[INFO] crate generator_ext 0.1.2 is already in cache
[INFO] extracting crate generator_ext 0.1.2 into work/ex/pr-56896/sources/master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980/reg/generator_ext/0.1.2
[INFO] extracting crate generator_ext 0.1.2 into work/ex/pr-56896/sources/try#bad365140e1e8233b42b21af70a407f14ce5fec5/reg/generator_ext/0.1.2
[INFO] validating manifest of generator_ext-0.1.2 on toolchain master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+adbfec229ce07ff4b2a7bf2d6dec2d13cb224980-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of generator_ext-0.1.2 on toolchain try#bad365140e1e8233b42b21af70a407f14ce5fec5
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+bad365140e1e8233b42b21af70a407f14ce5fec5-alt" "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/pr-56896/sources/master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980/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/pr-56896/sources/try#bad365140e1e8233b42b21af70a407f14ce5fec5/reg/generator_ext/0.1.2/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+adbfec229ce07ff4b2a7bf2d6dec2d13cb224980-alt" "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: 0.1.25, 0.1.24, 0.1.23, ...
[INFO] [stderr]   location searched: crates.io index
[INFO] [stderr] required by package `generator_ext v0.1.2 (/mnt/big/crater/work/ex/pr-56896/sources/master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980/reg/generator_ext/0.1.2)`
[ERROR] this task or one of its parent failed!
[ERROR] command `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+adbfec229ce07ff4b2a7bf2d6dec2d13cb224980-alt" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"` failed