diff --git a/src/librustc/hir/intravisit.rs b/src/librustc/hir/intravisit.rs
index 9b5b53e891b..fef33939fac 100644
--- a/src/librustc/hir/intravisit.rs
+++ b/src/librustc/hir/intravisit.rs
@@ -648,15 +648,15 @@ pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V,
                                              path_span: Span,
                                              segment: &'v PathSegment) {
     visitor.visit_name(path_span, segment.name);
-    if let Some(ref parameters) = segment.parameters {
-        visitor.visit_generic_args(path_span, parameters);
+    if let Some(ref args) = segment.args {
+        visitor.visit_generic_args(path_span, args);
     }
 }
 
 pub fn walk_generic_args<'v, V: Visitor<'v>>(visitor: &mut V,
                                                 _path_span: Span,
                                                 generic_args: &'v GenericArgs) {
-    walk_list!(visitor, visit_generic_arg, &generic_args.parameters);
+    walk_list!(visitor, visit_generic_arg, &generic_args.args);
     walk_list!(visitor, visit_assoc_type_binding, &generic_args.bindings);
 }
 
diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 4b090e88c40..831a689a349 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -59,6 +59,7 @@ use std::fmt::Debug;
 use std::iter;
 use std::mem;
 use syntax::attr;
+use syntax::ast;
 use syntax::ast::*;
 use syntax::errors;
 use syntax::ext::hygiene::{Mark, SyntaxContext};
@@ -1039,14 +1040,14 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn lower_generic_arg(&mut self,
-                        p: &AngleBracketedParam,
+                        p: &ast::GenericArg,
                         itctx: ImplTraitContext)
-                        -> GenericArg {
+                        -> hir::GenericArg {
         match p {
-            AngleBracketedParam::Lifetime(lt) => {
+            ast::GenericArg::Lifetime(lt) => {
                 GenericArg::Lifetime(self.lower_lifetime(&lt))
             }
-            AngleBracketedParam::Type(ty) => {
+            ast::GenericArg::Type(ty) => {
                 GenericArg::Type(self.lower_ty(&ty, itctx))
             }
         }
@@ -1684,8 +1685,7 @@ impl<'a> LoweringContext<'a> {
         parenthesized_generic_args: ParenthesizedGenericArgs,
         itctx: ImplTraitContext,
     ) -> hir::PathSegment {
-        let (mut generic_args, infer_types) =
-            if let Some(ref generic_args) = segment.parameters {
+        let (mut generic_args, infer_types) = if let Some(ref generic_args) = segment.args {
             let msg = "parenthesized parameters may only be used with a trait";
             match **generic_args {
                 GenericArgs::AngleBracketed(ref data) => {
@@ -1715,13 +1715,16 @@ impl<'a> LoweringContext<'a> {
         };
 
         if !generic_args.parenthesized && generic_args.lifetimes().count() == 0 {
-            generic_args.parameters = (0..expected_lifetimes).map(|_| {
-                GenericArg::Lifetime(self.elided_lifetime(path_span))
-            }).chain(generic_args.parameters.into_iter()).collect();
+            generic_args.args =
+                self.elided_path_lifetimes(path_span, expected_lifetimes)
+                    .into_iter()
+                    .map(|lt| GenericArg::Lifetime(lt))
+                    .chain(generic_args.args.into_iter())
+                    .collect();
         }
 
         hir::PathSegment::new(
-            self.lower_ident(segment.identifier),
+            self.lower_ident(segment.ident),
             generic_args,
             infer_types
         )
@@ -1729,13 +1732,13 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_angle_bracketed_parameter_data(
         &mut self,
-        data: &AngleBracketedParameterData,
+        data: &AngleBracketedArgs,
         param_mode: ParamMode,
         itctx: ImplTraitContext,
     ) -> (hir::GenericArgs, bool) {
-        let &AngleBracketedParameterData { ref parameters, ref bindings, .. } = data;
+        let &AngleBracketedArgs { ref args, ref bindings, .. } = data;
         (hir::GenericArgs {
-            parameters: parameters.iter().map(|p| self.lower_generic_arg(p, itctx)).collect(),
+            args: args.iter().map(|p| self.lower_generic_arg(p, itctx)).collect(),
             bindings: bindings.iter().map(|b| self.lower_ty_binding(b, itctx)).collect(),
             parenthesized: false,
         },
@@ -1755,23 +1758,11 @@ impl<'a> LoweringContext<'a> {
             AnonymousLifetimeMode::PassThrough,
             |this| {
                 const DISALLOWED: ImplTraitContext = ImplTraitContext::Disallowed;
-                let &ParenthesizedParameterData {
-                    ref inputs,
-                    ref output,
-                    span,
-                } = data;
-                let inputs = inputs
-                    .iter()
-                    .map(|ty| this.lower_ty(ty, DISALLOWED))
-                    .collect();
+                let &ParenthesizedParameterData { ref inputs, ref output, span } = data;
+                let inputs = inputs.iter().map(|ty| this.lower_ty(ty, DISALLOWED)).collect();
                 let mk_tup = |this: &mut Self, tys, span| {
                     let LoweredNodeId { node_id, hir_id } = this.next_id();
-                    P(hir::Ty {
-                        node: hir::TyTup(tys),
-                        id: node_id,
-                        hir_id,
-                        span,
-                    })
+                    P(hir::Ty { node: hir::TyTup(tys), id: node_id, hir_id, span })
                 };
 
                 (
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index 38a894df3cd..729ac17ae09 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -327,7 +327,7 @@ pub struct PathSegment {
     /// this is more than just simple syntactic sugar; the use of
     /// parens affects the region binding rules, so we preserve the
     /// distinction.
-    pub parameters: Option<P<GenericArgs>>,
+    pub args: Option<P<GenericArgs>>,
 
     /// Whether to infer remaining type parameters, if any.
     /// This only applies to expression and pattern paths, and
@@ -342,30 +342,30 @@ impl PathSegment {
         PathSegment {
             name,
             infer_types: true,
-            parameters: None
+            args: None,
         }
     }
 
-    pub fn new(name: Name, parameters: GenericArgs, infer_types: bool) -> Self {
+    pub fn new(name: Name, args: GenericArgs, infer_types: bool) -> Self {
         PathSegment {
             name,
             infer_types,
-            parameters: if parameters.is_empty() {
+            args: if args.is_empty() {
                 None
             } else {
-                Some(P(parameters))
+                Some(P(args))
             }
         }
     }
 
     // FIXME: hack required because you can't create a static
     // GenericArgs, so you can't just return a &GenericArgs.
-    pub fn with_parameters<F, R>(&self, f: F) -> R
+    pub fn with_args<F, R>(&self, f: F) -> R
         where F: FnOnce(&GenericArgs) -> R
     {
         let dummy = GenericArgs::none();
-        f(if let Some(ref params) = self.parameters {
-            &params
+        f(if let Some(ref args) = self.args {
+            &args
         } else {
             &dummy
         })
@@ -380,12 +380,12 @@ pub enum GenericArg {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub struct GenericArgs {
-    /// The generic parameters for this path segment.
-    pub parameters: HirVec<GenericArg>,
+    /// The generic arguments for this path segment.
+    pub args: HirVec<GenericArg>,
     /// Bindings (equality constraints) on associated types, if present.
     /// E.g., `Foo<A=Bar>`.
     pub bindings: HirVec<TypeBinding>,
-    /// Were parameters written in parenthesized form `Fn(T) -> U`?
+    /// Were arguments written in parenthesized form `Fn(T) -> U`?
     /// This is required mostly for pretty-printing and diagnostics,
     /// but also for changing lifetime elision rules to be "function-like".
     pub parenthesized: bool,
@@ -394,14 +394,14 @@ pub struct GenericArgs {
 impl GenericArgs {
     pub fn none() -> Self {
         Self {
-            parameters: HirVec::new(),
+            args: HirVec::new(),
             bindings: HirVec::new(),
             parenthesized: false,
         }
     }
 
     pub fn is_empty(&self) -> bool {
-        self.parameters.is_empty() && self.bindings.is_empty() && !self.parenthesized
+        self.args.is_empty() && self.bindings.is_empty() && !self.parenthesized
     }
 
     pub fn inputs(&self) -> &[P<Ty>] {
@@ -416,7 +416,7 @@ impl GenericArgs {
     }
 
     pub fn lifetimes(&self) -> impl DoubleEndedIterator<Item = &Lifetime> {
-        self.parameters.iter().filter_map(|p| {
+        self.args.iter().filter_map(|p| {
             if let GenericArg::Lifetime(lt) = p {
                 Some(lt)
             } else {
@@ -426,7 +426,7 @@ impl GenericArgs {
     }
 
     pub fn types(&self) -> impl DoubleEndedIterator<Item = &P<Ty>> {
-        self.parameters.iter().filter_map(|p| {
+        self.args.iter().filter_map(|p| {
             if let GenericArg::Type(ty) = p {
                 Some(ty)
             } else {
diff --git a/src/librustc/hir/print.rs b/src/librustc/hir/print.rs
index f7e98591c11..c12d258b6c7 100644
--- a/src/librustc/hir/print.rs
+++ b/src/librustc/hir/print.rs
@@ -1269,11 +1269,11 @@ impl<'a> State<'a> {
         self.s.word(".")?;
         self.print_name(segment.name)?;
 
