Fix lint findings in librustc

src/librustc/infer/error_reporting/mod.rs

@@ -690,7 +690,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         name: String,
         sub: ty::subst::SubstsRef<'tcx>,
         pos: usize,
-        other_ty: &Ty<'tcx>,
+        other_ty: Ty<'tcx>,
     ) {
         // `value` and `other_value` hold two incomplete type representation for display.
         // `name` is the path of both types being compared. `sub`
@@ -768,10 +768,10 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         path: String,
         sub: ty::subst::SubstsRef<'tcx>,
         other_path: String,
-        other_ty: &Ty<'tcx>,
+        other_ty: Ty<'tcx>,
     ) -> Option<()> {
         for (i, ta) in sub.types().enumerate() {
-            if &ta == other_ty {
+            if ta == other_ty {
                 self.highlight_outer(&mut t1_out, &mut t2_out, path, sub, i, &other_ty);
                 return Some(());
             }
@@ -839,7 +839,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     /// Compares two given types, eliding parts that are the same between them and highlighting
     /// relevant differences, and return two representation of those types for highlighted printing.
     fn cmp(&self, t1: Ty<'tcx>, t2: Ty<'tcx>) -> (DiagnosticStyledString, DiagnosticStyledString) {
-        fn equals<'tcx>(a: &Ty<'tcx>, b: &Ty<'tcx>) -> bool {
+        fn equals<'tcx>(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
             match (&a.sty, &b.sty) {
                 (a, b) if *a == *b => true,
                 (&ty::Int(_), &ty::Infer(ty::InferTy::IntVar(_)))
@@ -1099,7 +1099,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             }
         };
 
-        let span = cause.span(&self.tcx);
+        let span = cause.span(self.tcx);
 
         diag.span_label(span, terr.to_string());
         if let Some((sp, msg)) = secondary_span {
@@ -1233,7 +1233,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             trace, terr
         );
 
-        let span = trace.cause.span(&self.tcx);
+        let span = trace.cause.span(self.tcx);
         let failure_code = trace.cause.as_failure_code(terr);
         let mut diag = match failure_code {
             FailureCode::Error0317(failure_str) => {

src/librustc/infer/error_reporting/need_type_info.rs

@@ -11,7 +11,7 @@ use errors::DiagnosticBuilder;
 
 struct FindLocalByTypeVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
-    target_ty: &'a Ty<'tcx>,
+    target_ty: Ty<'tcx>,
     hir_map: &'a hir::map::Map<'gcx>,
     found_local_pattern: Option<&'gcx Pat>,
     found_arg_pattern: Option<&'gcx Pat>,
@@ -26,7 +26,7 @@ impl<'a, 'gcx, 'tcx> FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
             Some(ty) => {
                 let ty = self.infcx.resolve_type_vars_if_possible(&ty);
                 ty.walk().any(|inner_ty| {
-                    inner_ty == *self.target_ty || match (&inner_ty.sty, &self.target_ty.sty) {
+                    inner_ty == self.target_ty || match (&inner_ty.sty, &self.target_ty.sty) {
                         (&Infer(TyVar(a_vid)), &Infer(TyVar(b_vid))) => {
                             self.infcx
                                 .type_variables
@@ -68,10 +68,10 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
 impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     pub fn extract_type_name(
         &self,
-        ty: &'a Ty<'tcx>,
+        ty: Ty<'tcx>,
         highlight: Option<ty::print::RegionHighlightMode>,
     ) -> String {
-        if let ty::Infer(ty::TyVar(ty_vid)) = (*ty).sty {
+        if let ty::Infer(ty::TyVar(ty_vid)) = ty.sty {
             let ty_vars = self.type_variables.borrow();
             if let TypeVariableOrigin::TypeParameterDefinition(_, name) =
                 *ty_vars.var_origin(ty_vid) {
@@ -102,7 +102,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
 
