diff --git a/src/libcoretest/lib.rs b/src/libcoretest/lib.rs
index aa7ab4b4e3f85..dc01a9b5c7803 100644
--- a/src/libcoretest/lib.rs
+++ b/src/libcoretest/lib.rs
@@ -15,7 +15,6 @@
 #![feature(box_syntax)]
 #![feature(cell_extras)]
 #![feature(const_fn)]
-#![feature(core_float)]
 #![feature(core_private_bignum)]
 #![feature(core_private_diy_float)]
 #![feature(dec2flt)]
diff --git a/src/libcoretest/num/mod.rs b/src/libcoretest/num/mod.rs
index 11c1bd667fb36..d5a6e0f87d69b 100644
--- a/src/libcoretest/num/mod.rs
+++ b/src/libcoretest/num/mod.rs
@@ -52,7 +52,6 @@ pub fn test_num<T>(ten: T, two: T) where
 mod tests {
     use core::option::Option;
     use core::option::Option::{Some, None};
-    use core::num::Float;
 
     #[test]
     fn from_str_issue7588() {
diff --git a/src/librand/distributions/exponential.rs b/src/librand/distributions/exponential.rs
index f02b945178fb9..12dbbfdb0ed4d 100644
--- a/src/librand/distributions/exponential.rs
+++ b/src/librand/distributions/exponential.rs
@@ -10,6 +10,7 @@
 
 //! The exponential distribution.
 
+#[cfg(not(test))] // only necessary for no_std
 use FloatMath;
 
 use {Rng, Rand};
diff --git a/src/librand/distributions/gamma.rs b/src/librand/distributions/gamma.rs
index 8cd7ac06f991b..cf48823656044 100644
--- a/src/librand/distributions/gamma.rs
+++ b/src/librand/distributions/gamma.rs
@@ -13,6 +13,7 @@
 use self::GammaRepr::*;
 use self::ChiSquaredRepr::*;
 
+#[cfg(not(test))] // only necessary for no_std
 use FloatMath;
 
 use {Rng, Open01};
diff --git a/src/librand/distributions/mod.rs b/src/librand/distributions/mod.rs
index a54c8df2352ac..2557d39c550f5 100644
--- a/src/librand/distributions/mod.rs
+++ b/src/librand/distributions/mod.rs
@@ -17,7 +17,9 @@
 //! internally. The `IndependentSample` trait is for generating values
 //! that do not need to record state.
 
+#[cfg(not(test))] // only necessary for no_std
 use core::num::Float;
+
 use core::marker::PhantomData;
 
 use {Rng, Rand};
diff --git a/src/librand/distributions/normal.rs b/src/librand/distributions/normal.rs
index b2ccc5eb6095b..86840c568e018 100644
--- a/src/librand/distributions/normal.rs
+++ b/src/librand/distributions/normal.rs
@@ -10,6 +10,7 @@
 
 //! The normal and derived distributions.
 
+#[cfg(not(test))] // only necessary for no_std
 use FloatMath;
 
 use {Rng, Rand, Open01};
diff --git a/src/librand/lib.rs b/src/librand/lib.rs
index e651f5bc1829b..d8517fb4c5714 100644
--- a/src/librand/lib.rs
+++ b/src/librand/lib.rs
@@ -28,13 +28,13 @@
 #![unstable(feature = "rand",
             reason = "use `rand` from crates.io",
             issue = "27703")]
-#![feature(core_float)]
 #![feature(core_intrinsics)]
 #![feature(staged_api)]
 #![feature(step_by)]
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
 
+#![cfg_attr(not(test), feature(core_float))] // only necessary for no_std
 #![cfg_attr(test, feature(test, rand))]
 
 #![allow(deprecated)]
diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 8378495599ce3..3e43c8e2c9355 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -59,6 +59,7 @@ pub enum DepNode<D: Clone + Debug> {
     TypeckItemBody(D),
     Dropck,
     DropckImpl(D),
+    UnusedTraitCheck,
     CheckConst(D),
     Privacy,
     IntrinsicCheck(D),
@@ -165,6 +166,7 @@ impl<D: Clone + Debug> DepNode<D> {
             CheckEntryFn => Some(CheckEntryFn),
             Variance => Some(Variance),
             Dropck => Some(Dropck),
+            UnusedTraitCheck => Some(UnusedTraitCheck),
             Privacy => Some(Privacy),
             Reachability => Some(Reachability),
             DeadCheck => Some(DeadCheck),
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index 7eaace91ae9b6..68e3e742d0316 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -1639,8 +1639,13 @@ pub type FreevarMap = NodeMap<Vec<Freevar>>;
 
 pub type CaptureModeMap = NodeMap<CaptureClause>;
 
+pub struct TraitCandidate {
+    pub def_id: DefId,
+    pub import_id: Option<NodeId>,
+}
+
 // Trait method resolution
-pub type TraitMap = NodeMap<Vec<DefId>>;
+pub type TraitMap = NodeMap<Vec<TraitCandidate>>;
 
 // Map from the NodeId of a glob import to a list of items which are actually
 // imported.
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 5bde6df5123d6..c7ae038eb7add 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -289,6 +289,8 @@ pub struct TyCtxt<'tcx> {
     // scratch every time.
     pub freevars: RefCell<FreevarMap>,
 
+    pub maybe_unused_trait_imports: NodeSet,
+
     // Records the type of every item.
     pub tcache: RefCell<DepTrackingMap<maps::Tcache<'tcx>>>,
 
@@ -338,6 +340,10 @@ pub struct TyCtxt<'tcx> {
     /// about.
     pub used_mut_nodes: RefCell<NodeSet>,
 