-        segment.with_parameters(|parameters| {
-            if !parameters.parameters.is_empty() ||
-                !parameters.bindings.is_empty()
+        segment.with_args(|args| {
+            if !args.args.is_empty() ||
+                !args.bindings.is_empty()
             {
-                self.print_generic_args(&parameters, segment.infer_types, true)
+                self.print_generic_args(&args, segment.infer_types, true)
             } else {
                 Ok(())
             }
@@ -1641,7 +1641,7 @@ impl<'a> State<'a> {
             if segment.name != keywords::CrateRoot.name() &&
                segment.name != keywords::DollarCrate.name() {
                self.print_name(segment.name)?;
-               segment.with_parameters(|parameters| {
+               segment.with_args(|parameters| {
                    self.print_generic_args(parameters,
                                               segment.infer_types,
                                               colons_before_params)
@@ -1673,7 +1673,7 @@ impl<'a> State<'a> {
                     if segment.name != keywords::CrateRoot.name() &&
                        segment.name != keywords::DollarCrate.name() {
                         self.print_name(segment.name)?;
-                        segment.with_parameters(|parameters| {
+                        segment.with_args(|parameters| {
                             self.print_generic_args(parameters,
                                                        segment.infer_types,
                                                        colons_before_params)
@@ -1685,7 +1685,7 @@ impl<'a> State<'a> {
                 self.s.word("::")?;
                 let item_segment = path.segments.last().unwrap();
                 self.print_name(item_segment.name)?;
-                item_segment.with_parameters(|parameters| {
+                item_segment.with_args(|parameters| {
                     self.print_generic_args(parameters,
                                                item_segment.infer_types,
                                                colons_before_params)
@@ -1697,7 +1697,7 @@ impl<'a> State<'a> {
                 self.s.word(">")?;
                 self.s.word("::")?;
                 self.print_name(item_segment.name)?;
-                item_segment.with_parameters(|parameters| {
+                item_segment.with_args(|parameters| {
                     self.print_generic_args(parameters,
                                                item_segment.infer_types,
                                                colons_before_params)
@@ -1734,7 +1734,7 @@ impl<'a> State<'a> {
             let elide_lifetimes = generic_args.lifetimes().all(|lt| lt.is_elided());
             if !elide_lifetimes {
                 start_or_comma(self)?;
-                self.commasep(Inconsistent, &generic_args.parameters, |s, p| {
+                self.commasep(Inconsistent, &generic_args.args, |s, p| {
                     match p {
                         GenericArg::Lifetime(lt) => s.print_lifetime(lt),
                         GenericArg::Type(ty) => s.print_type(ty),
diff --git a/src/librustc/ich/impls_hir.rs b/src/librustc/ich/impls_hir.rs
index 6f655628678..871e399b4f2 100644
--- a/src/librustc/ich/impls_hir.rs
+++ b/src/librustc/ich/impls_hir.rs
@@ -177,7 +177,7 @@ impl_stable_hash_for!(struct hir::Path {
 impl_stable_hash_for!(struct hir::PathSegment {
     name,
     infer_types,
-    parameters
+    args
 });
 
 impl_stable_hash_for!(enum hir::GenericArg {
@@ -186,7 +186,7 @@ impl_stable_hash_for!(enum hir::GenericArg {
 });
 
 impl_stable_hash_for!(struct hir::GenericArgs {
-    parameters,
+    args,
     bindings,
     parenthesized
 });
diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs
index 69818068e9c..39dfa77ea67 100644
--- a/src/librustc/middle/resolve_lifetime.rs
+++ b/src/librustc/middle/resolve_lifetime.rs
@@ -28,7 +28,6 @@ use rustc_data_structures::sync::Lrc;
 use session::Session;
 use std::cell::Cell;
 use std::mem::replace;
-use std::slice;
 use syntax::ast;
 use syntax::attr;
 use syntax::ptr::P;
@@ -155,11 +154,10 @@ impl Region {
         }
     }
 
-    fn subst(self, params: Vec<&hir::Lifetime>, map: &NamedRegionMap) -> Option<Region> {
+    fn subst<'a, L>(self, mut params: L, map: &NamedRegionMap) -> Option<Region>
+            where L: Iterator<Item = &'a hir::Lifetime>  {
         if let Region::EarlyBound(index, _, _) = self {
-            params
-                .get(index as usize)
-                .and_then(|lifetime| map.defs.get(&lifetime.id).cloned())
+            params.nth(index as usize).and_then(|lifetime| map.defs.get(&lifetime.id).cloned())
         } else {
             Some(self)
         }
@@ -603,7 +601,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                         // resolved the same as the `'_` in `&'_ Foo`.
                         //
                         // cc #48468
-                        self.resolve_elided_lifetimes(slice::from_ref(lifetime), false)
+                        self.resolve_elided_lifetimes(vec![lifetime], false)
                     }
                     LifetimeName::Fresh(_) | LifetimeName::Static | LifetimeName::Name(_) => {
                         // If the user wrote an explicit name, use that.
@@ -833,8 +831,8 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
     fn visit_path(&mut self, path: &'tcx hir::Path, _: ast::NodeId) {
         for (i, segment) in path.segments.iter().enumerate() {
             let depth = path.segments.len() - i - 1;
-            if let Some(ref parameters) = segment.parameters {
-                self.visit_segment_parameters(path.def, depth, parameters);
+            if let Some(ref args) = segment.args {
+                self.visit_segment_args(path.def, depth, args);
             }
         }
     }
@@ -1599,24 +1597,24 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         }
     }
 
-    fn visit_segment_parameters(
+    fn visit_segment_args(
         &mut self,
         def: Def,
         depth: usize,
-        params: &'tcx hir::GenericArgs,
+        args: &'tcx hir::GenericArgs,
     ) {
-        if params.parenthesized {
+        if args.parenthesized {
             let was_in_fn_syntax = self.is_in_fn_syntax;
             self.is_in_fn_syntax = true;
-            self.visit_fn_like_elision(params.inputs(), Some(&params.bindings[0].ty));
+            self.visit_fn_like_elision(args.inputs(), Some(&args.bindings[0].ty));
             self.is_in_fn_syntax = was_in_fn_syntax;
             return;
         }
 
-        if params.lifetimes().all(|l| l.is_elided()) {
-            self.resolve_elided_lifetimes(params.lifetimes().collect(), true);
+        if args.lifetimes().all(|l| l.is_elided()) {
+            self.resolve_elided_lifetimes(args.lifetimes().collect(), true);
         } else {
-            for l in params.lifetimes() {
+            for l in args.lifetimes() {
                 self.visit_lifetime(l);
             }
         }
@@ -1688,13 +1686,13 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                     } else {
                         Some(Region::Static)
                     },
-                    Set1::One(r) => r.subst(params.lifetimes().collect(), map),
+                    Set1::One(r) => r.subst(args.lifetimes(), map),
                     Set1::Many => None,
                 })
                 .collect()
         });
 
-        for (i, ty) in params.types().enumerate() {
+        for (i, ty) in args.types().enumerate() {
             if let Some(&lt) = object_lifetime_defaults.get(i) {
                 let scope = Scope::ObjectLifetimeDefault {
                     lifetime: lt,
@@ -1706,7 +1704,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             }
         }
 
-        for b in &params.bindings {
+        for b in &args.bindings {
             self.visit_assoc_type_binding(b);
         }
     }
diff --git a/src/librustc/ty/instance.rs b/src/librustc/ty/instance.rs
index 66edbeff749..8b1c31deb13 100644
--- a/src/librustc/ty/instance.rs
+++ b/src/librustc/ty/instance.rs
@@ -10,6 +10,7 @@
 
 use hir::def_id::DefId;
 use ty::{self, Ty, TypeFoldable, Substs, TyCtxt};
+use ty::subst::Kind;
 use traits;
 use rustc_target::spec::abi::Abi;
 use util::ppaux;
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 447267adfcd..4f5f0c9d740 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -885,73 +885,6 @@ pub struct GenericParamCount {
     pub types: usize,
 }
 
-#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
-pub enum GenericParam {
-    Lifetime(RegionParameterDef),
-    Type(TypeParameterDef),
-}
-
-impl GenericParam {
-    pub fn index(&self) -> u32 {
-        match self {
-            GenericParam::Lifetime(lt) => lt.index,
-            GenericParam::Type(ty)     => ty.index,
-        }
-    }
-}
-
-#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
-pub enum KindIndex {
-    Lifetime,
-    Type,
-}
-
-#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
-pub struct KindIndexed<L, T> {
-    pub lt: L,
-    pub ty: T,
-}
-
-impl<T> KindIndexed<T, T> {
-    pub fn get(&self, idx: KindIndex) -> &T {
-        match idx {
-            KindIndex::Lifetime => &self.lt,
-            KindIndex::Type     => &self.ty,
-        }
-    }
-
-    pub fn iter(&self) -> KindIndexIterator<T> {
-        KindIndexIterator {
-            index: self,
-            next: Some(KindIndex::Lifetime),
-        }
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct KindIndexIterator<'a, T: 'a> {
-    pub index: &'a KindIndexed<T, T>,
-    pub next: Option<KindIndex>,
-}
-
-impl<'a, T> Iterator for KindIndexIterator<'a, T> {
-    type Item = &'a T;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        match self.next {
-            Some(KindIndex::Lifetime) => {
-                self.next = Some(KindIndex::Type);
-                Some(&self.index.lt)
-            }
-            Some(KindIndex::Type) => {
-                self.next = None;
-                Some(&self.index.ty)
-            },
-            None => None,
-        }
-    }
-}
-
 /// Information about the formal type/lifetime parameters associated
 /// with an item or method. Analogous to hir::Generics.
 ///
@@ -1009,34 +942,6 @@ impl<'a, 'gcx, 'tcx> Generics {
         }
     }
 
