INFO] [stderr] 692 |         External(stored_key, ref mut stored_value) if stored_key == key => {
[INFO] [stderr]     |                              -------------------- borrow of `start_node.1` occurs here
[INFO] [stderr] ...
[INFO] [stderr] 695 |             return (stored_value, Some(old_value));
[INFO] [stderr]     |                    ------------------------------- returning this value requires that `start_node.1` is borrowed for `'a`
[INFO] [stderr] ...
[INFO] [stderr] 705 |                 Internal(ref mut new_node) => {
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^ use of borrowed `start_node.1`
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
[INFO] [stderr]     = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
[INFO] [stderr]     = note: for more information, try `rustc --explain E0729`
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.60s
[INFO] running `"docker" "inspect" "c14587957d929f59a4f4d3aa1121f6c98f9e2bb115b071f2f8e89648f7dc979c"`
[INFO] running `"docker" "rm" "-f" "c14587957d929f59a4f4d3aa1121f6c98f9e2bb115b071f2f8e89648f7dc979c"`
[INFO] [stdout] c14587957d929f59a4f4d3aa1121f6c98f9e2bb115b071f2f8e89648f7dc979c
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-7/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/trie/0.2.0:/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" "+1.37.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] 5e68d91b219b27b432bd958ef248e3b8d7a1e67d5b81087649c54c03fa9e43d4
[INFO] running `"docker" "start" "-a" "5e68d91b219b27b432bd958ef248e3b8d7a1e67d5b81087649c54c03fa9e43d4"`
[INFO] [stderr]    Compiling trie v0.2.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:13:19
[INFO] [stderr]    |
[INFO] [stderr] 13 | #![cfg_attr(test, feature(fn_traits, step_by, test, unboxed_closures))]
[INFO] [stderr]    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[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 `trie`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "5e68d91b219b27b432bd958ef248e3b8d7a1e67d5b81087649c54c03fa9e43d4"`
[INFO] running `"docker" "rm" "-f" "5e68d91b219b27b432bd958ef248e3b8d7a1e67d5b81087649c54c03fa9e43d4"`
[INFO] [stdout] 5e68d91b219b27b432bd958ef248e3b8d7a1e67d5b81087649c54c03fa9e43d4