+    /// Set of trait imports actually used in the method resolution.
+    /// This is used for warning unused imports.
+    pub used_trait_imports: RefCell<NodeSet>,
+
     /// The set of external nominal types whose implementations have been read.
     /// This is used for lazy resolution of methods.
     pub populated_external_types: RefCell<DefIdSet>,
@@ -543,6 +549,7 @@ impl<'tcx> TyCtxt<'tcx> {
                                  named_region_map: resolve_lifetime::NamedRegionMap,
                                  map: ast_map::Map<'tcx>,
                                  freevars: FreevarMap,
+                                 maybe_unused_trait_imports: NodeSet,
                                  region_maps: RegionMaps,
                                  lang_items: middle::lang_items::LanguageItems,
                                  stability: stability::Index<'tcx>,
@@ -581,6 +588,7 @@ impl<'tcx> TyCtxt<'tcx> {
             fulfilled_predicates: RefCell::new(fulfilled_predicates),
             map: map,
             freevars: RefCell::new(freevars),
+            maybe_unused_trait_imports: maybe_unused_trait_imports,
             tcache: RefCell::new(DepTrackingMap::new(dep_graph.clone())),
             rcache: RefCell::new(FnvHashMap()),
             tc_cache: RefCell::new(FnvHashMap()),
@@ -595,6 +603,7 @@ impl<'tcx> TyCtxt<'tcx> {
             impl_items: RefCell::new(DepTrackingMap::new(dep_graph.clone())),
             used_unsafe: RefCell::new(NodeSet()),
             used_mut_nodes: RefCell::new(NodeSet()),
+            used_trait_imports: RefCell::new(NodeSet()),
             populated_external_types: RefCell::new(DefIdSet()),
             populated_external_primitive_impls: RefCell::new(DefIdSet()),
             extern_const_statics: RefCell::new(DefIdMap()),
diff --git a/src/librustc_back/sha2.rs b/src/librustc_back/sha2.rs
index 26f512e061338..404298d8839ae 100644
--- a/src/librustc_back/sha2.rs
+++ b/src/librustc_back/sha2.rs
@@ -531,7 +531,7 @@ mod tests {
     use self::rand::isaac::IsaacRng;
     use serialize::hex::FromHex;
     use std::u64;
-    use super::{Digest, Sha256, FixedBuffer};
+    use super::{Digest, Sha256};
 
     // A normal addition - no overflow occurs
     #[test]
@@ -648,7 +648,7 @@ mod tests {
 mod bench {
     extern crate test;
     use self::test::Bencher;
-    use super::{Sha256, FixedBuffer, Digest};
+    use super::{Sha256, Digest};
 
     #[bench]
     pub fn sha256_10(b: &mut Bencher) {
diff --git a/src/librustc_const_eval/eval.rs b/src/librustc_const_eval/eval.rs
index 06be29b904976..9d2922ae64033 100644
--- a/src/librustc_const_eval/eval.rs
+++ b/src/librustc_const_eval/eval.rs
@@ -17,7 +17,7 @@ use self::EvalHint::*;
 
 use rustc::hir::map as ast_map;
 use rustc::hir::map::blocks::FnLikeNode;
-use rustc::middle::cstore::{self, CrateStore, InlinedItem};
+use rustc::middle::cstore::{self, InlinedItem};
 use rustc::{infer, traits};
 use rustc::hir::def::Def;
 use rustc::hir::def_id::DefId;
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index 1b570933beecc..e791a35125233 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -791,6 +791,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
     let resolve::CrateMap {
         def_map,
         freevars,
+        maybe_unused_trait_imports,
         export_map,
         trait_map,
         glob_map,
@@ -840,6 +841,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
                              named_region_map,
                              hir_map,
                              freevars,
+                             maybe_unused_trait_imports,
                              region_map,
                              lang_items,
                              index,
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 3b25104437aee..299a20c1a0deb 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -70,7 +70,6 @@ use rustc_trans::back::link;
 use rustc::session::{self, config, Session, build_session, CompileResult};
 use rustc::session::config::{Input, PrintRequest, OutputType, ErrorOutputType};
 use rustc::session::config::{get_unstable_features_setting, nightly_options};
-use rustc::middle::cstore::CrateStore;
 use rustc::lint::Lint;
 use rustc::lint;
 use rustc_metadata::loader;
diff --git a/src/librustc_driver/test.rs b/src/librustc_driver/test.rs
index 37f7b31b69cf2..d546db086b588 100644
--- a/src/librustc_driver/test.rs
+++ b/src/librustc_driver/test.rs
@@ -24,7 +24,6 @@ use rustc::ty::subst;
 use rustc::ty::subst::Subst;
 use rustc::traits::ProjectionMode;
 use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
-use rustc::ty::relate::TypeRelation;
 use rustc::infer::{self, InferOk, InferResult, TypeOrigin};
 use rustc_metadata::cstore::CStore;
 use rustc_metadata::creader::LocalCrateReader;
@@ -132,7 +131,7 @@ fn test_env<F>(source_string: &str,
 
     // run just enough stuff to build a tcx:
     let lang_items = lang_items::collect_language_items(&sess, &ast_map);
-    let resolve::CrateMap { def_map, freevars, .. } =
+    let resolve::CrateMap { def_map, freevars, maybe_unused_trait_imports, .. } =
         resolve::resolve_crate(&sess, &ast_map, resolve::MakeGlobMap::No);
     let named_region_map = resolve_lifetime::krate(&sess, &ast_map, &def_map.borrow());
     let region_map = region::resolve_crate(&sess, &ast_map);
@@ -143,6 +142,7 @@ fn test_env<F>(source_string: &str,
                                named_region_map.unwrap(),
                                ast_map,
                                freevars,
+                               maybe_unused_trait_imports,
                                region_map,
                                lang_items,
                                index,
diff --git a/src/librustc_incremental/persist/data.rs b/src/librustc_incremental/persist/data.rs
index 60d644ba7681a..37d5f8937f174 100644
--- a/src/librustc_incremental/persist/data.rs
+++ b/src/librustc_incremental/persist/data.rs
@@ -11,7 +11,6 @@
 //! The data that we will serialize and deserialize.
 
 use rustc::dep_graph::DepNode;
-use rustc_serialize::{Decoder as RustcDecoder, Encoder as RustcEncoder};
 
 use super::directory::DefPathIndex;
 
diff --git a/src/librustc_incremental/persist/directory.rs b/src/librustc_incremental/persist/directory.rs
index 7f4c7d919c0cb..796812556d2a7 100644
--- a/src/librustc_incremental/persist/directory.rs
+++ b/src/librustc_incremental/persist/directory.rs
@@ -18,7 +18,6 @@ use rustc::hir::map::DefPath;
 use rustc::hir::def_id::DefId;
 use rustc::ty;
 use rustc::util::nodemap::DefIdMap;
-use rustc_serialize::{Decoder as RustcDecoder, Encoder as RustcEncoder};
 use std::fmt::{self, Debug};
 
