[INFO] updating cached repository rickyhan/cargo-web-bug
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/rickyhan/cargo-web-bug
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/rickyhan/cargo-web-bug" "work/ex/pr-61753/sources/master#8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be/gh/rickyhan/cargo-web-bug"`
[INFO] [stderr] Cloning into 'work/ex/pr-61753/sources/master#8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be/gh/rickyhan/cargo-web-bug'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/rickyhan/cargo-web-bug" "work/ex/pr-61753/sources/try#af22dfc7f56a5057c6b6120a65c74e7b6c1530af/gh/rickyhan/cargo-web-bug"`
[INFO] [stderr] Cloning into 'work/ex/pr-61753/sources/try#af22dfc7f56a5057c6b6120a65c74e7b6c1530af/gh/rickyhan/cargo-web-bug'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 5af09369cb0017c46f2fc1a966b7c98a7267317a
[INFO] sha for GitHub repo rickyhan/cargo-web-bug: 5af09369cb0017c46f2fc1a966b7c98a7267317a
[INFO] validating manifest of rickyhan/cargo-web-bug on toolchain master#8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of rickyhan/cargo-web-bug on toolchain try#af22dfc7f56a5057c6b6120a65c74e7b6c1530af
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+af22dfc7f56a5057c6b6120a65c74e7b6c1530af-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing rickyhan/cargo-web-bug
[INFO] finished frobbing rickyhan/cargo-web-bug
[INFO] frobbed toml for rickyhan/cargo-web-bug written to work/ex/pr-61753/sources/master#8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be/gh/rickyhan/cargo-web-bug/Cargo.toml
[INFO] started frobbing rickyhan/cargo-web-bug
[INFO] finished frobbing rickyhan/cargo-web-bug
[INFO] frobbed toml for rickyhan/cargo-web-bug written to work/ex/pr-61753/sources/try#af22dfc7f56a5057c6b6120a65c74e7b6c1530af/gh/rickyhan/cargo-web-bug/Cargo.toml
[INFO] crate rickyhan/cargo-web-bug already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Updating git repository `https://github.com/RustPython/RustPython.git`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Updating git repository `https://github.com/OddCoincidence/unicode-casing`
[INFO] [stderr] error: failed to select a version for `syn`.
[INFO] [stderr]     ... required by package `rustpython_derive v0.1.0 (https://github.com/RustPython/RustPython.git#3f343aff)`
[INFO] [stderr]     ... which is depended on by `rustpython_vm v0.1.0 (https://github.com/RustPython/RustPython.git#3f343aff)`
[INFO] [stderr]     ... which is depended on by `cargowebbug v0.1.0 (/mnt/big/crater/work/ex/pr-61753/sources/master#8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be/gh/rickyhan/cargo-web-bug)`
[INFO] [stderr] versions that meet the requirements `^0.15.29` are: 0.15.35, 0.15.34, 0.15.33, 0.15.32, 0.15.31, 0.15.30, 0.15.29
[INFO] [stderr] 
[INFO] [stderr] all possible versions conflict with previously selected packages.
[INFO] [stderr] 
[INFO] [stderr]   previously selected package `syn v0.15.26`
[INFO] [stderr]     ... which is depended on by `failure_derive v0.1.5`
[INFO] [stderr]     ... which is depended on by `failure v0.1.5`
[INFO] [stderr]     ... which is depended on by `pwd v1.3.0`
[INFO] [stderr]     ... which is depended on by `rustpython_vm v0.1.0 (https://github.com/RustPython/RustPython.git#3f343aff)`
[INFO] [stderr]     ... which is depended on by `cargowebbug v0.1.0 (/mnt/big/crater/work/ex/pr-61753/sources/master#8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be/gh/rickyhan/cargo-web-bug)`
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `syn` which could resolve this conflict
[ERROR] this task or one of its parent failed!
[ERROR] command `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+8e948df707ea8a3c88c65bf2ffdcb2f1cf5491be-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"` failed