-    pub fn lifetimes(&self) -> impl DoubleEndedIterator<Item = &RegionParameterDef> {
-        self.parameters.iter().filter_map(|p| {
-            if let GenericParam::Lifetime(lt) = p {
-                Some(lt)
-            } else {
-                None
-            }
-        })
-    }
-
-    pub fn types(&self) -> impl DoubleEndedIterator<Item = &TypeParameterDef> {
-        self.parameters.iter().filter_map(|p| {
-            if let GenericParam::Type(ty) = p {
-                Some(ty)
-            } else {
-                None
-            }
-        })
-    }
-
-    pub fn parent_lifetimes(&self) -> u32 {
-        *self.parent_params.get(KindIndex::Lifetime)
-    }
-
-    pub fn parent_types(&self) -> u32 {
-        *self.parent_params.get(KindIndex::Type)
-    }
-
     pub fn region_param(&'tcx self,
                         param: &EarlyBoundRegion,
                         tcx: TyCtxt<'a, 'gcx, 'tcx>)
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index 322924535d1..7c8ba63c15e 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -40,6 +40,7 @@ use rustc::middle::weak_lang_items;
 use rustc::mir::mono::{Linkage, Visibility, Stats};
 use rustc::middle::cstore::{EncodedMetadata};
 use rustc::ty::{self, Ty, TyCtxt};
+use rustc::ty::subst::Kind;
 use rustc::ty::layout::{self, Align, TyLayout, LayoutOf};
 use rustc::ty::query::Providers;
 use rustc::dep_graph::{DepNode, DepConstructor};
diff --git a/src/librustc_driver/pretty.rs b/src/librustc_driver/pretty.rs
index 834bd0c32ed..7468f01de70 100644
--- a/src/librustc_driver/pretty.rs
+++ b/src/librustc_driver/pretty.rs
@@ -677,7 +677,7 @@ impl<'a> ReplaceBodyWithLoop<'a> {
                     ast::TyKind::Paren(ref subty) => involves_impl_trait(subty),
                     ast::TyKind::Tup(ref tys) => any_involves_impl_trait(tys.iter()),
                     ast::TyKind::Path(_, ref path) => path.segments.iter().any(|seg| {
-                        match seg.parameters.as_ref().map(|p| &**p) {
+                        match seg.args.as_ref().map(|p| &**p) {
                             None => false,
                             Some(&ast::GenericArgs::AngleBracketed(ref data)) =>
                                 any_involves_impl_trait(data.types().into_iter()) ||
diff --git a/src/librustc_mir/hair/pattern/check_match.rs b/src/librustc_mir/hair/pattern/check_match.rs
index 7cef8a75aa6..2c58bd8e79b 100644
--- a/src/librustc_mir/hair/pattern/check_match.rs
+++ b/src/librustc_mir/hair/pattern/check_match.rs
@@ -295,7 +295,7 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
             );
             let label_msg = match pat.node {
                 PatKind::Path(hir::QPath::Resolved(None, ref path))
-                        if path.segments.len() == 1 && path.segments[0].parameters.is_none() => {
+                        if path.segments.len() == 1 && path.segments[0].args.is_none() => {
                     format!("interpreted as a {} pattern, not new variable", path.def.kind_name())
                 }
                 _ => format!("pattern `{}` not covered", pattern_string),
diff --git a/src/librustc_mir/monomorphize/mod.rs b/src/librustc_mir/monomorphize/mod.rs
index bf544e5120c..3afe9991c68 100644
--- a/src/librustc_mir/monomorphize/mod.rs
+++ b/src/librustc_mir/monomorphize/mod.rs
@@ -13,6 +13,7 @@ use rustc::middle::lang_items::DropInPlaceFnLangItem;
 use rustc::traits;
 use rustc::ty::adjustment::CustomCoerceUnsized;
 use rustc::ty::{self, Ty, TyCtxt};
+use rustc::ty::subst::Kind;
 
 pub use rustc::ty::Instance;
 pub use self::item::{MonoItem, MonoItemExt};
diff --git a/src/librustc_passes/ast_validation.rs b/src/librustc_passes/ast_validation.rs
index 39e0a539258..63c8bd3d1f7 100644
--- a/src/librustc_passes/ast_validation.rs
+++ b/src/librustc_passes/ast_validation.rs
@@ -230,9 +230,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
         // }
         // foo!(bar::baz<T>);
         use_tree.prefix.segments.iter().find(|segment| {
-            segment.parameters.is_some()
+            segment.args.is_some()
         }).map(|segment| {
-            self.err_handler().span_err(segment.parameters.as_ref().unwrap().span(),
+            self.err_handler().span_err(segment.args.as_ref().unwrap().span(),
                                         "generic arguments in import path");
         });
 
@@ -398,8 +398,8 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
     fn visit_vis(&mut self, vis: &'a Visibility) {
         match vis.node {
             VisibilityKind::Restricted { ref path, .. } => {
-                path.segments.iter().find(|segment| segment.parameters.is_some()).map(|segment| {
-                    self.err_handler().span_err(segment.parameters.as_ref().unwrap().span(),
+                path.segments.iter().find(|segment| segment.args.is_some()).map(|segment| {
+                    self.err_handler().span_err(segment.args.as_ref().unwrap().span(),
                                                 "generic arguments in visibility path");
                 });
             }
@@ -521,10 +521,10 @@ impl<'a> Visitor<'a> for NestedImplTraitVisitor<'a> {
             visit::walk_ty(self, t);
         }
     }
-    fn visit_path_parameters(&mut self, _: Span, path_parameters: &'a PathParameters) {
-        match *path_parameters {
-            PathParameters::AngleBracketed(ref params) => {
-                for type_ in &params.types {
+    fn visit_generic_args(&mut self, _: Span, generic_args: &'a GenericArgs) {
+        match *generic_args {
+            GenericArgs::AngleBracketed(ref params) => {
+                for type_ in params.types() {
                     self.visit_ty(type_);
                 }
                 for type_binding in &params.bindings {
@@ -533,7 +533,7 @@ impl<'a> Visitor<'a> for NestedImplTraitVisitor<'a> {
                     self.with_impl_trait(None, |this| visit::walk_ty(this, &type_binding.ty));
                 }
             }
-            PathParameters::Parenthesized(ref params) => {
+            GenericArgs::Parenthesized(ref params) => {
                 for type_ in &params.inputs {
                     self.visit_ty(type_);
                 }
@@ -590,7 +590,7 @@ impl<'a> Visitor<'a> for ImplTraitProjectionVisitor<'a> {
                 //
                 // To implement this, we disallow `impl Trait` from `qself`
                 // (for cases like `<impl Trait>::Foo>`)
-                // but we allow `impl Trait` in `PathParameters`
+                // but we allow `impl Trait` in `GenericArgs`
                 // iff there are no more PathSegments.
                 if let Some(ref qself) = *qself {
                     // `impl Trait` in `qself` is always illegal
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index de7a3dc5cee..649e8858b09 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -437,8 +437,8 @@ impl<'a> Resolver<'a> {
         let def = self.resolve_macro_to_def_inner(scope, path, kind, force);
         if def != Err(Determinacy::Undetermined) {
             // Do not report duplicated errors on every undetermined resolution.
-            path.segments.iter().find(|segment| segment.parameters.is_some()).map(|segment| {
-                self.session.span_err(segment.parameters.as_ref().unwrap().span(),
+            path.segments.iter().find(|segment| segment.args.is_some()).map(|segment| {
+                self.session.span_err(segment.args.as_ref().unwrap().span(),
                                       "generic arguments in macro path");
             });
         }
diff --git a/src/librustc_save_analysis/dump_visitor.rs b/src/librustc_save_analysis/dump_visitor.rs
index 6d13548b9ad..fa055d246f3 100644
--- a/src/librustc_save_analysis/dump_visitor.rs
+++ b/src/librustc_save_analysis/dump_visitor.rs
@@ -818,10 +818,10 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
         }
         self.dump_path_ref(id, path);
 
-        // Type parameters
+        // Type arguments
         for seg in &path.segments {
-            if let Some(ref params) = seg.parameters {
-                match **params {
+            if let Some(ref args) = seg.args {
+                match **args {
                     ast::GenericArgs::AngleBracketed(ref data) => for t in data.types() {
                         self.visit_ty(t);
                     },
@@ -905,8 +905,8 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
         }
 