 /// Index into the DefIdDirectory
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 4bdd926869a5a..6a51b1a43adfa 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -29,7 +29,6 @@
 //! a `pub fn new()`.
 
 use rustc::hir::def::Def;
-use middle::cstore::CrateStore;
 use rustc::hir::def_id::DefId;
 use middle::stability;
 use rustc::{cfg, infer};
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index 891731cb29604..b81a4a0efe741 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -26,7 +26,7 @@ use std::{i8, i16, i32, i64, u8, u16, u32, u64, f32, f64};
 
 use syntax::ast;
 use syntax::abi::Abi;
-use syntax::attr::{self, AttrMetaMethods};
+use syntax::attr;
 use syntax::codemap::{self, Span};
 
 use rustc::hir;
diff --git a/src/librustc_metadata/csearch.rs b/src/librustc_metadata/csearch.rs
index 8e7be0e3a0f5e..6a79d5df80ae2 100644
--- a/src/librustc_metadata/csearch.rs
+++ b/src/librustc_metadata/csearch.rs
@@ -536,7 +536,7 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
         let mut visible_parent_map = self.visible_parent_map.borrow_mut();
         if !visible_parent_map.is_empty() { return visible_parent_map; }
 
-        use rustc::middle::cstore::{CrateStore, ChildItem};
+        use rustc::middle::cstore::ChildItem;
         use std::collections::vec_deque::VecDeque;
         use std::collections::hash_map::Entry;
         for cnum in 1 .. self.next_crate_num() {
diff --git a/src/librustc_metadata/decoder.rs b/src/librustc_metadata/decoder.rs
index c911b20c2aba2..dd5a643edc1eb 100644
--- a/src/librustc_metadata/decoder.rs
+++ b/src/librustc_metadata/decoder.rs
@@ -43,7 +43,6 @@ use rustc::mir;
 use rustc::mir::visit::MutVisitor;
 
 use std::cell::Cell;
-use std::io::prelude::*;
 use std::io;
 use std::rc::Rc;
 use std::str;
diff --git a/src/librustc_metadata/encoder.rs b/src/librustc_metadata/encoder.rs
index 40a7f91154f97..7558e0774b362 100644
--- a/src/librustc_metadata/encoder.rs
+++ b/src/librustc_metadata/encoder.rs
@@ -21,7 +21,7 @@ use def_key;
 use tyencode;
 use index::{self, IndexData};
 
-use middle::cstore::{LOCAL_CRATE, CrateStore, InlinedItemRef, LinkMeta, tls};
+use middle::cstore::{LOCAL_CRATE, InlinedItemRef, LinkMeta, tls};
 use rustc::hir::def;
 use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
 use middle::dependency_format::Linkage;
@@ -46,7 +46,6 @@ use syntax::abi::Abi;
 use syntax::ast::{self, NodeId, Name, CRATE_NODE_ID, CrateNum};
 use syntax::codemap::BytePos;
 use syntax::attr;
-use syntax::attr::AttrMetaMethods;
 use syntax::errors::Handler;
 use syntax;
 use rbml::writer::Encoder;
diff --git a/src/librustc_metadata/loader.rs b/src/librustc_metadata/loader.rs
index 2316a67d9d3e3..4ecb7a28ef76f 100644
--- a/src/librustc_metadata/loader.rs
+++ b/src/librustc_metadata/loader.rs
@@ -233,7 +233,6 @@ use std::cmp;
 use std::collections::HashMap;
 use std::fmt;
 use std::fs;
-use std::io::prelude::*;
 use std::io;
 use std::path::{Path, PathBuf};
 use std::ptr;
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index d55d0d53b8c48..4a4b7caf478ea 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -34,7 +34,6 @@ use rustc::hir::intravisit::{self, Visitor};
 
 use rustc::dep_graph::DepNode;
 use rustc::lint;
-use rustc::middle::cstore::CrateStore;
 use rustc::hir::def::{self, Def};
 use rustc::hir::def_id::DefId;
 use rustc::middle::privacy::{AccessLevel, AccessLevels};
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index 4dc19434c8024..f5e72195bc356 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -21,7 +21,7 @@ use ParentLink::{ModuleParentLink, BlockParentLink};
 use Resolver;
 use {resolve_error, resolve_struct_error, ResolutionError};
 
-use rustc::middle::cstore::{CrateStore, ChildItem, DlDef};
+use rustc::middle::cstore::{ChildItem, DlDef};
 use rustc::lint;
 use rustc::hir::def::*;
 use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
diff --git a/src/librustc_resolve/check_unused.rs b/src/librustc_resolve/check_unused.rs
index 9135b656736a2..e213a51fb3842 100644
--- a/src/librustc_resolve/check_unused.rs
+++ b/src/librustc_resolve/check_unused.rs
@@ -16,6 +16,8 @@
 // resolve data structures and because it finalises the privacy information for
 // `use` directives.
 //
+// Unused trait imports can't be checked until the method resolution. We save
+// candidates here, and do the acutal check in librustc_typeck/check_unused.rs.
 
 use std::ops::{Deref, DerefMut};
 
@@ -55,10 +57,18 @@ impl<'a, 'b, 'tcx> UnusedImportCheckVisitor<'a, 'b, 'tcx> {
     fn check_import(&mut self, id: ast::NodeId, span: Span) {
         if !self.used_imports.contains(&(id, TypeNS)) &&
            !self.used_imports.contains(&(id, ValueNS)) {
+            if self.maybe_unused_trait_imports.contains(&id) {
+                // Check later.
+                return;
+            }
             self.session.add_lint(lint::builtin::UNUSED_IMPORTS,
                                   id,
                                   span,
                                   "unused import".to_string());
+        } else {
+            // This trait import is definitely used, in a way other than
+            // method resolution.
+            self.maybe_unused_trait_imports.remove(&id);
         }
     }
 }
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index b590cc91c5918..ff412be323a7f 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -47,18 +47,16 @@ use rustc::dep_graph::DepNode;
 use rustc::hir::map as hir_map;
 use rustc::session::Session;
 use rustc::lint;
-use rustc::middle::cstore::CrateStore;
 use rustc::hir::def::*;
 use rustc::hir::def_id::DefId;
 use rustc::hir::pat_util::pat_bindings;
 use rustc::ty;
 use rustc::ty::subst::{ParamSpace, FnSpace, TypeSpace};
-use rustc::hir::{Freevar, FreevarMap, TraitMap, GlobMap};
-use rustc::util::nodemap::{NodeMap, FnvHashMap, FnvHashSet};
+use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
+use rustc::util::nodemap::{NodeMap, NodeSet, FnvHashMap, FnvHashSet};
 
