Depend on rustc_driver

Author: lnicola

src/tools/rust-analyzer/crates/rust-analyzer/src/bin/main.rs

@@ -3,6 +3,10 @@
 //! Based on cli flags, either spawns an LSP server, or runs a batch analysis
 
 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+#[cfg(feature = "in-rust-tree")]
+#[allow(unused_extern_crates)]
+extern crate rustc_driver;
 
 mod logger;
 mod rustc_wrapper;