[INFO] fetching crate core_io 0.1.20190701...
[INFO] extracting crate core_io 0.1.20190701 into work/ex/beta-1.37-6/sources/1.36.0/reg/core_io/0.1.20190701
[INFO] extracting crate core_io 0.1.20190701 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/core_io/0.1.20190701
[INFO] validating manifest of core_io-0.1.20190701 on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of core_io-0.1.20190701 on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "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-1.37-6/sources/1.36.0/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-1.37-6/sources/beta-2019-07-23/reg/core_io/0.1.20190701/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing core_io-0.1.20190701 against 1.36.0 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-5/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/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" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] 8eccf8e25a588521931dc34a61404051aacf7d4fe15673212f494af1d8df8420
[INFO] running `"docker" "start" "-a" "8eccf8e25a588521931dc34a61404051aacf7d4fe15673212f494af1d8df8420"`
[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-cddda3a8fe69895c/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:1036:5
[INFO] [stderr] stack backtrace:
[INFO] [stderr]    0:     0x5611d2816523 - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::h6485381528590a55
[INFO] [stderr]                                at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
[INFO] [stderr]    1:     0x5611d281211b - std::sys_common::backtrace::_print::h49a82ae9552e35c7
[INFO] [stderr]                                at src/libstd/sys_common/backtrace.rs:71
[INFO] [stderr]    2:     0x5611d28153b6 - std::panicking::default_hook::{{closure}}::he20974adbefcc046
[INFO] [stderr]                                at src/libstd/sys_common/backtrace.rs:59
[INFO] [stderr]                                at src/libstd/panicking.rs:197
[INFO] [stderr]    3:     0x5611d2815149 - std::panicking::default_hook::he4af6af4ac7fef7b
[INFO] [stderr]                                at src/libstd/panicking.rs:211
[INFO] [stderr]    4:     0x5611d2815a0f - std::panicking::rust_panic_with_hook::h057ff03eb4c8000f
[INFO] [stderr]                                at src/libstd/panicking.rs:474
[INFO] [stderr]    5:     0x5611d2815591 - std::panicking::continue_panic_fmt::ha6d6ae144369025b
[INFO] [stderr]                                at src/libstd/panicking.rs:381
[INFO] [stderr]    6:     0x5611d2815475 - rust_begin_unwind
[INFO] [stderr]                                at src/libstd/panicking.rs:308
[INFO] [stderr]    7:     0x5611d2829f1c - core::panicking::panic_fmt::hc4f83bfed80aeabd
[INFO] [stderr]                                at src/libcore/panicking.rs:85
[INFO] [stderr]    8:     0x5611d2829f86 - core::option::expect_failed::he602aa67d6d2d670
[INFO] [stderr]                                at src/libcore/option.rs:1036
[INFO] [stderr]    9:     0x5611d27e753c - core::option::Option<T>::expect::h9878e6cd009ea759
[INFO] [stderr]                                at /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/libcore/option.rs:314
[INFO] [stderr]   10:     0x5611d27e1ec8 - build_script_build::main::h60c5023d203adc92
[INFO] [stderr]                                at /opt/crater/workdir/build.rs:73
[INFO] [stderr]   11:     0x5611d27e886f - std::rt::lang_start::{{closure}}::h459981e4aed505a5
[INFO] [stderr]                                at /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/libstd/rt.rs:64
[INFO] [stderr]   12:     0x5611d2815462 - std::panicking::try::do_call::hc3d8373a0b215f51
[INFO] [stderr]                                at src/libstd/rt.rs:49
[INFO] [stderr]                                at src/libstd/panicking.rs:293
[INFO] [stderr]   13:     0x5611d281ba69 - __rust_maybe_catch_panic
[INFO] [stderr]                                at src/libpanic_unwind/lib.rs:85
[INFO] [stderr]   14:     0x5611d2815f1c - std::rt::lang_start_internal::he5218c8b95d395f2
[INFO] [stderr]                                at src/libstd/panicking.rs:272
[INFO] [stderr]                                at src/libstd/panic.rs:394
[INFO] [stderr]                                at src/libstd/rt.rs:48
[INFO] [stderr]   15:     0x5611d27e8848 - std::rt::lang_start::h75f19e48fa6243fc
[INFO] [stderr]                                at /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/libstd/rt.rs:64
[INFO] [stderr]   16:     0x5611d27e2a89 - main
[INFO] [stderr]   17:     0x7fa20c46f2e0 - __libc_start_main
[INFO] [stderr]   18:     0x5611d27df6e9 - _start
[INFO] [stderr]   19:                0x0 - <unknown>
[INFO] [stderr] 
[INFO] running `"docker" "inspect" "8eccf8e25a588521931dc34a61404051aacf7d4fe15673212f494af1d8df8420"`
[INFO] running `"docker" "rm" "-f" "8eccf8e25a588521931dc34a61404051aacf7d4fe15673212f494af1d8df8420"`
[INFO] [stdout] 8eccf8e25a588521931dc34a61404051aacf7d4fe15673212f494af1d8df8420