 use syntax::ast::{self, FloatTy};
 use syntax::ast::{CRATE_NODE_ID, Name, NodeId, CrateNum, IntTy, UintTy};
-use syntax::attr::AttrMetaMethods;
 use syntax::codemap::{self, Span, Pos};
 use syntax::errors::DiagnosticBuilder;
 use syntax::parse::token::{self, keywords};
@@ -1056,6 +1054,7 @@ pub struct Resolver<'a, 'tcx: 'a> {
 
     used_imports: HashSet<(NodeId, Namespace)>,
     used_crates: HashSet<CrateNum>,
+    maybe_unused_trait_imports: NodeSet,
 
     privacy_errors: Vec<PrivacyError<'a>>,
 
@@ -1151,13 +1150,15 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             export_map: NodeMap(),
             trait_map: NodeMap(),
             module_map: module_map,
-            used_imports: HashSet::new(),
-            used_crates: HashSet::new(),
 
             emit_errors: true,
             make_glob_map: make_glob_map == MakeGlobMap::Yes,
             glob_map: NodeMap(),
 
+            used_imports: HashSet::new(),
+            used_crates: HashSet::new(),
+            maybe_unused_trait_imports: NodeSet(),
+
             privacy_errors: Vec::new(),
 
             arenas: arenas,
@@ -1191,7 +1192,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
     }
 
     #[inline]
-    fn record_use(&mut self, name: Name, ns: Namespace, binding: &'a NameBinding<'a>) {
+    fn record_use(&mut self, name: Name, binding: &'a NameBinding<'a>) {
         // track extern crates for unused_extern_crate lint
         if let Some(DefId { krate, .. }) = binding.module().and_then(ModuleS::def_id) {
             self.used_crates.insert(krate);
@@ -1203,7 +1204,6 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             _ => return,
         };
 
-        self.used_imports.insert((directive.id, ns));
         if let Some(error) = privacy_error.as_ref() {
             self.privacy_errors.push((**error).clone());
         }
@@ -1506,7 +1506,10 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             false => module.resolve_name(name, namespace, false),
         }.and_then(|binding| {
             if record_used {
-                self.record_use(name, namespace, binding);
+                if let NameBindingKind::Import { directive, .. } = binding.kind {
+                    self.used_imports.insert((directive.id, namespace));
+                }
+                self.record_use(name, binding);
             }
             Success(binding)
         })
@@ -3110,21 +3113,27 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         }
     }
 
-    fn get_traits_containing_item(&mut self, name: Name) -> Vec<DefId> {
+    fn get_traits_containing_item(&mut self, name: Name) -> Vec<TraitCandidate> {
         debug!("(getting traits containing item) looking for '{}'", name);
 
-        fn add_trait_info(found_traits: &mut Vec<DefId>, trait_def_id: DefId, name: Name) {
+        fn add_trait_info(found_traits: &mut Vec<TraitCandidate>,
+                          trait_def_id: DefId,
+                          import_id: Option<NodeId>,
+                          name: Name) {
             debug!("(adding trait info) found trait {:?} for method '{}'",
                    trait_def_id,
                    name);
-            found_traits.push(trait_def_id);
+            found_traits.push(TraitCandidate {
+                def_id: trait_def_id,
+                import_id: import_id,
+            });
         }
 
         let mut found_traits = Vec::new();
         // Look for the current trait.
         if let Some((trait_def_id, _)) = self.current_trait_ref {
             if self.trait_item_map.contains_key(&(name, trait_def_id)) {
-                add_trait_info(&mut found_traits, trait_def_id, name);
+                add_trait_info(&mut found_traits, trait_def_id, None, name);
             }
         }
 
@@ -3147,8 +3156,14 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
                     let trait_def_id = binding.def().unwrap().def_id();
                     if self.trait_item_map.contains_key(&(name, trait_def_id)) {
-                        add_trait_info(&mut found_traits, trait_def_id, name);
-                        self.record_use(trait_name, TypeNS, binding);
+                        let mut import_id = None;
+                        if let NameBindingKind::Import { directive, .. } = binding.kind {
+                            let id = directive.id;
+                            self.maybe_unused_trait_imports.insert(id);
+                            import_id = Some(id);
+                        }
+                        add_trait_info(&mut found_traits, trait_def_id, import_id, name);
+                        self.record_use(trait_name, binding);
                     }
                 }
             };
@@ -3522,6 +3537,7 @@ fn err_path_resolution() -> PathResolution {
 pub struct CrateMap {
     pub def_map: RefCell<DefMap>,
     pub freevars: FreevarMap,
+    pub maybe_unused_trait_imports: NodeSet,
     pub export_map: ExportMap,
     pub trait_map: TraitMap,
     pub glob_map: Option<GlobMap>,
@@ -3559,6 +3575,7 @@ pub fn resolve_crate<'a, 'tcx>(session: &'a Session,
     CrateMap {
         def_map: resolver.def_map,
         freevars: resolver.freevars,
+        maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
         export_map: resolver.export_map,
         trait_map: resolver.trait_map,
         glob_map: if resolver.make_glob_map {
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index f0639a8517686..e37dd4cbc6eda 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.rs
@@ -25,7 +25,6 @@ use rustc::lint;
 use rustc::hir::def::*;
 
 use syntax::ast::{NodeId, Name};
-use syntax::attr::AttrMetaMethods;
 use syntax::codemap::{Span, DUMMY_SP};
 use syntax::util::lev_distance::find_best_match_for_name;
 
diff --git a/src/librustc_save_analysis/data.rs b/src/librustc_save_analysis/data.rs
index b79c459920a3e..e654cef0c3056 100644
--- a/src/librustc_save_analysis/data.rs
+++ b/src/librustc_save_analysis/data.rs
@@ -13,8 +13,6 @@
 //! The `Dump` trait can be used together with `DumpVisitor` in order to
 //! retrieve the data from a crate.
 
