A few cosmetic improvements.

src/librustc/hir/mod.rs

@@ -2234,7 +2234,7 @@ pub enum UseKind {
 #[derive(RustcEncodable, RustcDecodable, Debug, HashStable)]
 pub struct TraitRef {
     pub path: P<Path>,
-    // Don't hash the ref_id. It is tracked via the thing it is used to access
+    // Don't hash the `ref_id`. It is tracked via the thing it is used to access.
     #[stable_hasher(ignore)]
     pub hir_ref_id: HirId,
 }

src/librustc/ty/mod.rs

@@ -904,7 +904,7 @@ pub struct Generics {
     pub parent_count: usize,
     pub params: Vec<GenericParamDef>,
 
-    /// Reverse map to the `index` field of each `GenericParamDef`
+    /// Reverse map to the `index` field of each `GenericParamDef`.
     #[stable_hasher(ignore)]
     pub param_def_id_to_index: FxHashMap<DefId, u32>,
 
@@ -1252,7 +1252,7 @@ impl<'tcx> TraitPredicate<'tcx> {
 
 impl<'tcx> PolyTraitPredicate<'tcx> {
     pub fn def_id(&self) -> DefId {
-        // Ok to skip binder since trait def-ID does not care about regions.
+        // Ok to skip binder since trait `DefId` does not care about regions.
         self.skip_binder().def_id()
     }
 }
@@ -1319,7 +1319,7 @@ impl<'tcx> PolyProjectionPredicate<'tcx> {
     /// Note that this is not the `DefId` of the `TraitRef` containing this
     /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
     pub fn projection_def_id(&self) -> DefId {
-        // Ok to skip binder since trait def-ID does not care about regions.
+        // Ok to skip binder since trait `DefId` does not care about regions.
         self.skip_binder().projection_ty.item_def_id
     }
 }
@@ -1646,10 +1646,10 @@ pub type PlaceholderConst = Placeholder<BoundVar>;
 /// particular point.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
 pub struct ParamEnv<'tcx> {
-    /// Obligations that the caller must satisfy. This is basically
+    /// `Obligation`s that the caller must satisfy. This is basically
     /// the set of bounds on the in-scope type parameters, translated
-    /// into Obligations, and elaborated and normalized.
-    pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
+    /// into `Obligation`s, and elaborated and normalized.
+    pub caller_bounds: &'tcx List<(ty::Predicate<'tcx>, Span)>,
 
     /// Typically, this is `Reveal::UserFacing`, but during codegen we
     /// want `Reveal::All` -- note that this is always paired with an
@@ -2796,7 +2796,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 _ => false,
             }
         } else {
-            match self.def_kind(def_id).expect("no def for def-id") {
+            match self.def_kind(def_id).expect("no def for `DefId`") {
                 DefKind::AssocConst
                 | DefKind::Method
                 | DefKind::AssocTy => true,

src/librustc/ty/sty.rs

@@ -646,7 +646,7 @@ impl<'tcx> List<ExistentialPredicate<'tcx>> {
     ///
     /// A Rust trait object type consists (in addition to a lifetime bound)
     /// of a set of trait bounds, which are separated into any number
-    /// of auto-trait bounds, and at most 1 non-auto-trait bound. The
+    /// of auto-trait bounds, and at most one non-auto-trait bound. The
     /// non-auto-trait bound is called the "principal" of the trait
     /// object.
     ///
@@ -680,7 +680,8 @@ impl<'tcx> List<ExistentialPredicate<'tcx>> {
 
     #[inline]
     pub fn projection_bounds<'a>(&'a self) ->
-        impl Iterator<Item=ExistentialProjection<'tcx>> + 'a {
+        impl Iterator<Item = ExistentialProjection<'tcx>> + 'a
+    {
         self.iter().filter_map(|predicate| {
             match *predicate {
                 ExistentialPredicate::Projection(p) => Some(p),
@@ -690,7 +691,7 @@ impl<'tcx> List<ExistentialPredicate<'tcx>> {
     }
 
