use util::nodemap::{DefIdMap, FnvHashSet, FnvHashMap};
use rustc_front::hir;
-use rustc_front::hir::{Block, Crate, Item, Generics, StructField, Variant};
+use rustc_front::hir::{Crate, Item, Generics, StructField, Variant};
use rustc_front::intravisit::{self, Visitor};
use std::mem::replace;