[INFO] crate parse-regex 0.0.1 is already in cache
[INFO] extracting crate parse-regex 0.0.1 into work/ex/beta-1.38-1/sources/1.37.0/reg/parse-regex/0.0.1
[INFO] extracting crate parse-regex 0.0.1 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/parse-regex/0.0.1
[INFO] validating manifest of parse-regex-0.0.1 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 parse-regex-0.0.1 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 parse-regex-0.0.1
[INFO] finished frobbing parse-regex-0.0.1
[INFO] frobbed toml for parse-regex-0.0.1 written to work/ex/beta-1.38-1/sources/1.37.0/reg/parse-regex/0.0.1/Cargo.toml
[INFO] started frobbing parse-regex-0.0.1
[INFO] finished frobbing parse-regex-0.0.1
[INFO] frobbed toml for parse-regex-0.0.1 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/parse-regex/0.0.1/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 parse-regex-0.0.1 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-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/parse-regex/0.0.1:/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] 7f00926ab49e404c204678131001df53db49904f51cc257115d40c442d7e6857
[INFO] running `"docker" "start" "-a" "7f00926ab49e404c204678131001df53db49904f51cc257115d40c442d7e6857"`
[INFO] [stderr]    Compiling parse-regex v0.0.1 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(collections)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `char_at` found for type `std::string::String` in the current scope
[INFO] [stderr]   --> src/parser.rs:68:16
[INFO] [stderr]    |
[INFO] [stderr] 68 |         self.s.char_at(self.pos)
[INFO] [stderr]    |                ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0554, E0599.
[INFO] [stderr] For more information about an error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `parse-regex`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "7f00926ab49e404c204678131001df53db49904f51cc257115d40c442d7e6857"`
[INFO] running `"docker" "rm" "-f" "7f00926ab49e404c204678131001df53db49904f51cc257115d40c442d7e6857"`
[INFO] [stdout] 7f00926ab49e404c204678131001df53db49904f51cc257115d40c442d7e6857