     #[inline]
-    pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item=DefId> + 'a {
+    pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item = DefId> + 'a {
         self.iter().filter_map(|predicate| {
             match *predicate {
                 ExistentialPredicate::AutoTrait(d) => Some(d),
@@ -711,17 +712,17 @@ impl<'tcx> Binder<&'tcx List<ExistentialPredicate<'tcx>>> {
 
     #[inline]
     pub fn projection_bounds<'a>(&'a self) ->
-        impl Iterator<Item=PolyExistentialProjection<'tcx>> + 'a {
+        impl Iterator<Item = PolyExistentialProjection<'tcx>> + 'a {
         self.skip_binder().projection_bounds().map(Binder::bind)
     }
 
     #[inline]
-    pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item=DefId> + 'a {
+    pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item = DefId> + 'a {
         self.skip_binder().auto_traits()
     }
 
     pub fn iter<'a>(&'a self)
-        -> impl DoubleEndedIterator<Item=Binder<ExistentialPredicate<'tcx>>> + 'tcx {
+        -> impl DoubleEndedIterator<Item = Binder<ExistentialPredicate<'tcx>>> + 'tcx {
         self.skip_binder().iter().cloned().map(Binder::bind)
     }
 }

src/librustc_codegen_llvm/debuginfo/metadata.rs

@@ -450,11 +450,11 @@ fn subroutine_type_metadata(
         false);
 }
 
-// FIXME(1563) This is all a bit of a hack because 'trait pointer' is an ill-
-// defined concept. For the case of an actual trait pointer (i.e., Box<Trait>,
-// &Trait), trait_object_type should be the whole thing (e.g, Box<Trait>) and
-// trait_type should be the actual trait (e.g., Trait). Where the trait is part
-// of a DST struct, there is no trait_object_type and the results of this
+// FIXME(1563): This is all a bit of a hack because 'trait pointer' is an ill-
+// defined concept. For the case of an actual trait pointer (i.e., `Box<Trait>`,
+// `&Trait`), `trait_object_type` should be the whole thing (e.g, `Box<Trait>`) and
+// `trait_type` should be the actual trait (e.g., `Trait`). Where the trait is part
+// of a DST struct, there is no `trait_object_type` and the results of this
 // function will be a little bit weird.
 fn trait_pointer_metadata(
     cx: &CodegenCx<'ll, 'tcx>,
@@ -464,13 +464,13 @@ fn trait_pointer_metadata(
 ) -> &'ll DIType {
     // The implementation provided here is a stub. It makes sure that the trait
     // type is assigned the correct name, size, namespace, and source location.
-    // But it does not describe the trait's methods.
+    // However, it does not describe the trait's methods.
 
     let containing_scope = match trait_type.sty {
         ty::Dynamic(ref data, ..) =>
             data.principal_def_id().map(|did| get_namespace_for_item(cx, did)),
         _ => {
-            bug!("debuginfo: Unexpected trait-object type in \
+            bug!("debuginfo: unexpected trait-object type in \
                   trait_pointer_metadata(): {:?}",
                  trait_type);
         }

src/librustc_privacy/lib.rs

@@ -1056,8 +1056,9 @@ impl<'a, 'tcx> Visitor<'tcx> for TypePrivacyVisitor<'a, 'tcx> {
             }
             for (poly_predicate, _) in bounds.projection_bounds {
                 let tcx = self.tcx;
-                if self.visit(poly_predicate.skip_binder().ty) ||
-                   self.visit_trait(poly_predicate.skip_binder().projection_ty.trait_ref(tcx)) {
+                if self.visit(poly_predicate.skip_binder().ty)
+                    || self.visit_trait(poly_predicate.skip_binder().projection_ty.trait_ref(tcx))
+                {
                     return;
                 }
             }