-use std::hash::Hasher;
-
 use rustc::hir::def_id::DefId;
 use rustc::ty;
 use syntax::ast::{CrateNum, NodeId};
diff --git a/src/librustc_trans/back/archive.rs b/src/librustc_trans/back/archive.rs
index 514fc52d0085b..aea61da18a0a1 100644
--- a/src/librustc_trans/back/archive.rs
+++ b/src/librustc_trans/back/archive.rs
@@ -21,8 +21,6 @@ use std::process::{Command, Output, Stdio};
 use std::ptr;
 use std::str;
 
-use middle::cstore::CrateStore;
-
 use libc;
 use llvm::archive_ro::{ArchiveRO, Child};
 use llvm::{self, ArchiveKind};
diff --git a/src/librustc_trans/back/link.rs b/src/librustc_trans/back/link.rs
index 4e77b2bc06940..3e69bb204b92d 100644
--- a/src/librustc_trans/back/link.rs
+++ b/src/librustc_trans/back/link.rs
@@ -19,7 +19,7 @@ use session::config::{OutputFilenames, Input, OutputType};
 use session::filesearch;
 use session::search_paths::PathKind;
 use session::Session;
-use middle::cstore::{self, CrateStore, LinkMeta};
+use middle::cstore::{self, LinkMeta};
 use middle::cstore::{LinkagePreference, NativeLibraryKind};
 use middle::dependency_format::Linkage;
 use CrateTranslation;
diff --git a/src/librustc_trans/back/linker.rs b/src/librustc_trans/back/linker.rs
index c02a482f81275..8055e97034e3f 100644
--- a/src/librustc_trans/back/linker.rs
+++ b/src/librustc_trans/back/linker.rs
@@ -16,7 +16,6 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 
 use back::archive;
-use middle::cstore::CrateStore;
 use middle::dependency_format::Linkage;
 use session::Session;
 use session::config::CrateTypeDylib;
diff --git a/src/librustc_trans/base.rs b/src/librustc_trans/base.rs
index b100282781ece..dd453bf996916 100644
--- a/src/librustc_trans/base.rs
+++ b/src/librustc_trans/base.rs
@@ -35,7 +35,6 @@ use lint;
 use llvm::{BasicBlockRef, Linkage, ValueRef, Vector, get_param};
 use llvm;
 use rustc::cfg;
-use middle::cstore::CrateStore;
 use rustc::hir::def_id::DefId;
 use rustc::infer;
 use middle::lang_items::{LangItem, ExchangeMallocFnLangItem, StartFnLangItem};
diff --git a/src/librustc_trans/common.rs b/src/librustc_trans/common.rs
index 5ce7caf5deb06..70348cf35e5f5 100644
--- a/src/librustc_trans/common.rs
+++ b/src/librustc_trans/common.rs
@@ -39,7 +39,7 @@ use type_::Type;
 use value::Value;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::traits::{self, SelectionContext, ProjectionMode};
-use rustc::ty::fold::{TypeFolder, TypeFoldable};
+use rustc::ty::fold::TypeFoldable;
 use rustc::hir;
 use util::nodemap::NodeMap;
 
diff --git a/src/librustc_trans/inline.rs b/src/librustc_trans/inline.rs
index 1eff09d67f96b..af175fbf88256 100644
--- a/src/librustc_trans/inline.rs
+++ b/src/librustc_trans/inline.rs
@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use llvm::{AvailableExternallyLinkage, InternalLinkage, SetLinkage};
-use middle::cstore::{CrateStore, FoundAst, InlinedItem};
+use middle::cstore::{FoundAst, InlinedItem};
 use rustc::hir::def_id::DefId;
 use rustc::ty::subst::Substs;
 use base::{push_ctxt, trans_item, trans_fn};
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index 6c8d437f429f9..b30277d745eb4 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -71,7 +71,7 @@ use rustc::ty::adjustment::{AdjustUnsafeFnPointer, AdjustMutToConstPointer};
 use rustc::ty::{self, LvaluePreference, TypeAndMut, Ty, TyCtxt};
 use rustc::ty::fold::TypeFoldable;
 use rustc::ty::error::TypeError;
-use rustc::ty::relate::{RelateResult, TypeRelation};
+use rustc::ty::relate::RelateResult;
 use util::common::indent;
 
 use std::cell::RefCell;
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index b71ee8722ab60..29a9ae9e5162d 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -11,18 +11,15 @@
 //! Type-checking for the rust-intrinsic and platform-intrinsic
 //! intrinsics that the compiler exposes.
 
-use astconv::AstConv;
 use intrinsics;
 use rustc::ty::subst::{self, Substs};
 use rustc::ty::FnSig;
 use rustc::ty::{self, Ty, TyCtxt};
-use rustc::ty::fold::TypeFolder;
 use {CrateCtxt, require_same_types};
 
 use std::collections::{HashMap};
 use syntax::abi::Abi;
 use syntax::ast;
-use syntax::attr::AttrMetaMethods;
 use syntax::codemap::Span;
 use syntax::parse::token;
 
diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index 31d95af4fbb9c..26d1f50f8c549 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -10,7 +10,6 @@
 
 //! Method lookup: the secret sauce of Rust. See `README.md`.
 
-use astconv::AstConv;
 use check::FnCtxt;
 use hir::def::Def;
 use hir::def_id::DefId;
@@ -129,6 +128,11 @@ pub fn lookup<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
     let mode = probe::Mode::MethodCall;
     let self_ty = fcx.infcx().resolve_type_vars_if_possible(&self_ty);
     let pick = probe::probe(fcx, span, mode, method_name, self_ty, call_expr.id)?;
+
+    if let Some(import_id) = pick.import_id {
+        fcx.tcx().used_trait_imports.borrow_mut().insert(import_id);
+    }
+
     Ok(confirm::confirm(fcx, span, self_expr, call_expr, self_ty, pick, supplied_method_types))
 }
 
@@ -340,8 +344,12 @@ pub fn resolve_ufcs<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
 {
     let mode = probe::Mode::Path;
     let pick = probe::probe(fcx, span, mode, method_name, self_ty, expr_id)?;
-    let def = pick.item.def();
 
