Build Failed

[WanderHuang]

I have tried @nlopes' suggestion but i still get errors when building racer.

rustup 1.23.0 (00924c9ba 2020-11-27)
rustc 1.50.0-nightly (6a889570e 2020-11-27)
cargo 1.50.0-nightly (bfca1cd22 2020-11-24)

Error when running cargo +nightly install racer:

   Compiling rustc-ap-rustc_data_structures v686.0.0
error[E0557]: feature has been removed
  --> /home/polensky/.cargo/registry/src/github.com-1ecc6299db9ec823/rustc-ap-rustc_data_structures-686.0.0/src/lib.rs:18:12
   |
18 | #![feature(optin_builtin_traits)]
   |            ^^^^^^^^^^^^^^^^^^^^ feature has been removed
   |
   = note: renamed to `auto_traits`

error[E0658]: auto traits are experimental and possibly buggy
  --> /home/polensky/.cargo/registry/src/github.com-1ecc6299db9ec823/rustc-ap-rustc_data_structures-686.0.0/src/sync.rs:30:9
   |
30 |         pub auto trait Send {}
   |         ^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #13231 <https://github.com/rust-lang/rust/issues/13231> for more information
   = help: add `#![feature(auto_traits)]` to the crate attributes to enable

error[E0658]: auto traits are experimental and possibly buggy
  --> /home/polensky/.cargo/registry/src/github.com-1ecc6299db9ec823/rustc-ap-rustc_data_structures-686.0.0/src/sync.rs:31:9
   |
31 |         pub auto trait Sync {}
   |         ^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #13231 <https://github.com/rust-lang/rust/issues/13231> for more information
   = help: add `#![feature(auto_traits)]` to the crate attributes to enable

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0557, E0658.
For more information about an error, try `rustc --explain E0557`.
error: could not compile `rustc-ap-rustc_data_structures`

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: failed to compile `racer v2.1.40`, intermediate artifacts can be found at `/tmp/cargo-installN6A2q8`

Caused by:
  build failed

Originally posted by @Polensky in #1141 (comment)

[WanderHuang]

sorry to open this