src/librustc_typeck/astconv.rs

@@ -1515,7 +1515,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                    assoc_name: ast::Ident,
                                    span: Span)
         -> Result<ty::PolyTraitRef<'tcx>, ErrorReported>
-        where I: Iterator<Item=ty::PolyTraitRef<'tcx>>
+        where I: Iterator<Item = ty::PolyTraitRef<'tcx>>
     {
         let bound = match bounds.next() {
             Some(bound) => bound,
@@ -1524,8 +1524,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                  "associated type `{}` not found for `{}`",
                                  assoc_name,
                                  ty_param_name)
-                  .span_label(span, format!("associated type `{}` not found", assoc_name))
-                  .emit();
+                    .span_label(span, format!("associated type `{}` not found", assoc_name))
+                    .emit();
                 return Err(ErrorReported);
             }
         };
@@ -1544,7 +1544,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     item.kind == ty::AssocKind::Type &&
                         self.tcx().hygienic_eq(assoc_name, item.ident, bound.def_id())
                 })
-                .and_then(|item| self.tcx().hir().span_if_local(item.def_id));
+                    .and_then(|item| self.tcx().hir().span_if_local(item.def_id));
 
                 if let Some(span) = bound_span {
                     err.span_label(span, format!("ambiguous `{}` from `{}`",

src/librustc_typeck/check/mod.rs

@@ -2030,7 +2030,7 @@ fn report_unexpected_variant_res(tcx: TyCtxt<'_>, res: Res, span: Span, qpath: &
 impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
     fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.tcx
-        }
+    }
 
     fn get_type_parameter_bounds(&self, _: Span, def_id: DefId)
                                  -> &'tcx ty::GenericPredicates<'tcx>

src/librustc_typeck/collect.rs

@@ -226,7 +226,7 @@ impl AstConv<'tcx> for ItemCtxt<'tcx> {
         if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
             self.tcx().mk_projection(item_def_id, trait_ref.substs)
         } else {
-            // no late-bound regions, we can just ignore the binder
+            // There are no late-bound regions; we can just ignore the binder.
             span_err!(
                 self.tcx().sess,
                 span,
@@ -239,17 +239,16 @@ impl AstConv<'tcx> for ItemCtxt<'tcx> {
     }
 
     fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
-        // types in item signatures are not normalized, to avoid undue
-        // dependencies.
+        // Types in item signatures are not normalized to avoid undue dependencies.
         ty
     }
 
     fn set_tainted_by_errors(&self) {
-        // no obvious place to track this, so just let it go
+        // There's no obvious place to track this, so just let it go.
     }
 
     fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
-        // no place to record types from signatures?
+        // There's no place to record types from signatures?
     }
 }
 
@@ -260,8 +259,8 @@ fn type_param_predicates(
     use rustc::hir::*;
 
     // In the AST, bounds can derive from two places. Either
-    // written inline like `<T : Foo>` or in a where clause like
-    // `where T : Foo`.
+    // written inline like `<T: Foo>` or in a where-clause like
+    // `where T: Foo`.
 
     let param_id = tcx.hir().as_local_hir_id(def_id).unwrap();
     let param_owner = tcx.hir().ty_param_owner(param_id);
@@ -334,7 +333,7 @@ fn type_param_predicates(
 impl ItemCtxt<'tcx> {
     /// Finds bounds from `hir::Generics`. This requires scanning through the
     /// AST. We do this to avoid having to convert *all* the bounds, which
-    /// would create artificial cycles. Instead we can only convert the
+    /// would create artificial cycles. Instead, we can only convert the
     /// bounds for a type parameter `X` if `X::Foo` is used.
     fn type_parameter_bounds_in_generics(
         &self,
@@ -2292,7 +2291,7 @@ fn explicit_predicates_of(
 /// Converts a specific `GenericBound` from the AST into a set of
 /// predicates that apply to the self type. A vector is returned
 /// because this can be anywhere from zero predicates (`T: ?Sized` adds no
-/// predicates) to one (`T: Foo`) to many (`T: Bar<X=i32>` adds `T: Bar`
+/// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar`
 /// and `<T as Bar>::X == i32`).
 fn predicates_from_bound<'tcx>(
     astconv: &dyn AstConv<'tcx>,