[INFO] crate core_io 0.1.20190701 is already in cache
[INFO] extracting crate core_io 0.1.20190701 into work/ex/beta-1.38-1/sources/1.37.0/reg/core_io/0.1.20190701
[INFO] extracting crate core_io 0.1.20190701 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/core_io/0.1.20190701
[INFO] validating manifest of core_io-0.1.20190701 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 core_io-0.1.20190701 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 core_io-0.1.20190701
[INFO] finished frobbing core_io-0.1.20190701
[INFO] frobbed toml for core_io-0.1.20190701 written to work/ex/beta-1.38-1/sources/1.37.0/reg/core_io/0.1.20190701/Cargo.toml
[INFO] started frobbing core_io-0.1.20190701
[INFO] finished frobbing core_io-0.1.20190701
[INFO] frobbed toml for core_io-0.1.20190701 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/core_io/0.1.20190701/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 core_io-0.1.20190701 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-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/core_io/0.1.20190701:/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] 9e8de575eb4006f0481d2506f4c353854e3aa29b78ac02e5f90066705dbfc9bf
[INFO] running `"docker" "start" "-a" "9e8de575eb4006f0481d2506f4c353854e3aa29b78ac02e5f90066705dbfc9bf"`
[INFO] [stderr]    Compiling core_io v0.1.20190701 (/opt/crater/workdir)
[INFO] [stderr] error: failed to run custom build command for `core_io v0.1.20190701 (/opt/crater/workdir)`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/crater/target/debug/build/core_io-6d596bdd4dfaaa34/build-script-build` (exit code: 101)
[INFO] [stderr] --- stderr
[INFO] [stderr] thread 'main' panicked at 'Unknown compiler version, upgrade core_io?', src/libcore/option.rs:1034:5
[INFO] [stderr] stack backtrace:
[INFO] [stderr]    0:     0x55f77af430ab - backtrace::backtrace::libunwind::trace::hfe5db90796807973
[INFO] [stderr]                                at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/libunwind.rs:88
[INFO] [stderr]    1:     0x55f77af430ab - backtrace::backtrace::trace_unsynchronized::h34b865a835594335
[INFO] [stderr]                                at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/mod.rs:66
[INFO] [stderr]    2:     0x55f77af430ab - std::sys_common::backtrace::_print::h527254ae44989167
[INFO] [stderr]                                at src/libstd/sys_common/backtrace.rs:47
[INFO] [stderr]    3:     0x55f77af430ab - std::sys_common::backtrace::print::he85dd5ddddf46503
[INFO] [stderr]                                at src/libstd/sys_common/backtrace.rs:36
[INFO] [stderr]    4:     0x55f77af430ab - std::panicking::default_hook::{{closure}}::h847a2eb38b396f14
[INFO] [stderr]                                at src/libstd/panicking.rs:200
[INFO] [stderr]    5:     0x55f77af42d87 - std::panicking::default_hook::h2ca0f9a30a0e206b
[INFO] [stderr]                                at src/libstd/panicking.rs:214
[INFO] [stderr]    6:     0x55f77af43770 - std::panicking::rust_panic_with_hook::hffcefc09751839d1
[INFO] [stderr]                                at src/libstd/panicking.rs:477
[INFO] [stderr]    7:     0x55f77af432f2 - std::panicking::continue_panic_fmt::hc0f142c930c846fc
[INFO] [stderr]                                at src/libstd/panicking.rs:384
[INFO] [stderr]    8:     0x55f77af431d6 - rust_begin_unwind
[INFO] [stderr]                                at src/libstd/panicking.rs:311
[INFO] [stderr]    9:     0x55f77af5bf0d - core::panicking::panic_fmt::h2daf88b2616ca2b2
[INFO] [stderr]                                at src/libcore/panicking.rs:85
[INFO] [stderr]   10:     0x55f77af5bf77 - core::option::expect_failed::h4b77ebe6e62ec3a1
[INFO] [stderr]                                at src/libcore/option.rs:1034
[INFO] [stderr]   11:     0x55f77af15e1d - core::option::Option<T>::expect::h7affa7af45f41537
[INFO] [stderr]                                at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libcore/option.rs:314
[INFO] [stderr]   12:     0x55f77af107cb - build_script_build::main::h7ef22e3e9116a473
[INFO] [stderr]                                at /opt/crater/workdir/build.rs:73
[INFO] [stderr]   13:     0x55f77af17870 - std::rt::lang_start::{{closure}}::habece6fd585fc552
[INFO] [stderr]                                at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/rt.rs:64
[INFO] [stderr]   14:     0x55f77af431c3 - std::rt::lang_start_internal::{{closure}}::h447d8812e3ee306d
[INFO] [stderr]                                at src/libstd/rt.rs:49
[INFO] [stderr]   15:     0x55f77af431c3 - std::panicking::try::do_call::h4a61cb372364c745
[INFO] [stderr]                                at src/libstd/panicking.rs:296
[INFO] [stderr]   16:     0x55f77af4958a - __rust_maybe_catch_panic
[INFO] [stderr]                                at src/libpanic_unwind/lib.rs:82
[INFO] [stderr]   17:     0x55f77af43c7d - std::panicking::try::hdf71f938885bca42
[INFO] [stderr]                                at src/libstd/panicking.rs:275
[INFO] [stderr]   18:     0x55f77af43c7d - std::panic::catch_unwind::h7e85dbf162b1611a
[INFO] [stderr]                                at src/libstd/panic.rs:394
[INFO] [stderr]   19:     0x55f77af43c7d - std::rt::lang_start_internal::h1e06cc26b9fc25ea
[INFO] [stderr]                                at src/libstd/rt.rs:48
[INFO] [stderr]   20:     0x55f77af17849 - std::rt::lang_start::h4344ad6a98dee875
[INFO] [stderr]                                at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/rt.rs:64
[INFO] [stderr]   21:     0x55f77af1138a - main
[INFO] [stderr]   22:     0x7fa604a9e2e1 - __libc_start_main
[INFO] [stderr]   23:     0x55f77af0dffa - _start
[INFO] [stderr]   24:                0x0 - <unknown>
[INFO] [stderr] 
[INFO] running `"docker" "inspect" "9e8de575eb4006f0481d2506f4c353854e3aa29b78ac02e5f90066705dbfc9bf"`
[INFO] running `"docker" "rm" "-f" "9e8de575eb4006f0481d2506f4c353854e3aa29b78ac02e5f90066705dbfc9bf"`
[INFO] [stdout] 9e8de575eb4006f0481d2506f4c353854e3aa29b78ac02e5f90066705dbfc9bf