         // Explicit types in the turbo-fish.
-        if let Some(ref params) = seg.parameters {
-            if let ast::GenericArgs::AngleBracketed(ref data) = **params {
+        if let Some(ref args) = seg.args {
+            if let ast::GenericArgs::AngleBracketed(ref data) = **args {
                 for t in data.types() {
                     self.visit_ty(t);
                 }
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index c1022c09de3..4f03698d9b1 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -692,8 +692,8 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
             if path.segments.len() != 1 {
                 return false;
             }
-            if let Some(ref params) = path.segments[0].parameters {
-                if let ast::GenericArgs::Parenthesized(_) = **params {
+            if let Some(ref args) = path.segments[0].args {
+                if let ast::GenericArgs::Parenthesized(_) = **args {
                     return true;
                 }
             }
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 656045c970f..be4c423e959 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -177,11 +177,11 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
     {
 
         let (substs, assoc_bindings) =
-            item_segment.with_parameters(|parameters| {
+            item_segment.with_args(|args| {
                 self.create_substs_for_ast_path(
                     span,
                     def_id,
-                    parameters,
+                    args,
                     item_segment.infer_types,
                     None)
             });
@@ -199,7 +199,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
     fn create_substs_for_ast_path(&self,
         span: Span,
         def_id: DefId,
-        parameters: &hir::GenericArgs,
+        args: &hir::GenericArgs,
         infer_types: bool,
         self_ty: Option<Ty<'tcx>>)
         -> (&'tcx Substs<'tcx>, Vec<ConvertedBinding<'tcx>>)
@@ -207,15 +207,15 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
         let tcx = self.tcx();
 
         debug!("create_substs_for_ast_path(def_id={:?}, self_ty={:?}, \
-               parameters={:?})",
-               def_id, self_ty, parameters);
+               args={:?})",
+               def_id, self_ty, args);
 
         // If the type is parameterized by this region, then replace this
         // region with the current anon region binding (in other words,
         // whatever & would get replaced with).
         let decl_generics = tcx.generics_of(def_id);
-        let ty_provided = parameters.types().len();
-        let lt_provided = parameters.lifetimes().len();
+        let ty_provided = args.types().count();
+        let lt_provided = args.lifetimes().count();
 
         let mut lt_accepted = 0;
         let mut ty_params = ParamRange { required: 0, accepted: 0 };
@@ -269,7 +269,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
             match param.kind {
                 GenericParamDefKind::Lifetime => {
                     let i = param.index as usize - own_self;
-                    if let Some(lifetime) = parameters.lifetimes().get(i) {
+                    if let Some(lifetime) = args.lifetimes().nth(i) {
                         self.ast_region_to_region(lifetime, Some(param)).into()
                     } else {
                         tcx.types.re_static.into()
@@ -286,7 +286,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
                     let i = i - (lt_accepted + own_self);
                     if i < ty_provided {
                         // A provided type parameter.
-                        self.ast_ty_to_ty(&parameters.types()[i]).into()
+                        self.ast_ty_to_ty(&args.types().nth(i).unwrap()).into()
                     } else if infer_types {
                         // No type parameters were provided, we can infer all.
                         if !default_needs_object_self(param) {
@@ -330,7 +330,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
             }
         });
 
-        let assoc_bindings = parameters.bindings.iter().map(|binding| {
+        let assoc_bindings = args.bindings.iter().map(|binding| {
             ConvertedBinding {
                 item_name: binding.name,
                 ty: self.ast_ty_to_ty(&binding.ty),
@@ -451,7 +451,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
         let trait_def = self.tcx().trait_def(trait_def_id);
 
         if !self.tcx().features().unboxed_closures &&
-           trait_segment.with_parameters(|p| p.parenthesized) != trait_def.paren_sugar {
+           trait_segment.with_args(|p| p.parenthesized) != trait_def.paren_sugar {
             // For now, require that parenthetical notation be used only with `Fn()` etc.
             let msg = if trait_def.paren_sugar {
                 "the precise format of `Fn`-family traits' type parameters is subject to change. \
@@ -463,7 +463,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
                              span, GateIssue::Language, msg);
         }
 
-        trait_segment.with_parameters(|parameters| {
+        trait_segment.with_args(|parameters| {
             self.create_substs_for_ast_path(span,
                                             trait_def_id,
                                             parameters,
@@ -970,8 +970,8 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
 
     pub fn prohibit_type_params(&self, segments: &[hir::PathSegment]) {
         for segment in segments {
-            segment.with_parameters(|params| {
-                for p in &params.parameters {
+            segment.with_args(|params| {
+                for p in &params.args {
                     let (mut span_err, span, kind) = match p {
                         hir::GenericArg::Lifetime(lt) => {
                             (struct_span_err!(self.tcx().sess, lt.span, E0110,
diff --git a/src/librustc_typeck/check/method/confirm.rs b/src/librustc_typeck/check/method/confirm.rs
index 3274c449daa..bb5bdd4dc77 100644
--- a/src/librustc_typeck/check/method/confirm.rs
+++ b/src/librustc_typeck/check/method/confirm.rs
@@ -59,7 +59,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             "confirm(unadjusted_self_ty={:?}, pick={:?}, generic_args={:?})",
             unadjusted_self_ty,
             pick,
-            segment.parameters,
+            segment.args,
         );
 
         let mut confirm_cx = ConfirmContext::new(self, span, self_expr, call_expr);
@@ -321,7 +321,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
         // Create subst for early-bound lifetime parameters, combining
         // parameters from the type and those from the method.
         assert_eq!(method_generics.parent_count, parent_substs.len());
-        let provided = &segment.parameters;
+        let provided = &segment.args;
         let own_counts = method_generics.own_counts();
         Substs::for_item(self.tcx, pick.item.def_id, |param, _| {
             let i = param.index as usize;
@@ -331,7 +331,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
                 match param.kind {
                     GenericParamDefKind::Lifetime => {
                         if let Some(lifetime) = provided.as_ref().and_then(|p| {
-                            p.lifetimes().get(i - parent_substs.len())
+                            p.lifetimes().nth(i - parent_substs.len())
                         }) {
                             return AstConv::ast_region_to_region(
                                 self.fcx, lifetime, Some(param)).into();
@@ -339,7 +339,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
                     }
                     GenericParamDefKind::Type {..} => {
                         if let Some(ast_ty) = provided.as_ref().and_then(|p| {
-                            p.types().get(i - parent_substs.len() - own_counts.lifetimes)
+                            p.types().nth(i - parent_substs.len() - own_counts.lifetimes)
                         }) {
                             return self.to_ty(ast_ty).into();
                         }
@@ -347,7 +347,6 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
                 }
                 self.var_for_def(self.span, param)
             }
-            self.type_var_for_def(self.span, def, cur_substs)
         })
     }
 
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index ef61c99ae01..5af3d2fc42c 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -4834,7 +4834,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             match param.kind {
                 GenericParamDefKind::Lifetime => {
                     let lifetimes = segment.map_or(vec![], |(s, _)| {
-                        s.parameters.as_ref().map_or(vec![], |p| p.lifetimes())
+                        s.args.as_ref().map_or(vec![], |p| p.lifetimes().collect())
                     });
 
                     if let Some(lifetime) = lifetimes.get(i) {
@@ -4845,7 +4845,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 }
                 GenericParamDefKind::Type {..} => {
                     let (types, infer_types) = segment.map_or((vec![], true), |(s, _)| {
-                        (s.parameters.as_ref().map_or(vec![], |p| |p| p.types()), s.infer_types)
+                        (s.args.as_ref().map_or(vec![], |p| p.types().collect()), s.infer_types)
                     });
 
                     // Skip over the lifetimes in the same segment.
@@ -4962,7 +4962,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                   supress_mismatch_error: bool) {
         let (lifetimes, types, infer_types, bindings) = segment.map_or(
             (vec![], vec![], true, &[][..]),
-            |(s, _)| s.parameters.as_ref().map_or(
+            |(s, _)| s.args.as_ref().map_or(
                 (vec![], vec![], s.infer_types, &[][..]),
                 |p| (p.lifetimes().collect(), p.types().collect(),
                      s.infer_types, &p.bindings[..])));
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 70367dd2461..58e804fc13f 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -973,13 +973,6 @@ fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                       .map(|param| (param.def_id, param.index))
                                       .collect();
 
-    let parent_params = ty::KindIndexed { lt: parent_regions, ty: parent_types };
-    let lifetimes: Vec<ty::GenericParam> =
-        regions.into_iter().map(|lt| ty::GenericParam::Lifetime(lt)).collect();
-    let types: Vec<ty::GenericParam> =
-        types.into_iter().map(|ty| ty::GenericParam::Type(ty)).collect();
-    let parameters = lifetimes.into_iter().chain(types.into_iter()).collect();
-
     tcx.alloc_generics(ty::Generics {
         parent: parent_def_id,
         parent_count,
diff --git a/src/librustdoc/clean/auto_trait.rs b/src/librustdoc/clean/auto_trait.rs
index da749fca2a9..4418c107223 100644
--- a/src/librustdoc/clean/auto_trait.rs
+++ b/src/librustdoc/clean/auto_trait.rs
@@ -244,9 +244,8 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
         None
     }
 
