[INFO] updating cached repository Snektron/mamba
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Snektron/mamba
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Snektron/mamba" "work/ex/beta-1.38-1/sources/1.37.0/gh/Snektron/mamba"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/Snektron/mamba'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Snektron/mamba" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Snektron/mamba"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Snektron/mamba'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 8e16034b3ed9bcf9a5a92b15d9ce65d3bcf8360e
[INFO] sha for GitHub repo Snektron/mamba: 8e16034b3ed9bcf9a5a92b15d9ce65d3bcf8360e
[INFO] validating manifest of Snektron/mamba 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 Snektron/mamba 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 Snektron/mamba
[INFO] finished frobbing Snektron/mamba
[INFO] frobbed toml for Snektron/mamba written to work/ex/beta-1.38-1/sources/1.37.0/gh/Snektron/mamba/Cargo.toml
[INFO] started frobbing Snektron/mamba
[INFO] finished frobbing Snektron/mamba
[INFO] frobbed toml for Snektron/mamba written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Snektron/mamba/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 Snektron/mamba against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Snektron/mamba:/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" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] 7696e13ae9e98659d06c80d9e61cc99a367eb8adea27e7293aa5519bc7dc54e8
[INFO] running `"docker" "start" "-a" "7696e13ae9e98659d06c80d9e61cc99a367eb8adea27e7293aa5519bc7dc54e8"`
[INFO] [stderr]    Compiling byteorder v1.3.2
[INFO] [stderr]    Compiling serde v1.0.99
[INFO] [stderr]    Compiling opaque-debug v0.2.3
[INFO] [stderr]    Compiling strsim v0.9.2
[INFO] [stderr]    Compiling ena v0.11.0
[INFO] [stderr]    Compiling digest v0.8.1
[INFO] [stderr]    Compiling string_cache_codegen v0.4.2
[INFO] [stderr]    Compiling string_cache v0.7.3
[INFO] [stderr]    Compiling block-buffer v0.7.3
[INFO] [stderr]    Compiling sha2 v0.8.0
[INFO] [stderr]    Compiling docopt v1.1.0
[INFO] [stderr]    Compiling lalrpop v0.16.3
[INFO] [stderr]    Compiling mamba v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/ast/construct.rs:188:13
[INFO] [stderr]     |
[INFO] [stderr] 188 |         let mut t = check_arms(&from, arms, &states, &alphabet)?;
[INFO] [stderr]     |             ----^
[INFO] [stderr]     |             |
[INFO] [stderr]     |             help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1m 16s
[INFO] running `"docker" "inspect" "7696e13ae9e98659d06c80d9e61cc99a367eb8adea27e7293aa5519bc7dc54e8"`
[INFO] running `"docker" "rm" "-f" "7696e13ae9e98659d06c80d9e61cc99a367eb8adea27e7293aa5519bc7dc54e8"`
[INFO] [stdout] 7696e13ae9e98659d06c80d9e61cc99a367eb8adea27e7293aa5519bc7dc54e8
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Snektron/mamba:/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" "+beta-2019-08-13" "test" "--frozen" "--no-run"`
[INFO] [stdout] 1903fd1852ad0e99b1284712350bd6b515ad7a61a50e1b938c8138ae31feb68a
[INFO] running `"docker" "start" "-a" "1903fd1852ad0e99b1284712350bd6b515ad7a61a50e1b938c8138ae31feb68a"`
[INFO] [stderr]    Compiling mamba v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/ast/construct.rs:188:13
[INFO] [stderr]     |
[INFO] [stderr] 188 |         let mut t = check_arms(&from, arms, &states, &alphabet)?;
[INFO] [stderr]     |             ----^
[INFO] [stderr]     |             |
[INFO] [stderr]     |             help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.88s
[INFO] running `"docker" "inspect" "1903fd1852ad0e99b1284712350bd6b515ad7a61a50e1b938c8138ae31feb68a"`
[INFO] running `"docker" "rm" "-f" "1903fd1852ad0e99b1284712350bd6b515ad7a61a50e1b938c8138ae31feb68a"`
[INFO] [stdout] 1903fd1852ad0e99b1284712350bd6b515ad7a61a50e1b938c8138ae31feb68a
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Snektron/mamba:/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" "+beta-2019-08-13" "test" "--frozen"`
[INFO] [stdout] 70596b2b9d12931d0da15520809c7c7f532d6c6b933d7db7325e6223a88693e2
[INFO] running `"docker" "start" "-a" "70596b2b9d12931d0da15520809c7c7f532d6c6b933d7db7325e6223a88693e2"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.12s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/mamba-8fbde6c8c234a855
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "70596b2b9d12931d0da15520809c7c7f532d6c6b933d7db7325e6223a88693e2"`
[INFO] running `"docker" "rm" "-f" "70596b2b9d12931d0da15520809c7c7f532d6c6b933d7db7325e6223a88693e2"`
[INFO] [stdout] 70596b2b9d12931d0da15520809c7c7f532d6c6b933d7db7325e6223a88693e2