+    if let Some(import_id) = pick.import_id {
+        fcx.tcx().used_trait_imports.borrow_mut().insert(import_id);
+    }
+
+    let def = pick.item.def();
     if let probe::InherentImplPick = pick.kind {
         if !pick.item.vis().is_accessible_from(fcx.body_id, &fcx.tcx().map) {
             let msg = format!("{} `{}` is private", def.kind_name(), &method_name.as_str());
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 8a71debdf206b..0e064fbc45baa 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -42,6 +42,7 @@ struct ProbeContext<'a, 'tcx:'a> {
     inherent_candidates: Vec<Candidate<'tcx>>,
     extension_candidates: Vec<Candidate<'tcx>>,
     impl_dups: HashSet<DefId>,
+    import_id: Option<ast::NodeId>,
 
     /// Collects near misses when the candidate functions are missing a `self` keyword and is only
     /// used for error reporting
@@ -67,6 +68,7 @@ struct Candidate<'tcx> {
     xform_self_ty: Ty<'tcx>,
     item: ty::ImplOrTraitItem<'tcx>,
     kind: CandidateKind<'tcx>,
+    import_id: Option<ast::NodeId>,
 }
 
 #[derive(Debug)]
@@ -84,6 +86,7 @@ enum CandidateKind<'tcx> {
 pub struct Pick<'tcx> {
     pub item: ty::ImplOrTraitItem<'tcx>,
     pub kind: PickKind<'tcx>,
+    pub import_id: Option<ast::NodeId>,
 
     // Indicates that the source expression should be autoderef'd N times
     //
@@ -247,6 +250,7 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             inherent_candidates: Vec::new(),
             extension_candidates: Vec::new(),
             impl_dups: HashSet::new(),
+            import_id: None,
             steps: Rc::new(steps),
             opt_simplified_steps: opt_simplified_steps,
             static_candidates: Vec::new(),
@@ -435,7 +439,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
         self.inherent_candidates.push(Candidate {
             xform_self_ty: xform_self_ty,
             item: item,
-            kind: InherentImplCandidate(impl_substs, obligations)
+            kind: InherentImplCandidate(impl_substs, obligations),
+            import_id: self.import_id,
         });
     }
 
@@ -463,7 +468,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             this.inherent_candidates.push(Candidate {
                 xform_self_ty: xform_self_ty,
                 item: item,
-                kind: ObjectCandidate
+                kind: ObjectCandidate,
+                import_id: this.import_id,
             });
         });
     }
@@ -534,7 +540,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             this.inherent_candidates.push(Candidate {
                 xform_self_ty: xform_self_ty,
                 item: item,
-                kind: WhereClauseCandidate(poly_trait_ref)
+                kind: WhereClauseCandidate(poly_trait_ref),
+                import_id: this.import_id,
             });
         });
     }
@@ -578,9 +585,13 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
         let mut duplicates = HashSet::new();
         let opt_applicable_traits = self.fcx.ccx.trait_map.get(&expr_id);
         if let Some(applicable_traits) = opt_applicable_traits {
-            for &trait_did in applicable_traits {
+            for trait_candidate in applicable_traits {
+                let trait_did = trait_candidate.def_id;
                 if duplicates.insert(trait_did) {
-                    self.assemble_extension_candidates_for_trait(trait_did)?;
+                    self.import_id = trait_candidate.import_id;
+                    let result = self.assemble_extension_candidates_for_trait(trait_did);
+                    self.import_id = None;
+                    result?;
                 }
             }
         }
@@ -680,7 +691,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             self.extension_candidates.push(Candidate {
                 xform_self_ty: xform_self_ty,
                 item: item.clone(),
-                kind: ExtensionImplCandidate(impl_def_id, impl_substs, obligations)
+                kind: ExtensionImplCandidate(impl_def_id, impl_substs, obligations),
+                import_id: self.import_id,
             });
         });
     }
@@ -755,7 +767,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             self.inherent_candidates.push(Candidate {
                 xform_self_ty: xform_self_ty,
                 item: item.clone(),
-                kind: TraitCandidate
+                kind: TraitCandidate,
+                import_id: self.import_id,
             });
         }
 
@@ -812,7 +825,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
                     self.extension_candidates.push(Candidate {
                         xform_self_ty: xform_self_ty,
                         item: item.clone(),
-                        kind: TraitCandidate
+                        kind: TraitCandidate,
+                        import_id: self.import_id,
                     });
                 }
             }
@@ -843,7 +857,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             self.extension_candidates.push(Candidate {
                 xform_self_ty: xform_self_ty,
                 item: item.clone(),
-                kind: WhereClauseCandidate(poly_bound)
+                kind: WhereClauseCandidate(poly_bound),
+                import_id: self.import_id,
             });
         }
     }
@@ -1141,6 +1156,7 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
         Some(Pick {
             item: probes[0].item.clone(),
             kind: TraitPick,
+            import_id: probes[0].import_id,
             autoderefs: 0,
             autoref: None,
             unsize: None
@@ -1346,6 +1362,7 @@ impl<'tcx> Candidate<'tcx> {
                     WhereClausePick(trait_ref.clone())
                 }
             },
+            import_id: self.import_id,
             autoderefs: 0,
             autoref: None,
             unsize: None
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index fab3bb60e0b2a..6b90dcd54bf0f 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -13,11 +13,10 @@
 
 use CrateCtxt;
 
-use astconv::AstConv;
 use check::{self, FnCtxt, UnresolvedTypeAction, autoderef};
 use rustc::hir::map as hir_map;
 use rustc::ty::{self, Ty, ToPolyTraitRef, ToPredicate, TypeFoldable};
-use middle::cstore::{self, CrateStore};
+use middle::cstore;
 use hir::def::Def;
 use hir::def_id::DefId;
 use middle::lang_items::FnOnceTraitLangItem;
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 6599199c239af..10789228b97fe 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -99,8 +99,7 @@ use rustc::ty::{self, ToPolyTraitRef, Ty, TyCtxt, Visibility};
 use rustc::ty::{MethodCall, MethodCallee};
 use rustc::ty::adjustment;
 use rustc::ty::error::TypeError;
-use rustc::ty::fold::{TypeFolder, TypeFoldable};
-use rustc::ty::relate::TypeRelation;
+use rustc::ty::fold::TypeFoldable;
 use rustc::ty::util::{Representability, IntTypeExt};
 use require_c_abi_if_variadic;
 use rscope::{ElisionFailureInfo, RegionScope};
diff --git a/src/librustc_typeck/check/regionck.rs b/src/librustc_typeck/check/regionck.rs
index 5efd57c4d1fc9..bda4c42288020 100644
--- a/src/librustc_typeck/check/regionck.rs
+++ b/src/librustc_typeck/check/regionck.rs
@@ -82,7 +82,6 @@
 //! relation, except that a borrowed pointer never owns its
 //! contents.
 