         let mut local_visitor = FindLocalByTypeVisitor {
             infcx: &self,
-            target_ty: &ty,
+            target_ty: ty,
             hir_map: &self.tcx.hir(),
             found_local_pattern: None,
             found_arg_pattern: None,

src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs

@@ -193,7 +193,7 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
         );
 
         let mut err = self.tcx().sess.struct_span_err(
-            cause.span(&self.tcx()),
+            cause.span(self.tcx()),
             &format!(
                 "implementation of `{}` is not general enough",
                 self.tcx().def_path_str(trait_def_id),

src/librustc/infer/nll_relate/mod.rs

@@ -267,7 +267,7 @@ where
     fn relate_projection_ty(
         &mut self,
         projection_ty: ty::ProjectionTy<'tcx>,
-        value_ty: ty::Ty<'tcx>,
+        value_ty: Ty<'tcx>,
     ) -> Ty<'tcx> {
         use crate::infer::type_variable::TypeVariableOrigin;
         use crate::traits::WhereClause;

src/librustc/middle/exported_symbols.rs

@@ -4,7 +4,7 @@ use rustc_data_structures::stable_hasher::{StableHasher, HashStable,
                                            StableHasherResult};
 use std::cmp;
 use std::mem;
-use crate::ty;
+use crate::ty::{self, TyCtxt};
 use crate::ty::subst::SubstsRef;
 
 /// The SymbolExportLevel of a symbols specifies from which kinds of crates
@@ -39,7 +39,7 @@ pub enum ExportedSymbol<'tcx> {
 
 impl<'tcx> ExportedSymbol<'tcx> {
     pub fn symbol_name(&self,
-                       tcx: ty::TyCtxt<'_, 'tcx, '_>)
+                       tcx: TyCtxt<'_, 'tcx, '_>)
                        -> ty::SymbolName {
         match *self {
             ExportedSymbol::NonGeneric(def_id) => {
@@ -55,7 +55,7 @@ impl<'tcx> ExportedSymbol<'tcx> {
     }
 
     pub fn compare_stable(&self,
-                          tcx: ty::TyCtxt<'_, 'tcx, '_>,
+                          tcx: TyCtxt<'_, 'tcx, '_>,
                           other: &ExportedSymbol<'tcx>)
                           -> cmp::Ordering {
         match *self {
@@ -92,7 +92,7 @@ impl<'tcx> ExportedSymbol<'tcx> {
     }
 }
 
-pub fn metadata_symbol_name(tcx: ty::TyCtxt<'_, '_, '_>) -> String {
+pub fn metadata_symbol_name(tcx: TyCtxt<'_, '_, '_>) -> String {
     format!("rust_metadata_{}_{}",
             tcx.original_crate_name(LOCAL_CRATE),
             tcx.crate_disambiguator(LOCAL_CRATE).to_fingerprint().to_hex())

src/librustc/mir/mono.rs

@@ -18,7 +18,7 @@ pub enum MonoItem<'tcx> {
 }
 
 impl<'tcx> MonoItem<'tcx> {
-    pub fn size_estimate<'a>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> usize {
+    pub fn size_estimate<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> usize {
         match *self {
             MonoItem::Fn(instance) => {
                 // Estimate the size of a function based on how many statements
@@ -144,7 +144,7 @@ impl<'tcx> CodegenUnit<'tcx> {
         base_n::encode(hash, base_n::CASE_INSENSITIVE)
     }
 
-    pub fn estimate_size<'a>(&mut self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) {
+    pub fn estimate_size<'a>(&mut self, tcx: TyCtxt<'a, 'tcx, 'tcx>) {
         // Estimate the size of a codegen unit as (approximately) the number of MIR
         // statements it corresponds to.
         self.size_estimate = Some(self.items.keys().map(|mi| mi.size_estimate(tcx)).sum());

src/librustc/mir/visit.rs

@@ -198,7 +198,7 @@ macro_rules! make_mir_visitor {
             }
 
             fn visit_ty(&mut self,
-                        ty: & $($mutability)? Ty<'tcx>,
+                        ty: $(& $mutability)? Ty<'tcx>,
                         _: TyContext) {
                 self.super_ty(ty);
             }
@@ -864,7 +864,7 @@ macro_rules! make_mir_visitor {
                 self.visit_ty(& $($mutability)? ty.inferred_ty, TyContext::UserTy(ty.span));
             }
 
