Remove unused trait imports flagged by lint

39 files changed, 13 insertions, 50 deletions

diff --git a/src/libcoretest/lib.rs b/src/libcoretest/lib.rs
index aa7ab4b4e3f..dc01a9b5c78 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 11c1bd667fb..d5a6e0f87d6 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/librustc_const_eval/eval.rs b/src/librustc_const_eval/eval.rs
index 132caa010d4..adce0f5d45a 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/lib.rs b/src/librustc_driver/lib.rs
index 4aaeeed3430..b31c7ab6678 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_incremental/persist/data.rs b/src/librustc_incremental/persist/data.rs
index 60d644ba768..37d5f8937f1 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 7f4c7d919c0..796812556d2 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 4bdd926869a..6a51b1a43ad 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 891731cb296..b81a4a0efe7 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 8e7be0e3a0f..6a79d5df80a 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 b5b27586a7f..58bc4e2a193 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 40a7f91154f..7558e0774b3 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 2316a67d9d3..4ecb7a28ef7 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 d55d0d53b8c..4a4b7caf478 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 4dc19434c80..f5e72195bc3 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/lib.rs b/src/librustc_resolve/lib.rs
index e747ed15260..9ef927b6610 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -47,7 +47,6 @@ 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;
@@ -58,7 +57,6 @@ use rustc::util::nodemap::{NodeMap, 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};
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index f0639a85176..e37dd4cbc6e 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 b79c459920a..e654cef0c30 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 514fc52d008..aea61da18a0 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 4e77b2bc069..3e69bb204b9 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 c02a482f812..8055e97034e 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 b100282781e..dd453bf9969 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 5ce7caf5deb..70348cf35e5 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 1eff09d67f9..af175fbf882 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 f1c6868efd2..711d695a6ef 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 b71ee8722ab..29a9ae9e516 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 31d95af4fbb..367cac68509 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;
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 4ba8f2c9d62..cf1b609884b 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 385f04b8564..14394d91e61 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 5efd57c4d1f..bda4c422880 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 25a37b6810e..ffdae233970 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 ad78740921c..4341ae5dac1 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/coherence/overlap.rs b/src/librustc_typeck/coherence/overlap.rs
index a05167dbe43..30d181abb9e 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 c10488a03ef..d88bfd95367 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/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index e13b2688788..68e4ed000b0 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::ty::{self, TyCtxt};
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 35922c477cc..caf02d73e47 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 8b2e8497498..a168fe98a94 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 9fae9af2d54..a1275d23d57 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 9a605fc7bbf..e142c78569b 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/tools/rustbook/main.rs b/src/tools/rustbook/main.rs
index 5ad4982e8af..e0092f8e29e 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;