[INFO] crate serde_fmt 0.0.1 is already in cache
[INFO] extracting crate serde_fmt 0.0.1 into work/ex/beta-1.38-1/sources/1.37.0/reg/serde_fmt/0.0.1
[INFO] extracting crate serde_fmt 0.0.1 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/serde_fmt/0.0.1
[INFO] validating manifest of serde_fmt-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 serde_fmt-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 serde_fmt-0.0.1
[INFO] finished frobbing serde_fmt-0.0.1
[INFO] frobbed toml for serde_fmt-0.0.1 written to work/ex/beta-1.38-1/sources/1.37.0/reg/serde_fmt/0.0.1/Cargo.toml
[INFO] started frobbing serde_fmt-0.0.1
[INFO] finished frobbing serde_fmt-0.0.1
[INFO] frobbed toml for serde_fmt-0.0.1 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/serde_fmt/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 serde_fmt-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-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/serde_fmt/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] 2b45127ed2cb6894a7448238dc785115b8a906852e3ef6fbf0f9a40cc50b4983
[INFO] running `"docker" "start" "-a" "2b45127ed2cb6894a7448238dc785115b8a906852e3ef6fbf0f9a40cc50b4983"`
[INFO] [stderr]    Compiling serde v1.0.99
[INFO] [stderr]    Compiling serde_fmt 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:43:1
[INFO] [stderr]    |
[INFO] [stderr] 43 | #![feature(debug_map_key_value)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `key` found for type `core::fmt::DebugMap<'a, 'b>` in the current scope
[INFO] [stderr]    --> src/lib.rs:455:16
[INFO] [stderr]     |
[INFO] [stderr] 455 |         self.0.key(&to_debug(k));
[INFO] [stderr]     |                ^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `value` found for type `core::fmt::DebugMap<'a, 'b>` in the current scope
[INFO] [stderr]    --> src/lib.rs:463:16
[INFO] [stderr]     |
[INFO] [stderr] 463 |         self.0.value(&to_debug(v));
[INFO] [stderr]     |                ^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 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 `serde_fmt`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "2b45127ed2cb6894a7448238dc785115b8a906852e3ef6fbf0f9a40cc50b4983"`
[INFO] running `"docker" "rm" "-f" "2b45127ed2cb6894a7448238dc785115b8a906852e3ef6fbf0f9a40cc50b4983"`
[INFO] [stdout] 2b45127ed2cb6894a7448238dc785115b8a906852e3ef6fbf0f9a40cc50b4983