-            fn super_ty(&mut self, _ty: & $($mutability)? Ty<'tcx>) {
+            fn super_ty(&mut self, _ty: $(& $mutability)? Ty<'tcx>) {
             }
 
             fn super_region(&mut self, _region: & $($mutability)? ty::Region<'tcx>) {

src/librustc/traits/auto_trait.rs

@@ -49,11 +49,11 @@ pub struct AutoTraitInfo<'cx> {
 }
 
 pub struct AutoTraitFinder<'a, 'tcx: 'a> {
-    tcx: &'a TyCtxt<'a, 'tcx, 'tcx>,
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
 }
 
 impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
-    pub fn new(tcx: &'a TyCtxt<'a, 'tcx, 'tcx>) -> Self {
+    pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Self {
         AutoTraitFinder { tcx }
     }
 
@@ -291,7 +291,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
         infcx: &InferCtxt<'b, 'tcx, 'c>,
         ty_did: DefId,
         trait_did: DefId,
-        ty: ty::Ty<'c>,
+        ty: Ty<'c>,
         param_env: ty::ParamEnv<'c>,
         user_env: ty::ParamEnv<'c>,
         fresh_preds: &mut FxHashSet<ty::Predicate<'c>>,
@@ -661,7 +661,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
         T: Iterator<Item = Obligation<'cx, ty::Predicate<'cx>>>,
     >(
         &self,
-        ty: ty::Ty<'_>,
+        ty: Ty<'_>,
         nested: T,
         computed_preds: &'b mut FxHashSet<ty::Predicate<'cx>>,
         fresh_preds: &'b mut FxHashSet<ty::Predicate<'cx>>,

src/librustc/traits/error_reporting.rs

@@ -1242,7 +1242,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                            found: ty::PolyTraitRef<'tcx>)
         -> DiagnosticBuilder<'tcx>
     {
-        fn build_fn_sig_string<'a, 'gcx, 'tcx>(tcx: ty::TyCtxt<'a, 'gcx, 'tcx>,
+        fn build_fn_sig_string<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                                                trait_ref: &ty::TraitRef<'tcx>) -> String {
             let inputs = trait_ref.substs.type_at(1);
             let sig = if let ty::Tuple(inputs) = inputs.sty {

src/librustc/traits/mod.rs

@@ -138,7 +138,7 @@ pub struct ObligationCause<'tcx> {
 }
 
 impl<'tcx> ObligationCause<'tcx> {
-    pub fn span<'a, 'gcx>(&self, tcx: &TyCtxt<'a, 'gcx, 'tcx>) -> Span {
+    pub fn span<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Span {
         match self.code {
             ObligationCauseCode::CompareImplMethodObligation { .. } |
             ObligationCauseCode::MainFunctionType |

src/librustc/traits/structural_impls.rs

@@ -3,7 +3,7 @@ use smallvec::SmallVec;
 use crate::traits;
 use crate::traits::project::Normalized;
 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
-use crate::ty::{self, Lift, TyCtxt};
+use crate::ty::{self, Lift, Ty, TyCtxt};
 use syntax::symbol::InternedString;
 
 use std::fmt;
@@ -311,7 +311,7 @@ impl<'tcx> TypeVisitor<'tcx> for BoundNamesCollector {
         result
     }
 
