The following crates required explicit downgrades:
arrayvec v0.4.12 -> v0.4.11
autocfg v0.1.7 -> v0.1.6
c2-chacha v0.2.3 -> v0.2.2
ppv-lite86 v0.2.6 -> v0.2.5
proc-macro2 v1.0.10 -> v1.0.3
error: no matching package named `quote` found
location searched: registry `https://github.com/rust-lang/crates.io-index`
required by package `ff_derive v0.6.0`
... which is depended on by `ff v0.6.0`
... which is depended on by `bellman v0.6.0`
... which is depended on by `librustzcash v0.2.0 (/home/nuttycom/work/zcash)`
This enables IDE integration to work (which requires the Cargo.toml to
be in the repo root).
"make clean" no longer runs "cargo clean", because IDE integrations hold
locks on files within the Rust build directory, and an error inside
"cargo clean" error would prevent "make clean" from completing (and
removing other files).