-    fn generics_to_path_params(&self, generics: ty::Generics) -> hir::PathParameters {
-        let mut lifetimes = vec![];
-        let mut types = vec![];
+    fn generics_to_path_params(&self, generics: ty::Generics) -> hir::GenericArgs {
+        let mut args = vec![];
 
         for param in generics.params.iter() {
             match param.kind {
@@ -257,21 +256,20 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
                         hir::LifetimeName::Name(param.name.as_symbol())
                     };
 
-                    lifetimes.push(hir::Lifetime {
+                    args.push(hir::GenericArg::Lifetime(hir::Lifetime {
                         id: ast::DUMMY_NODE_ID,
                         span: DUMMY_SP,
                         name,
-                    });
+                    }));
                 }
                 ty::GenericParamDefKind::Type {..} => {
-                    types.push(P(self.ty_param_to_ty(param.clone())));
+                    args.push(hir::GenericArg::Type(P(self.ty_param_to_ty(param.clone()))));
                 }
             }
         }
 
-        hir::PathParameters {
-            lifetimes: HirVec::from_vec(lifetimes),
-            types: HirVec::from_vec(types),
+        hir::GenericArgs {
+            args: HirVec::from_vec(args),
             bindings: HirVec::new(),
             parenthesized: false,
         }
@@ -555,9 +553,9 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
                             let mut new_path = path.clone();
                             let last_segment = new_path.segments.pop().unwrap();
 
-                            let (old_input, old_output) = match last_segment.params {
-                                PathParameters::AngleBracketed { types, .. } => (types, None),
-                                PathParameters::Parenthesized { inputs, output, .. } => {
+                            let (old_input, old_output) = match last_segment.args {
+                                GenericArgs::AngleBracketed { types, .. } => (types, None),
+                                GenericArgs::Parenthesized { inputs, output, .. } => {
                                     (inputs, output)
                                 }
                             };
@@ -569,14 +567,14 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
                                 );
                             }
 
-                            let new_params = PathParameters::Parenthesized {
+                            let new_params = GenericArgs::Parenthesized {
                                 inputs: old_input,
                                 output,
                             };
 
                             new_path.segments.push(PathSegment {
                                 name: last_segment.name,
-                                params: new_params,
+                                args: new_params,
                             });
 
                             Type::ResolvedPath {
@@ -793,13 +791,13 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
 
                                     // FIXME: Remove this scope when NLL lands
                                     {
-                                        let params =
-                                            &mut new_trait_path.segments.last_mut().unwrap().params;
+                                        let args =
+                                            &mut new_trait_path.segments.last_mut().unwrap().args;
 
-                                        match params {
+                                        match args {
                                             // Convert somethiung like '<T as Iterator::Item> = u8'
                                             // to 'T: Iterator<Item=u8>'
-                                            &mut PathParameters::AngleBracketed {
+                                            &mut GenericArgs::AngleBracketed {
                                                 ref mut bindings,
                                                 ..
                                             } => {
@@ -808,7 +806,7 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
                                                     ty: rhs,
                                                 });
                                             }
-                                            &mut PathParameters::Parenthesized { .. } => {
+                                            &mut GenericArgs::Parenthesized { .. } => {
                                                 existing_predicates.push(
                                                     WherePredicate::EqPredicate {
                                                         lhs: lhs.clone(),
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index f454136026f..793a8a7f110 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1607,7 +1607,7 @@ fn external_path(cx: &DocContext, name: &str, trait_did: Option<DefId>, has_self
         def: Def::Err,
         segments: vec![PathSegment {
             name: name.to_string(),
-            params: external_generic_args(cx, trait_did, has_self, bindings, substs)
+            args: external_generic_args(cx, trait_did, has_self, bindings, substs)
         }],
     }
 }
@@ -2656,7 +2656,7 @@ impl Type {
         match *self {
             ResolvedPath { ref path, .. } => {
                 path.segments.last().and_then(|seg| {
-                    if let GenericArgs::AngleBracketed { ref types, .. } = seg.params {
+                    if let GenericArgs::AngleBracketed { ref types, .. } = seg.args {
                         Some(&**types)
                     } else {
                         None
@@ -2851,7 +2851,7 @@ impl Clean<Type> for hir::Ty {
                     let provided_params = &path.segments.last().unwrap();
                     let mut ty_substs = FxHashMap();
                     let mut lt_substs = FxHashMap();
-                    provided_params.with_parameters(|provided_params| {
+                    provided_params.with_args(|provided_params| {
                         let mut indices = GenericParamCount {
                             lifetimes: 0,
                             types: 0
@@ -2859,8 +2859,8 @@ impl Clean<Type> for hir::Ty {
                         for param in generics.params.iter() {
                             match param {
                                 hir::GenericParam::Lifetime(lt_param) => {
-                                    if let Some(lt) = provided_params.lifetimes
-                                        .get(indices.lifetimes).cloned() {
+                                    if let Some(lt) = provided_params.lifetimes()
+                                        .nth(indices.lifetimes).cloned() {
                                         if !lt.is_elided() {
                                             let lt_def_id =
                                                 cx.tcx.hir.local_def_id(lt_param.lifetime.id);
@@ -2872,8 +2872,8 @@ impl Clean<Type> for hir::Ty {
                                 hir::GenericParam::Type(ty_param) => {
                                     let ty_param_def =
                                         Def::TyParam(cx.tcx.hir.local_def_id(ty_param.id));
-                                    if let Some(ty) = provided_params.types
-                                        .get(indices.types).cloned() {
+                                    if let Some(ty) = provided_params.types()
+                                        .nth(indices.types).cloned() {
                                         ty_substs.insert(ty_param_def, ty.into_inner().clean(cx));
                                     } else if let Some(default) = ty_param.default.clone() {
                                         ty_substs.insert(ty_param_def,
@@ -3447,7 +3447,7 @@ impl Path {
             def: Def::Err,
             segments: vec![PathSegment {
                 name,
-                params: GenericArgs::AngleBracketed {
+                args: GenericArgs::AngleBracketed {
                     lifetimes: Vec::new(),
                     types: Vec::new(),
                     bindings: Vec::new(),
@@ -3471,7 +3471,7 @@ impl Clean<Path> for hir::Path {
     }
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eg, Debug, Hash)]
+#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Debug, Hash)]
 pub enum GenericArgs {
     AngleBracketed {
         lifetimes: Vec<Lifetime>,
@@ -3509,14 +3509,14 @@ impl Clean<GenericArgs> for hir::GenericArgs {
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Debug, Hash)]
 pub struct PathSegment {
     pub name: String,
-    pub params: GenericArgs,
+    pub args: GenericArgs,
 }
 
 impl Clean<PathSegment> for hir::PathSegment {
     fn clean(&self, cx: &DocContext) -> PathSegment {
         PathSegment {
             name: self.name.clean(cx),
-            params: self.with_parameters(|parameters| parameters.clean(cx))
+            args: self.with_args(|args| args.clean(cx))
         }
     }
 }
@@ -3550,7 +3550,7 @@ fn strip_path(path: &Path) -> Path {
     let segments = path.segments.iter().map(|s| {
         PathSegment {
             name: s.name.clone(),
-            params: PathParameters::AngleBracketed {
+            args: GenericArgs::AngleBracketed {
                 lifetimes: Vec::new(),
                 types: Vec::new(),
                 bindings: Vec::new(),
@@ -4365,7 +4365,7 @@ where F: Fn(DefId) -> Def {
         def: def_ctor(def_id),
         segments: hir::HirVec::from_vec(apb.names.iter().map(|s| hir::PathSegment {
             name: ast::Name::intern(&s),
-            parameters: None,
+            args: None,
             infer_types: false,
         }).collect())
     }
diff --git a/src/librustdoc/clean/simplify.rs b/src/librustdoc/clean/simplify.rs
index 1dd57465996..ac1952a4bab 100644
--- a/src/librustdoc/clean/simplify.rs
+++ b/src/librustdoc/clean/simplify.rs
@@ -97,7 +97,7 @@ pub fn where_clauses(cx: &DocContext, clauses: Vec<WP>) -> Vec<WP> {
                 return false
             }
             let last = path.segments.last_mut().unwrap();
-            match last.params {
+            match last.args {
                 PP::AngleBracketed { ref mut bindings, .. } => {
                     bindings.push(clean::TypeBinding {
                         name: name.clone(),
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index de5c0eeffc9..d2d068e5209 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -369,9 +369,9 @@ impl fmt::Display for clean::PathSegment {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.write_str(&self.name)?;
         if f.alternate() {
-            write!(f, "{:#}", self.params)
+            write!(f, "{:#}", self.args)
         } else {
-            write!(f, "{}", self.params)
+            write!(f, "{}", self.args)
         }
     }
 }
@@ -447,7 +447,7 @@ fn resolved_path(w: &mut fmt::Formatter, did: DefId, path: &clean::Path,
         }
     }
     if w.alternate() {
-        write!(w, "{:#}{:#}", HRef::new(did, &last.name), last.params)?;
+        write!(w, "{:#}{:#}", HRef::new(did, &last.name), last.args)?;
     } else {
         let path = if use_absolute {
             match href(did) {
@@ -461,7 +461,7 @@ fn resolved_path(w: &mut fmt::Formatter, did: DefId, path: &clean::Path,
         } else {
             format!("{}", HRef::new(did, &last.name))
         };
-        write!(w, "{}{}", path, last.params)?;
+        write!(w, "{}{}", path, last.args)?;
     }
     Ok(())
 }
@@ -757,7 +757,7 @@ fn fmt_impl(i: &clean::Impl,
                 clean::ResolvedPath { typarams: None, ref path, is_generic: false, .. } => {
                     let last = path.segments.last().unwrap();
                     fmt::Display::fmt(&last.name, f)?;
-                    fmt::Display::fmt(&last.params, f)?;
+                    fmt::Display::fmt(&last.args, f)?;
                 }
                 _ => unreachable!(),
             }
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 7bcaf9bbd52..7ff00123624 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -135,27 +135,27 @@ pub struct PathSegment {
     /// `Some` means that parameter list is supplied (`Path<X, Y>`)
     /// but it can be empty (`Path<>`).
     /// `P` is used as a size optimization for the common case with no parameters.
-    pub parameters: Option<P<GenericArgs>>,
+    pub args: Option<P<GenericArgs>>,
 }
 
 impl PathSegment {
     pub fn from_ident(ident: Ident) -> Self {
-        PathSegment { ident, parameters: None }
+        PathSegment { ident, args: None }
     }
     pub fn crate_root(span: Span) -> Self {
         PathSegment::from_ident(Ident::new(keywords::CrateRoot.name(), span))
     }
 }
 
