Remove regex dependency from clippy_dev

Author: Jarcho

clippy_dev/Cargo.toml

@@ -9,10 +9,14 @@ clap = "2.33"
 indoc = "1.0"
 itertools = "0.10.1"
 opener = "0.5"
-regex = "1.5"
 shell-escape = "0.1"
 walkdir = "2.3"
 cargo_metadata = "0.14"
 
+
 [features]
 deny-warnings = []
+
+[package.metadata.rust-analyzer]
+# This package uses #[feature(rustc_private)]
+rustc_private = true

clippy_dev/src/lib.rs

@@ -1,8 +1,11 @@
 #![feature(once_cell)]
+#![feature(rustc_private)]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
 
+extern crate rustc_lexer;
+
 use std::path::PathBuf;
 
 pub mod bless;