Run some rustc passes in rustdoc

src/librustdoc/core.rs

@@ -492,6 +492,7 @@ crate fn run_global_ctxt(
             tcx.ensure().check_mod_attrs(module);
         }
     });
+    rustc_passes::stability::check_unused_or_stable_features(tcx);
 
     let access_levels = tcx.privacy_access_levels(LOCAL_CRATE);
     // Convert from a HirId set to a DefId set since we don't always have easy access

src/librustdoc/lib.rs

@@ -49,6 +49,7 @@ extern crate rustc_metadata;
 extern crate rustc_middle;
 extern crate rustc_mir;
 extern crate rustc_parse;
+extern crate rustc_passes;
 extern crate rustc_resolve;
 extern crate rustc_session;
 extern crate rustc_span as rustc_span;