-/// Parameters of a path segment.
+/// Arguments of a path segment.
 ///
 /// E.g. `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum GenericArgs {
     /// The `<'a, A,B,C>` in `foo::bar::baz::<'a, A,B,C>`
-    AngleBracketed(AngleBracketedParameterData),
+    AngleBracketed(AngleBracketedArgs),
     /// The `(A,B)` and `C` in `Foo(A,B) -> C`
-    Parenthesized(ParenthesizedParameterData),
+    Parenthesized(ParenthesizedArgData),
 }
 
 impl GenericArgs {
@@ -168,28 +168,28 @@ impl GenericArgs {
 }
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
-pub enum AngleBracketedParam {
+pub enum GenericArg {
     Lifetime(Lifetime),
     Type(P<Ty>),
 }
 
 /// A path like `Foo<'a, T>`
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Default)]
-pub struct AngleBracketedParameterData {
+pub struct AngleBracketedArgs {
     /// Overall span
     pub span: Span,
-    /// The parameters for this path segment.
-    pub parameters: Vec<AngleBracketedParam>,
+    /// The arguments for this path segment.
+    pub args: Vec<GenericArg>,
     /// Bindings (equality constraints) on associated types, if present.
     ///
     /// E.g., `Foo<A=Bar>`.
     pub bindings: Vec<TypeBinding>,
 }
 
-impl AngleBracketedParameterData {
+impl AngleBracketedArgs {
     pub fn lifetimes(&self) -> impl DoubleEndedIterator<Item = &Lifetime> {
-        self.parameters.iter().filter_map(|p| {
-            if let AngleBracketedParam::Lifetime(lt) = p {
+        self.args.iter().filter_map(|p| {
+            if let GenericArg::Lifetime(lt) = p {
                 Some(lt)
             } else {
                 None
@@ -198,8 +198,8 @@ impl AngleBracketedParameterData {
     }
 
     pub fn types(&self) -> impl DoubleEndedIterator<Item = &P<Ty>> {
-        self.parameters.iter().filter_map(|p| {
-            if let AngleBracketedParam::Type(ty) = p {
+        self.args.iter().filter_map(|p| {
+            if let GenericArg::Type(ty) = p {
                 Some(ty)
             } else {
                 None
@@ -208,13 +208,13 @@ impl AngleBracketedParameterData {
     }
 }
 
-impl Into<Option<P<GenericArgs>>> for AngleBracketedParameterData {
+impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
     fn into(self) -> Option<P<GenericArgs>> {
         Some(P(GenericArgs::AngleBracketed(self)))
     }
 }
 
-impl Into<Option<P<GenericArgs>>> for ParenthesizedParameterData {
+impl Into<Option<P<GenericArgs>>> for ParenthesizedArgData {
     fn into(self) -> Option<P<GenericArgs>> {
         Some(P(GenericArgs::Parenthesized(self)))
     }
@@ -222,7 +222,7 @@ impl Into<Option<P<GenericArgs>>> for ParenthesizedParameterData {
 
 /// A path like `Foo(A,B) -> C`
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
-pub struct ParenthesizedParameterData {
+pub struct ParenthesizedArgData {
     /// Overall span
     pub span: Span,
 
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index a59e34580c0..05a345fb2a1 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -31,7 +31,7 @@ pub trait AstBuilder {
     fn path_all(&self, sp: Span,
                 global: bool,
                 idents: Vec<ast::Ident>,
-                parameters: Vec<ast::AngleBracketedParam>,
+                parameters: Vec<ast::GenericArg>,
                 bindings: Vec<ast::TypeBinding>)
         -> ast::Path;
 
@@ -42,7 +42,7 @@ pub trait AstBuilder {
     fn qpath_all(&self, self_type: P<ast::Ty>,
                 trait_path: ast::Path,
                 ident: ast::Ident,
-                parameters: Vec<ast::AngleBracketedParam>,
+                parameters: Vec<ast::GenericArg>,
                 bindings: Vec<ast::TypeBinding>)
                 -> (ast::QSelf, ast::Path);
 
@@ -314,7 +314,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
                 span: Span,
                 global: bool,
                 mut idents: Vec<ast::Ident> ,
-                parameters: Vec<ast::AngleBracketedParam>,
+                args: Vec<ast::GenericArg>,
                 bindings: Vec<ast::TypeBinding> )
                 -> ast::Path {
         let last_ident = idents.pop().unwrap();
@@ -323,12 +323,12 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
         segments.extend(idents.into_iter().map(|ident| {
             ast::PathSegment::from_ident(ident.with_span_pos(span))
         }));
-        let parameters = if !parameters.is_empty() !bindings.is_empty() {
-            ast::AngleBracketedParameterData { parameters, bindings, span }.into()
+        let args = if !args.is_empty() || !bindings.is_empty() {
+            ast::AngleBracketedArgs { args, bindings, span }.into()
         } else {
             None
         };
-        segments.push(ast::PathSegment { ident: last_ident.with_span_pos(span), parameters });
+        segments.push(ast::PathSegment { ident: last_ident.with_span_pos(span), args });
         let mut path = ast::Path { span, segments };
         if global {
             if let Some(seg) = path.make_root() {
@@ -356,16 +356,16 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
                  self_type: P<ast::Ty>,
                  trait_path: ast::Path,
                  ident: ast::Ident,
-                 parameters: Vec<ast::AngleBracketedParam>,
+                 args: Vec<ast::GenericArg>,
                  bindings: Vec<ast::TypeBinding>)
                  -> (ast::QSelf, ast::Path) {
         let mut path = trait_path;
-        let parameters = if !parameters.is_empty() || !bindings.is_empty() {
-            ast::AngleBracketedParameterData { parameters, bindings, span: ident.span }.into()
+        let args = if !args.is_empty() || !bindings.is_empty() {
+            ast::AngleBracketedArgs { args, bindings, span: ident.span }.into()
         } else {
             None
         };
-        path.segments.push(ast::PathSegment { ident, parameters });
+        path.segments.push(ast::PathSegment { ident, args });
 
         (ast::QSelf {
             ty: self_type,
@@ -424,7 +424,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             self.path_all(DUMMY_SP,
                           true,
                           self.std_path(&["option", "Option"]),
-                          vec![ ast::AngleBracketedParam::Type(ty) ],
+                          vec![ ast::GenericArg::Type(ty) ],
                           Vec::new()))
     }
 
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index decb7e56132..dc23ed19d1b 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -132,11 +132,11 @@ pub trait Folder : Sized {
         noop_fold_exprs(es, self)
     }
 
-    fn fold_param(&mut self, p: AngleBracketedParam) -> AngleBracketedParam {
+    fn fold_param(&mut self, p: GenericArg) -> GenericArg {
         match p {
-            AngleBracketedParam::Lifetime(lt) =>
-                AngleBracketedParam::Lifetime(self.fold_lifetime(lt)),
-            AngleBracketedParam::Type(ty) => AngleBracketedParam::Type(self.fold_ty(ty)),
+            GenericArg::Lifetime(lt) =>
+                GenericArg::Lifetime(self.fold_lifetime(lt)),
+            GenericArg::Type(ty) => GenericArg::Type(self.fold_ty(ty)),
         }
     }
 
@@ -184,14 +184,14 @@ pub trait Folder : Sized {
         noop_fold_generic_args(p, self)
     }
 
-    fn fold_angle_bracketed_parameter_data(&mut self, p: AngleBracketedParameterData)
-                                           -> AngleBracketedParameterData
+    fn fold_angle_bracketed_parameter_data(&mut self, p: AngleBracketedArgs)
+                                           -> AngleBracketedArgs
     {
         noop_fold_angle_bracketed_parameter_data(p, self)
     }
 
