error: compiler plugins are experimental and possibly buggy (see issue #29597)
 --> $DIR/conf_bad_toml.rs:4:1
  |
4 | #![plugin(clippy(conf_file="../ui/conf_bad_toml.toml"))]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: add #![feature(plugin)] to the crate attributes to enable