[INFO] crate generator_ext 0.1.2 is already in cache
[INFO] extracting crate generator_ext 0.1.2 into work/ex/beta-1.37-6/sources/1.36.0/reg/generator_ext/0.1.2
[INFO] extracting crate generator_ext 0.1.2 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/generator_ext/0.1.2
[INFO] validating manifest of generator_ext-0.1.2 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 generator_ext-0.1.2 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 generator_ext-0.1.2
[INFO] finished frobbing generator_ext-0.1.2
[INFO] frobbed toml for generator_ext-0.1.2 written to work/ex/beta-1.37-6/sources/1.36.0/reg/generator_ext/0.1.2/Cargo.toml
[INFO] started frobbing generator_ext-0.1.2
[INFO] finished frobbing generator_ext-0.1.2
[INFO] frobbed toml for generator_ext-0.1.2 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/generator_ext/0.1.2/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] [stderr] error: failed to select a version for the requirement `futures = "^0.2.1"`
[INFO] [stderr]   candidate versions found which didn't match: 0.1.28, 0.1.27, 0.1.26, ...
[INFO] [stderr]   location searched: crates.io index
[INFO] [stderr] required by package `generator_ext v0.1.2 (/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/reg/generator_ext/0.1.2)`
[ERROR] this task or one of its parent failed!
[ERROR] overridden task result to broken:yanked
[ERROR] caused by: crate generator_ext-0.1.2 depends on yanked crates
[ERROR]