-    fn visit_ty(&mut self, t: ty::Ty<'tcx>) -> bool {
+    fn visit_ty(&mut self, t: Ty<'tcx>) -> bool {
         use syntax::symbol::Symbol;
 
         match t.sty {

src/librustc/ty/fold.rs

@@ -421,7 +421,7 @@ struct BoundVarReplacer<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     current_index: ty::DebruijnIndex,
 
     fld_r: &'a mut (dyn FnMut(ty::BoundRegion) -> ty::Region<'tcx> + 'a),
-    fld_t: &'a mut (dyn FnMut(ty::BoundTy) -> ty::Ty<'tcx> + 'a),
+    fld_t: &'a mut (dyn FnMut(ty::BoundTy) -> Ty<'tcx> + 'a),
 }
 
 impl<'a, 'gcx, 'tcx> BoundVarReplacer<'a, 'gcx, 'tcx> {
@@ -431,7 +431,7 @@ impl<'a, 'gcx, 'tcx> BoundVarReplacer<'a, 'gcx, 'tcx> {
         fld_t: &'a mut G
     ) -> Self
         where F: FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
-              G: FnMut(ty::BoundTy) -> ty::Ty<'tcx>
+              G: FnMut(ty::BoundTy) -> Ty<'tcx>
     {
         BoundVarReplacer {
             tcx,
@@ -533,7 +533,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         mut fld_t: G
     ) -> (T, BTreeMap<ty::BoundRegion, ty::Region<'tcx>>)
         where F: FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
-              G: FnMut(ty::BoundTy) -> ty::Ty<'tcx>,
+              G: FnMut(ty::BoundTy) -> Ty<'tcx>,
               T: TypeFoldable<'tcx>
     {
         use rustc_data_structures::fx::FxHashMap;
@@ -568,7 +568,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         fld_t: G
     ) -> (T, BTreeMap<ty::BoundRegion, ty::Region<'tcx>>)
         where F: FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
-              G: FnMut(ty::BoundTy) -> ty::Ty<'tcx>,
+              G: FnMut(ty::BoundTy) -> Ty<'tcx>,
               T: TypeFoldable<'tcx>
     {
         self.replace_escaping_bound_vars(value.skip_binder(), fld_r, fld_t)
@@ -710,7 +710,7 @@ impl TypeFolder<'gcx, 'tcx> for Shifter<'a, 'gcx, 'tcx> {
         }
     }
 
-    fn fold_ty(&mut self, ty: ty::Ty<'tcx>) -> ty::Ty<'tcx> {
+    fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
         match ty.sty {
             ty::Bound(debruijn, bound_ty) => {
                 if self.amount == 0 || debruijn < self.current_index {

src/librustc/ty/mod.rs

@@ -212,7 +212,7 @@ impl AssociatedItem {
         }
     }
 
-    pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
+    pub fn signature<'a, 'tcx>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String {
         match self.kind {
             ty::AssociatedKind::Method => {
                 // We skip the binder here because the binder would deanonymize all

src/librustc/ty/query/on_disk_cache.rs

@@ -9,7 +9,7 @@ use crate::rustc_serialize::{Decodable, Decoder, Encodable, Encoder, opaque,
                       SpecializedDecoder, SpecializedEncoder,
                       UseSpecializedDecodable, UseSpecializedEncodable};
 use crate::session::{CrateDisambiguator, Session};
-use crate::ty;
+use crate::ty::{self, Ty};
 use crate::ty::codec::{self as ty_codec, TyDecoder, TyEncoder};
 use crate::ty::context::TyCtxt;
 use crate::util::common::{time, time_ext};
@@ -545,8 +545,8 @@ impl<'a, 'tcx: 'a, 'x> ty_codec::TyDecoder<'a, 'tcx> for CacheDecoder<'a, 'tcx,
     fn cached_ty_for_shorthand<F>(&mut self,
                                   shorthand: usize,
                                   or_insert_with: F)
-                                  -> Result<ty::Ty<'tcx>, Self::Error>
+                                  -> Result<Ty<'tcx>, Self::Error>
-        where F: FnOnce(&mut Self) -> Result<ty::Ty<'tcx>, Self::Error>
+        where F: FnOnce(&mut Self) -> Result<Ty<'tcx>, Self::Error>
     {
         let tcx = self.tcx();
 