-use astconv::AstConv;
 use check::dropck;
 use check::FnCtxt;
 use middle::free_region::FreeRegionMap;
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 25a37b6810e44..ffdae2339705e 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use astconv::AstConv;
 use check::{FnCtxt, Inherited, blank_fn_ctxt, regionck};
 use constrained_type_params::{identify_constrained_type_params, Parameter};
 use CrateCtxt;
@@ -17,7 +16,6 @@ use middle::region::{CodeExtent};
 use rustc::ty::subst::{self, TypeSpace, FnSpace, ParamSpace, SelfSpace};
 use rustc::traits;
 use rustc::ty::{self, Ty, TyCtxt};
-use rustc::ty::fold::{TypeFolder};
 
 use std::cell::RefCell;
 use std::collections::HashSet;
diff --git a/src/librustc_typeck/check/writeback.rs b/src/librustc_typeck/check/writeback.rs
index ad78740921cbc..4341ae5dac1cf 100644
--- a/src/librustc_typeck/check/writeback.rs
+++ b/src/librustc_typeck/check/writeback.rs
@@ -13,7 +13,6 @@
 // substitutions.
 use self::ResolveReason::*;
 
-use astconv::AstConv;
 use check::FnCtxt;
 use hir::def_id::DefId;
 use hir::pat_util;
diff --git a/src/librustc_typeck/check_unused.rs b/src/librustc_typeck/check_unused.rs
new file mode 100644
index 0000000000000..3c594ebdf0bfc
--- /dev/null
+++ b/src/librustc_typeck/check_unused.rs
@@ -0,0 +1,64 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use lint;
+use rustc::dep_graph::DepNode;
+use rustc::ty::TyCtxt;
+
+use syntax::ast;
+use syntax::codemap::{Span, DUMMY_SP};
+
+use rustc::hir;
+use rustc::hir::intravisit::Visitor;
+
+struct UnusedTraitImportVisitor<'a, 'tcx: 'a> {
+    tcx: &'a TyCtxt<'tcx>,
+}
+
+impl<'a, 'tcx> UnusedTraitImportVisitor<'a, 'tcx> {
+    fn check_import(&self, id: ast::NodeId, span: Span) {
+        if !self.tcx.maybe_unused_trait_imports.contains(&id) {
+            return;
+        }
+        if self.tcx.used_trait_imports.borrow().contains(&id) {
+            return;
+        }
+        self.tcx.sess.add_lint(lint::builtin::UNUSED_IMPORTS,
+                               id,
+                               span,
+                               "unused import".to_string());
+    }
+}
+
+impl<'a, 'tcx, 'v> Visitor<'v> for UnusedTraitImportVisitor<'a, 'tcx> {
+    fn visit_item(&mut self, item: &hir::Item) {
+        if item.vis == hir::Public || item.span == DUMMY_SP {
+            return;
+        }
+        if let hir::ItemUse(ref path) = item.node {
+            match path.node {
+                hir::ViewPathSimple(..) | hir::ViewPathGlob(..) => {
+                    self.check_import(item.id, path.span);
+                }
+                hir::ViewPathList(_, ref path_list) => {
+                    for path_item in path_list {
+                        self.check_import(path_item.node.id(), path_item.span);
+                    }
+                }
+            }
+        }
+    }
+}
+
+pub fn check_crate(tcx: &TyCtxt) {
+    let _task = tcx.dep_graph.in_task(DepNode::UnusedTraitCheck);
+    let mut visitor = UnusedTraitImportVisitor { tcx: tcx };
+    tcx.map.krate().visit_all_items(&mut visitor);
+}
diff --git a/src/librustc_typeck/coherence/overlap.rs b/src/librustc_typeck/coherence/overlap.rs
index a05167dbe4333..30d181abb9e9d 100644
--- a/src/librustc_typeck/coherence/overlap.rs
+++ b/src/librustc_typeck/coherence/overlap.rs
@@ -12,7 +12,6 @@
 //! same type. Likewise, no two inherent impls for a given type
 //! constructor provide a method with the same name.
 
-use middle::cstore::CrateStore;
 use hir::def_id::DefId;
 use rustc::traits::{self, ProjectionMode};
 use rustc::infer;
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 4dd093e2e4bfd..19807ab840b3a 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -73,7 +73,6 @@ use rustc::ty::subst::{Substs, FnSpace, ParamSpace, SelfSpace, TypeSpace, VecPer
 use rustc::ty::{ToPredicate, ImplContainer, ImplOrTraitItemContainer, TraitContainer};
 use rustc::ty::{self, ToPolyTraitRef, Ty, TyCtxt, TypeScheme};
 use rustc::ty::{VariantKind};
-use rustc::ty::fold::{TypeFolder};
 use rustc::ty::util::IntTypeExt;
 use rscope::*;
 use rustc::dep_graph::DepNode;
diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index c51304120a89c..ed393b54f0e27 100644
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -122,6 +122,7 @@ use std::cell::RefCell;
 pub mod diagnostics;
 
 pub mod check;
+pub mod check_unused;
 mod rscope;
 mod astconv;
 pub mod collect;
@@ -363,6 +364,7 @@ pub fn check_crate(tcx: &TyCtxt, trait_map: hir::TraitMap) -> CompileResult {
 
     time(time_passes, "drop-impl checking", || check::check_drop_impls(&ccx))?;
 
+    check_unused::check_crate(tcx);
     check_for_entry_fn(&ccx);
 
     let err_count = tcx.sess.err_count();
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 36eb1a1301c9d..742afdc5e98e5 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -14,10 +14,9 @@ use std::collections::HashSet;
 use std::iter::once;
 
 use syntax::ast;
-use syntax::attr::AttrMetaMethods;
 use rustc::hir;
 
