Return early from visit_* methods

Author: ecstatic-morse

src/librustc/lib.rs

@@ -51,6 +51,7 @@
 #![feature(thread_local)]
 #![feature(trace_macros)]
 #![feature(trusted_len)]
+#![feature(try_trait)]
 #![feature(vec_remove_item)]
 #![feature(stmt_expr_attributes)]
 #![feature(integer_atomics)]