@@ -751,7 +751,7 @@ struct CacheEncoder<'enc, 'a, 'tcx, E>
 {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     encoder: &'enc mut E,
-    type_shorthands: FxHashMap<ty::Ty<'tcx>, usize>,
+    type_shorthands: FxHashMap<Ty<'tcx>, usize>,
     predicate_shorthands: FxHashMap<ty::Predicate<'tcx>, usize>,
     expn_info_shorthands: FxHashMap<Mark, AbsoluteBytePos>,
     interpret_allocs: FxHashMap<interpret::AllocId, usize>,
@@ -881,11 +881,11 @@ impl<'enc, 'a, 'tcx, E> SpecializedEncoder<CrateNum> for CacheEncoder<'enc, 'a,
     }
 }
 
-impl<'enc, 'a, 'tcx, E> SpecializedEncoder<ty::Ty<'tcx>> for CacheEncoder<'enc, 'a, 'tcx, E>
+impl<'enc, 'a, 'tcx, E> SpecializedEncoder<Ty<'tcx>> for CacheEncoder<'enc, 'a, 'tcx, E>
     where E: 'enc + ty_codec::TyEncoder
 {
     #[inline]
-    fn specialized_encode(&mut self, ty: &ty::Ty<'tcx>) -> Result<(), Self::Error> {
+    fn specialized_encode(&mut self, ty: &Ty<'tcx>) -> Result<(), Self::Error> {
         ty_codec::encode_with_shorthand(self, ty,
             |encoder| &mut encoder.type_shorthands)
     }

src/librustc_mir/borrow_check/nll/constraint_generation.rs

@@ -64,7 +64,7 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
 
     /// We sometimes have `ty` within an rvalue, or within a
     /// call. Make them live at the location where they appear.
-    fn visit_ty(&mut self, ty: &ty::Ty<'tcx>, ty_context: TyContext) {
+    fn visit_ty(&mut self, ty: ty::Ty<'tcx>, ty_context: TyContext) {
         match ty_context {
             TyContext::ReturnTy(SourceInfo { span, .. })
             | TyContext::YieldTy(SourceInfo { span, .. })
@@ -77,7 +77,7 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
                 );
             }
             TyContext::Location(location) => {
-                self.add_regular_live_constraint(*ty, location);
+                self.add_regular_live_constraint(ty, location);
             }
         }
 

src/librustc_mir/monomorphize/partitioning.rs

@@ -228,7 +228,7 @@ pub fn partition<'a, 'tcx, I>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     // functions and statics defined in the local crate.
     let mut initial_partitioning = place_root_mono_items(tcx, mono_items);
 
-    initial_partitioning.codegen_units.iter_mut().for_each(|cgu| cgu.estimate_size(&tcx));
+    initial_partitioning.codegen_units.iter_mut().for_each(|cgu| cgu.estimate_size(tcx));
 
     debug_dump(tcx, "INITIAL PARTITIONING:", initial_partitioning.codegen_units.iter());
 
@@ -247,7 +247,7 @@ pub fn partition<'a, 'tcx, I>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let mut post_inlining = place_inlined_mono_items(initial_partitioning,
                                                             inlining_map);
 