-use rustc::middle::cstore::{self, CrateStore};
+use rustc::middle::cstore;
 use rustc::hir::def::Def;
 use rustc::hir::def_id::DefId;
 use rustc::hir::print as pprust;
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 398781e14052f..f5b8db1143ed6 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -35,7 +35,7 @@ use syntax::parse::token::{self, InternedString, keywords};
 use syntax::ptr::P;
 
 use rustc_trans::back::link;
-use rustc::middle::cstore::{self, CrateStore};
+use rustc::middle::cstore;
 use rustc::middle::privacy::AccessLevels;
 use rustc::hir::def::Def;
 use rustc::hir::def_id::{DefId, DefIndex, CRATE_DEF_INDEX};
diff --git a/src/librustdoc/html/layout.rs b/src/librustdoc/html/layout.rs
index 8b2e84974985c..a168fe98a94cf 100644
--- a/src/librustdoc/html/layout.rs
+++ b/src/librustdoc/html/layout.rs
@@ -9,7 +9,6 @@
 // except according to those terms.
 
 use std::fmt;
-use std::io::prelude::*;
 use std::io;
 
 use externalfiles::ExternalHtml;
diff --git a/src/libstd/collections/hash/bench.rs b/src/libstd/collections/hash/bench.rs
index 9fae9af2d54d4..a1275d23d5710 100644
--- a/src/libstd/collections/hash/bench.rs
+++ b/src/libstd/collections/hash/bench.rs
@@ -11,7 +11,6 @@
 #![cfg(test)]
 
 extern crate test;
-use prelude::v1::*;
 
 use self::test::Bencher;
 
diff --git a/src/libstd/io/error.rs b/src/libstd/io/error.rs
index 9a605fc7bbff4..e142c78569bd7 100644
--- a/src/libstd/io/error.rs
+++ b/src/libstd/io/error.rs
@@ -350,7 +350,6 @@ mod test {
     use prelude::v1::*;
     use super::{Error, ErrorKind};
     use error;
-    use error::Error as error_Error;
     use fmt;
     use sys::os::error_string;
 
diff --git a/src/libstd/sys/windows/fs.rs b/src/libstd/sys/windows/fs.rs
index 529e42248f6a2..3cd45afaf0148 100644
--- a/src/libstd/sys/windows/fs.rs
+++ b/src/libstd/sys/windows/fs.rs
@@ -9,7 +9,6 @@
 // except according to those terms.
 
 use prelude::v1::*;
-use io::prelude::*;
 use os::windows::prelude::*;
 
 use ffi::OsString;
diff --git a/src/libsyntax/errors/emitter.rs b/src/libsyntax/errors/emitter.rs
index 486e2ace0876a..e7007fb05688b 100644
--- a/src/libsyntax/errors/emitter.rs
+++ b/src/libsyntax/errors/emitter.rs
@@ -10,7 +10,7 @@
 
 use self::Destination::*;
 
-use codemap::{self, COMMAND_LINE_SP, DUMMY_SP, Pos, Span, MultiSpan};
+use codemap::{self, COMMAND_LINE_SP, DUMMY_SP, Span, MultiSpan};
 use diagnostics;
 
 use errors::check_old_skool;
diff --git a/src/libsyntax_ext/deriving/clone.rs b/src/libsyntax_ext/deriving/clone.rs
index c81198d4729fb..2c21fd2cd5ed2 100644
--- a/src/libsyntax_ext/deriving/clone.rs
+++ b/src/libsyntax_ext/deriving/clone.rs
@@ -12,7 +12,7 @@ use deriving::generic::*;
 use deriving::generic::ty::*;
 
 use syntax::ast::{Expr, ItemKind, Generics, MetaItem, VariantData};
-use syntax::attr::{self, AttrMetaMethods};
+use syntax::attr;
 use syntax::codemap::Span;
 use syntax::ext::base::{ExtCtxt, Annotatable};
 use syntax::ext::build::AstBuilder;
diff --git a/src/test/compile-fail/dep-graph-trait-impl-two-traits-same-method.rs b/src/test/compile-fail/dep-graph-trait-impl-two-traits-same-method.rs
index 1afecd80ff5ad..5e4f43af669ca 100644
--- a/src/test/compile-fail/dep-graph-trait-impl-two-traits-same-method.rs
+++ b/src/test/compile-fail/dep-graph-trait-impl-two-traits-same-method.rs
@@ -15,6 +15,7 @@
 
 #![feature(rustc_attrs)]
 #![allow(dead_code)]
+#![allow(unused_imports)]
 
 fn main() { }
 
diff --git a/src/test/compile-fail/lint-unused-imports.rs b/src/test/compile-fail/lint-unused-imports.rs
index 3c1f4b0430621..40322f5a5b53b 100644
--- a/src/test/compile-fail/lint-unused-imports.rs
+++ b/src/test/compile-fail/lint-unused-imports.rs
@@ -24,6 +24,8 @@ use test::A;       //~ ERROR unused import
 // Be sure that if we just bring some methods into scope that they're also
 // counted as being used.
 use test::B;
+// But only when actually used: do not get confused by the method with the same name.
+use test::B2; //~ ERROR unused import
 
 // Make sure this import is warned about when at least one of its imported names
 // is unused
@@ -37,6 +39,7 @@ mod test2 {
 mod test {
     pub trait A { fn a(&self) {} }
     pub trait B { fn b(&self) {} }
+    pub trait B2 { fn b(&self) {} }
     pub struct C;
     impl A for C {}
     impl B for C {}
diff --git a/src/tools/cargotest/main.rs b/src/tools/cargotest/main.rs
index 7ad54c5bf6be4..7e688b5ec6b46 100644
--- a/src/tools/cargotest/main.rs
+++ b/src/tools/cargotest/main.rs
@@ -25,7 +25,7 @@ const TEST_REPOS: &'static [Test] = &[
     Test {
         name: "cargo",
         repo: "https://github.com/rust-lang/cargo",
-        sha: "fae9c539388f1b7c70c31fd0a21b5dd9cd071177",
+        sha: "26288f799427f9cc6e8bdddd782a17a8156ebc64",
         lock: None,
     },
     Test {
diff --git a/src/tools/rustbook/main.rs b/src/tools/rustbook/main.rs
index 5ad4982e8af6e..e0092f8e29e73 100644
--- a/src/tools/rustbook/main.rs
+++ b/src/tools/rustbook/main.rs
@@ -19,10 +19,8 @@ extern crate rustdoc;
 extern crate rustc_back;
 
 use std::env;
-use std::error::Error;
 use std::process;
 use std::sync::atomic::{AtomicIsize, ATOMIC_ISIZE_INIT, Ordering};
-use subcommand::Subcommand;
 use term::Term;
 
 mod term;