-    fn fold_parenthesized_parameter_data(&mut self, p: ParenthesizedParameterData)
-                                         -> ParenthesizedParameterData
+    fn fold_parenthesized_parameter_data(&mut self, p: ParenthesizedArgData)
+                                         -> ParenthesizedArgData
     {
         noop_fold_parenthesized_parameter_data(p, self)
     }
@@ -441,9 +441,9 @@ pub fn noop_fold_usize<T: Folder>(i: usize, _: &mut T) -> usize {
 
 pub fn noop_fold_path<T: Folder>(Path { segments, span }: Path, fld: &mut T) -> Path {
     Path {
-        segments: segments.move_map(|PathSegment {ident, parameters}| PathSegment {
+        segments: segments.move_map(|PathSegment {ident, args}| PathSegment {
             ident: fld.fold_ident(ident),
-            parameters: parameters.map(|ps| ps.map(|ps| fld.fold_generic_args(ps))),
+            args: args.map(|ps| ps.map(|ps| fld.fold_generic_args(ps))),
         }),
         span: fld.new_span(span)
     }
@@ -473,22 +473,22 @@ pub fn noop_fold_generic_args<T: Folder>(generic_args: GenericArgs, fld: &mut T)
     }
 }
 
-pub fn noop_fold_angle_bracketed_parameter_data<T: Folder>(data: AngleBracketedParameterData,
+pub fn noop_fold_angle_bracketed_parameter_data<T: Folder>(data: AngleBracketedArgs,
                                                            fld: &mut T)
-                                                           -> AngleBracketedParameterData
+                                                           -> AngleBracketedArgs
 {
-    let AngleBracketedParameterData { parameters, bindings, span } = data;
-    AngleBracketedParameterData { parameters: parameters.move_map(|p| fld.fold_param(p)),
+    let AngleBracketedArgs { args, bindings, span } = data;
+    AngleBracketedArgs { args: args.move_map(|p| fld.fold_param(p)),
                                   bindings: bindings.move_map(|b| fld.fold_ty_binding(b)),
                                   span: fld.new_span(span) }
 }
 
-pub fn noop_fold_parenthesized_parameter_data<T: Folder>(data: ParenthesizedParameterData,
+pub fn noop_fold_parenthesized_parameter_data<T: Folder>(data: ParenthesizedArgData,
                                                          fld: &mut T)
-                                                         -> ParenthesizedParameterData
+                                                         -> ParenthesizedArgData
 {
-    let ParenthesizedParameterData { inputs, output, span } = data;
-    ParenthesizedParameterData { inputs: inputs.move_map(|ty| fld.fold_ty(ty)),
+    let ParenthesizedArgData { inputs, output, span } = data;
+    ParenthesizedArgData { inputs: inputs.move_map(|ty| fld.fold_ty(ty)),
                                  output: output.map(|ty| fld.fold_ty(ty)),
                                  span: fld.new_span(span) }
 }
@@ -1191,7 +1191,7 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span, attrs}: Expr, folder: &mu
                 ExprKind::MethodCall(
                     PathSegment {
                         ident: folder.fold_ident(seg.ident),
-                        parameters: seg.parameters.map(|ps| {
+                        args: seg.args.map(|ps| {
                             ps.map(|ps| folder.fold_generic_args(ps))
                         }),
                     },
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index e54c5445fa2..a51b3bc0ae4 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use rustc_target::spec::abi::{self, Abi};
-use ast::{AngleBracketedParameterData, ParenthesizedParameterData, AttrStyle, BareFnTy};
+use ast::{AngleBracketedArgs, ParenthesizedArgData, AttrStyle, BareFnTy};
 use ast::{RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
 use ast::Unsafety;
 use ast::{Mod, AnonConst, Arg, Arm, Attribute, BindingMode, TraitItemKind};
@@ -22,7 +22,7 @@ use ast::{Expr, ExprKind, RangeLimits};
 use ast::{Field, FnDecl};
 use ast::{ForeignItem, ForeignItemKind, FunctionRetTy};
 use ast::GenericParam;
-use ast::AngleBracketedParam;
+use ast::GenericArg;
 use ast::{Ident, ImplItem, IsAuto, Item, ItemKind};
 use ast::{Label, Lifetime, LifetimeDef, Lit, LitKind};
 use ast::Local;
@@ -1895,7 +1895,7 @@ impl<'a> Parser<'a> {
                              -> PResult<'a, ast::Path> {
         maybe_whole!(self, NtPath, |path| {
             if style == PathStyle::Mod &&
-               path.segments.iter().any(|segment| segment.parameters.is_some()) {
+               path.segments.iter().any(|segment| segment.args.is_some()) {
                 self.diagnostic().span_err(path.span, "unexpected generic arguments in path");
             }
             path
@@ -1970,12 +1970,12 @@ impl<'a> Parser<'a> {
                                  .span_label(self.prev_span, "try removing `::`").emit();
             }
 
-            let parameters = if self.eat_lt() {
+            let args = if self.eat_lt() {
                 // `<'a, T, A = U>`
-                let (parameters, bindings) = self.parse_generic_args()?;
+                let (args, bindings) = self.parse_generic_args()?;
                 self.expect_gt()?;
                 let span = lo.to(self.prev_span);
-                AngleBracketedParameterData { parameters, bindings, span }.into()
+                AngleBracketedArgs { args, bindings, span }.into()
             } else {
                 // `(T, U) -> R`
                 self.bump(); // `(`
@@ -1991,10 +1991,10 @@ impl<'a> Parser<'a> {
                     None
                 };
                 let span = lo.to(self.prev_span);
-                ParenthesizedParameterData { inputs, output, span }.into()
+                ParenthesizedArgData { inputs, output, span }.into()
             };
 
-            PathSegment { ident, parameters }
+            PathSegment { ident, args }
         } else {
             // Generic arguments are not found.
             PathSegment::from_ident(ident)
@@ -2544,8 +2544,8 @@ impl<'a> Parser<'a> {
             }
             _ => {
                 // Field access `expr.f`
-                if let Some(parameters) = segment.parameters {
-                    self.span_err(parameters.span(),
+                if let Some(args) = segment.args {
+                    self.span_err(args.span(),
                                   "field expressions may not have generic arguments");
                 }
 
@@ -4938,15 +4938,15 @@ impl<'a> Parser<'a> {
     /// Parses (possibly empty) list of lifetime and type arguments and associated type bindings,
     /// possibly including trailing comma.
     fn parse_generic_args(&mut self)
-                          -> PResult<'a, (Vec<AngleBracketedParam>, Vec<TypeBinding>)> {
-        let mut parameters = Vec::new();
+                          -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> {
+        let mut args = Vec::new();
         let mut bindings = Vec::new();
         let mut seen_type = false;
         let mut seen_binding = false;
         loop {
             if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
                 // Parse lifetime argument.
-                parameters.push(AngleBracketedParam::Lifetime(self.expect_lifetime()));
+                args.push(GenericArg::Lifetime(self.expect_lifetime()));
                 if seen_type || seen_binding {
                     self.span_err(self.prev_span,
                         "lifetime parameters must be declared prior to type parameters");
@@ -4971,7 +4971,7 @@ impl<'a> Parser<'a> {
                     self.span_err(ty_param.span,
                         "type parameters must be declared prior to associated type bindings");
                 }
-                parameters.push(AngleBracketedParam::Type(ty_param));
+                args.push(GenericArg::Type(ty_param));
                 seen_type = true;
             } else {
                 break
@@ -4981,7 +4981,7 @@ impl<'a> Parser<'a> {
                 break
             }
         }
-        Ok((parameters, bindings))
+        Ok((args, bindings))
     }
 
     /// Parses an optional `where` clause and places it in `generics`.
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 287fe0b636f..3b487430c52 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -13,7 +13,7 @@ pub use self::AnnNode::*;
 use rustc_target::spec::abi::{self, Abi};
 use ast::{self, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
 use ast::{SelfKind, RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
-use ast::{Attribute, MacDelimiter, AngleBracketedParam};
+use ast::{Attribute, MacDelimiter, GenericArg};
 use util::parser::{self, AssocOp, Fixity};
 use attr;
 use codemap::{self, CodeMap};
@@ -1017,10 +1017,10 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_param(&mut self, param: &AngleBracketedParam) -> io::Result<()> {
+    pub fn print_param(&mut self, param: &GenericArg) -> io::Result<()> {
         match param {
-            AngleBracketedParam::Lifetime(lt) => self.print_lifetime(lt),
-            AngleBracketedParam::Type(ty) => self.print_type(ty),
+            GenericArg::Lifetime(lt) => self.print_lifetime(lt),
+            GenericArg::Type(ty) => self.print_type(ty),
         }
     }
 
