build error: can't find crate for rustc

[grishy]

./mach build --dev

....
  Compiling data-url v0.1.0
   Completed lock_api v0.3.1 in 0.5s
   Compiling script_plugins v0.0.1 (/Users/grishy/projects/servo/components/script_plugins)
error[E0463]: can't find crate for `rustc`
  --> components/script_plugins/lib.rs:24:1
   |
24 | extern crate rustc;
   | ^^^^^^^^^^^^^^^^^^^ can't find crate

error: aborting due to previous error

For more information about this error, try `rustc --explain E0463`.
error: could not compile `script_plugins`.
warning: build failed, waiting for other jobs to finish...
   Completed semver v0.9.0 in 1.1s
   Completed core-foundation-sys v0.6.2 custom-build (run) in 0.8s
   Completed crossbeam-utils v0.6.5 in 1.2s
   Completed futures v0.1.28 in 6.2s
   Completed base64 v0.10.1 in 0.6s
   Completed data-url v0.1.0 in 0.5s
   Completed hex v0.3.2 in 1.8s
   Completed bitflags v1.2.1 custom-build (run) in 1.1s
   Completed itertools v0.8.0 in 1.8s
   Completed num-traits v0.2.4 custom-build (run) in 1.6s
   Completed serde v1.0.103 custom-build (run) in 1.8s
   Completed libc v0.2.62 custom-build (run) in 2.2s
   Completed array-init v0.0.4 in 3.5s
   Completed regex-syntax v0.6.6 in 4.5s
   Completed ucd v0.1.1 in 9.3s
error: build failed
Build FAILED in 0:08:19

➜  servo git:(master) ✗ rustc -V
rustc 1.42.0-nightly (9b98af84c 2019-12-22)

[Darkspirit]

I ran into this yesterday, too. I think this fixed it:
rustup component add rustc-dev --toolchain=nightly-2019-12-23

[jdm]

You probably don't need the explicit --toolchain argument to make that work.

[grishy]

@DarkDrek yep. It's working!