-    post_inlining.codegen_units.iter_mut().for_each(|cgu| cgu.estimate_size(&tcx));
+    post_inlining.codegen_units.iter_mut().for_each(|cgu| cgu.estimate_size(tcx));
 
     debug_dump(tcx, "POST INLINING:", post_inlining.codegen_units.iter());
 

src/librustc_typeck/check/compare_method.rs

@@ -308,7 +308,7 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             };
 
             let mut diag = struct_span_err!(tcx.sess,
-                                            cause.span(&tcx),
+                                            cause.span(tcx),
                                             E0053,
                                             "method `{}` has an incompatible type for trait",
                                             trait_m.ident);
@@ -448,9 +448,9 @@ fn extract_spans_for_error_reporting<'a, 'gcx, 'tcx>(infcx: &infer::InferCtxt<'a
                 }).map(|(ref impl_arg, ref trait_arg)| {
                     (impl_arg.span, Some(trait_arg.span))
                 })
-                .unwrap_or_else(|| (cause.span(&tcx), tcx.hir().span_if_local(trait_m.def_id)))
+                .unwrap_or_else(|| (cause.span(tcx), tcx.hir().span_if_local(trait_m.def_id)))
             } else {
-                (cause.span(&tcx), tcx.hir().span_if_local(trait_m.def_id))
+                (cause.span(tcx), tcx.hir().span_if_local(trait_m.def_id))
             }
         }
         TypeError::Sorts(ExpectedFound { .. }) => {
@@ -483,14 +483,14 @@ fn extract_spans_for_error_reporting<'a, 'gcx, 'tcx>(infcx: &infer::InferCtxt<'a
                              {
                                  (impl_m_output.span(), Some(trait_m_output.span()))
                              } else {
-                                 (cause.span(&tcx), tcx.hir().span_if_local(trait_m.def_id))
+                                 (cause.span(tcx), tcx.hir().span_if_local(trait_m.def_id))
                              }
                          )
             } else {
-                (cause.span(&tcx), tcx.hir().span_if_local(trait_m.def_id))
+                (cause.span(tcx), tcx.hir().span_if_local(trait_m.def_id))
             }
         }
-        _ => (cause.span(&tcx), tcx.hir().span_if_local(trait_m.def_id)),
+        _ => (cause.span(tcx), tcx.hir().span_if_local(trait_m.def_id)),
     }
 }
 
@@ -549,7 +549,7 @@ fn compare_self_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 err.span_label(span, format!("trait method declared without `{}`", self_descr));
             } else {
                 err.note_trait_signature(trait_m.ident.to_string(),
-                                         trait_m.signature(&tcx));
+                                         trait_m.signature(tcx));
             }
             err.emit();
             return Err(ErrorReported);
@@ -569,7 +569,7 @@ fn compare_self_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 err.span_label(span, format!("`{}` used in trait", self_descr));
             } else {
                 err.note_trait_signature(trait_m.ident.to_string(),
-                                         trait_m.signature(&tcx));
+                                         trait_m.signature(tcx));
             }
             err.emit();
             return Err(ErrorReported);
@@ -726,7 +726,7 @@ fn compare_number_of_method_arguments<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 potentially_plural_count(trait_number_args, "parameter")));
         } else {
             err.note_trait_signature(trait_m.ident.to_string(),
-                                     trait_m.signature(&tcx));
+                                     trait_m.signature(tcx));
         }
         err.span_label(impl_span, format!("expected {}, found {}",
             potentially_plural_count(trait_number_args, "parameter"), impl_number_args));

src/librustc_typeck/check/mod.rs

@@ -1667,7 +1667,7 @@ fn check_impl_items_against_trait<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 err.span_label(span, format!("`{}` from trait", trait_item.ident));
             } else {
                 err.note_trait_signature(trait_item.ident.to_string(),
-                                         trait_item.signature(&tcx));
+                                         trait_item.signature(tcx));
             }
         }
         err.emit();

src/librustdoc/clean/auto_trait.rs

@@ -14,7 +14,7 @@ pub struct AutoTraitFinder<'a, 'tcx> {
 
 impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
     pub fn new(cx: &'a core::DocContext<'tcx>) -> Self {
-        let f = auto::AutoTraitFinder::new(&cx.tcx);
+        let f = auto::AutoTraitFinder::new(cx.tcx);
 
         AutoTraitFinder { cx, f }
     }