[nll] librustc_resolve: enable feature(nll) for bootstrap

Author: memoryruins

src/librustc_resolve/lib.rs

@@ -13,6 +13,7 @@
       html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(crate_visibility_modifier)]
+#![cfg_attr(not(stage0), feature(nll))]
 #![feature(rustc_diagnostic_macros)]
 #![feature(slice_sort_by_cached_key)]