@@ -1991,8 +1991,8 @@ impl<'a> State<'a> {
         self.print_expr_maybe_paren(&args[0], parser::PREC_POSTFIX)?;
         self.s.word(".")?;
         self.print_ident(segment.ident)?;
-        if let Some(ref parameters) = segment.parameters {
-            self.print_generic_args(parameters, true)?;
+        if let Some(ref args) = segment.args {
+            self.print_generic_args(args, true)?;
         }
         self.print_call_post(base_args)
     }
@@ -2435,8 +2435,8 @@ impl<'a> State<'a> {
         if segment.ident.name != keywords::CrateRoot.name() &&
            segment.ident.name != keywords::DollarCrate.name() {
             self.print_ident(segment.ident)?;
-            if let Some(ref parameters) = segment.parameters {
-                self.print_generic_args(parameters, colons_before_params)?;
+            if let Some(ref args) = segment.args {
+                self.print_generic_args(args, colons_before_params)?;
             }
         } else if segment.ident.name == keywords::DollarCrate.name() {
             self.print_dollar_crate(segment.ident.span.ctxt())?;
@@ -2462,14 +2462,14 @@ impl<'a> State<'a> {
         self.s.word("::")?;
         let item_segment = path.segments.last().unwrap();
         self.print_ident(item_segment.ident)?;
-        match item_segment.parameters {
-            Some(ref parameters) => self.print_generic_args(parameters, colons_before_params),
+        match item_segment.args {
+            Some(ref args) => self.print_generic_args(args, colons_before_params),
             None => Ok(()),
         }
     }
 
     fn print_generic_args(&mut self,
-                             parameters: &ast::GenericArgs,
+                             args: &ast::GenericArgs,
                              colons_before_params: bool)
                              -> io::Result<()>
     {
@@ -2477,13 +2477,13 @@ impl<'a> State<'a> {
             self.s.word("::")?
         }
 
-        match *parameters {
+        match *args {
             ast::GenericArgs::AngleBracketed(ref data) => {
                 self.s.word("<")?;
 
-                self.commasep(Inconsistent, &data.parameters, |s, p| s.print_param(p))?;
+                self.commasep(Inconsistent, &data.args, |s, p| s.print_param(p))?;
 
-                let mut comma = data.parameters.len() != 0;
+                let mut comma = data.args.len() != 0;
 
                 for binding in data.bindings.iter() {
                     if comma {
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 6dc61f3058a..906f1941cd6 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -131,10 +131,10 @@ pub trait Visitor<'ast>: Sized {
     fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
         walk_generic_args(self, path_span, generic_args)
     }
-    fn visit_angle_bracketed_param(&mut self, param: &'ast AngleBracketedParam) {
+    fn visit_angle_bracketed_param(&mut self, param: &'ast GenericArg) {
         match param {
-            AngleBracketedParam::Lifetime(lt) => self.visit_lifetime(lt),
-            AngleBracketedParam::Type(ty)     => self.visit_ty(ty),
+            GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
+            GenericArg::Type(ty)     => self.visit_ty(ty),
         }
     }
     fn visit_assoc_type_binding(&mut self, type_binding: &'ast TypeBinding) {
@@ -381,8 +381,8 @@ pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V,
                                              path_span: Span,
                                              segment: &'a PathSegment) {
     visitor.visit_ident(segment.ident);
-    if let Some(ref parameters) = segment.parameters {
-        visitor.visit_generic_args(path_span, parameters);
+    if let Some(ref args) = segment.args {
+        visitor.visit_generic_args(path_span, args);
     }
 }
 
@@ -393,7 +393,7 @@ pub fn walk_generic_args<'a, V>(visitor: &mut V,
 {
     match *generic_args {
         GenericArgs::AngleBracketed(ref data) => {
-            walk_list!(visitor, visit_angle_bracketed_param, &data.parameters);
+            walk_list!(visitor, visit_angle_bracketed_param, &data.args);
             walk_list!(visitor, visit_assoc_type_binding, &data.bindings);
         }
         GenericArgs::Parenthesized(ref data) => {
diff --git a/src/libsyntax_ext/deriving/clone.rs b/src/libsyntax_ext/deriving/clone.rs
index 2e0551b32f7..504c3f8e913 100644
--- a/src/libsyntax_ext/deriving/clone.rs
+++ b/src/libsyntax_ext/deriving/clone.rs
@@ -13,7 +13,7 @@ use deriving::generic::*;
 use deriving::generic::ty::*;
 
 use syntax::ast::{self, Expr, Generics, ItemKind, MetaItem, VariantData};
-use syntax::ast::AngleBracketedParam;
+use syntax::ast::GenericArg;
 use syntax::attr;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
@@ -124,7 +124,7 @@ fn cs_clone_shallow(name: &str,
         let span = span.with_ctxt(cx.backtrace());
         let assert_path = cx.path_all(span, true,
                                         cx.std_path(&["clone", helper_name]),
-                                        vec![AngleBracketedParam::Type(ty)], vec![]);
+                                        vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
     fn process_variant(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>, variant: &VariantData) {
diff --git a/src/libsyntax_ext/deriving/cmp/eq.rs b/src/libsyntax_ext/deriving/cmp/eq.rs
index 51ab9975ed9..00ab39032ac 100644
--- a/src/libsyntax_ext/deriving/cmp/eq.rs
+++ b/src/libsyntax_ext/deriving/cmp/eq.rs
@@ -12,7 +12,7 @@ use deriving::path_std;
 use deriving::generic::*;
 use deriving::generic::ty::*;
 
-use syntax::ast::{self, Expr, MetaItem, AngleBracketedParam};
+use syntax::ast::{self, Expr, MetaItem, GenericArg};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
@@ -62,7 +62,7 @@ fn cs_total_eq_assert(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure)
         let span = span.with_ctxt(cx.backtrace());
         let assert_path = cx.path_all(span, true,
                                         cx.std_path(&["cmp", helper_name]),
-                                        vec![AngleBracketedParam::Type(ty)], vec![]);
+                                        vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
     fn process_variant(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>, variant: &ast::VariantData) {
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index a7bb7ba025f..299c53f3101 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -193,7 +193,7 @@ use std::vec;
 
 use rustc_target::spec::abi::Abi;
 use syntax::ast::{self, BinOpKind, EnumDef, Expr, GenericParam, Generics, Ident, PatKind};
-use syntax::ast::{VariantData, AngleBracketedParam};
+use syntax::ast::{VariantData, GenericArg};
 use syntax::attr;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
@@ -683,9 +683,9 @@ impl<'a> TraitDef<'a> {
             .collect();
 
         let self_params = self_lifetimes.into_iter()
-                                        .map(|lt| AngleBracketedParam::Lifetime(lt))
+                                        .map(|lt| GenericArg::Lifetime(lt))
                                         .chain(self_ty_params.into_iter().map(|ty|
-                                            AngleBracketedParam::Type(ty)))
+                                            GenericArg::Type(ty)))
                                         .collect();
 
         // Create the type of `self`.
diff --git a/src/libsyntax_ext/deriving/generic/ty.rs b/src/libsyntax_ext/deriving/generic/ty.rs
index d6ee7759ae6..7e6dd5fad25 100644
--- a/src/libsyntax_ext/deriving/generic/ty.rs
+++ b/src/libsyntax_ext/deriving/generic/ty.rs
@@ -15,7 +15,7 @@ pub use self::PtrTy::*;
 pub use self::Ty::*;
 
 use syntax::ast;
-use syntax::ast::{Expr, GenericParam, Generics, Ident, SelfKind, AngleBracketedParam};
+use syntax::ast::{Expr, GenericParam, Generics, Ident, SelfKind, GenericArg};
 use syntax::ext::base::ExtCtxt;
 use syntax::ext::build::AstBuilder;
 use syntax::codemap::{respan, DUMMY_SP};
@@ -89,8 +89,8 @@ impl<'a> Path<'a> {
         let tys: Vec<P<ast::Ty>> =
             self.params.iter().map(|t| t.to_ty(cx, span, self_ty, self_generics)).collect();
         let params = lt.into_iter()
-                       .map(|lt| AngleBracketedParam::Lifetime(lt))
-                       .chain(tys.into_iter().map(|ty| AngleBracketedParam::Type(ty)))
+                       .map(|lt| GenericArg::Lifetime(lt))
+                       .chain(tys.into_iter().map(|ty| GenericArg::Type(ty)))
                        .collect();
 
         match self.kind {
@@ -206,9 +206,9 @@ impl<'a> Ty<'a> {
                     .collect();
 
                 let params = lifetimes.into_iter()
-                                      .map(|lt| AngleBracketedParam::Lifetime(lt))
+                                      .map(|lt| GenericArg::Lifetime(lt))
                                       .chain(ty_params.into_iter().map(|ty|
-                                            AngleBracketedParam::Type(ty)))
+                                            GenericArg::Type(ty)))
                                       .collect();
 
                 cx.path_all(span,
diff --git a/src/libsyntax_ext/env.rs b/src/libsyntax_ext/env.rs
index 78721d880fc..5c3080260cc 100644
--- a/src/libsyntax_ext/env.rs
+++ b/src/libsyntax_ext/env.rs
@@ -13,7 +13,7 @@
 // interface.
 //
 
-use syntax::ast::{self, Ident, AngleBracketedParam};
+use syntax::ast::{self, Ident, GenericArg};
 use syntax::ext::base::*;
 use syntax::ext::base;
 use syntax::ext::build::AstBuilder;
@@ -39,10 +39,10 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt,
             cx.expr_path(cx.path_all(sp,
                                      true,
                                      cx.std_path(&["option", "Option", "None"]),
-                                     vec![AngleBracketedParam::Type(cx.ty_rptr(sp,
+                                     vec![GenericArg::Type(cx.ty_rptr(sp,
                                                      cx.ty_ident(sp, Ident::from_str("str")),
                                                      Some(lt),
-                                                     ast::Mutability::Immutable)],
+                                                     ast::Mutability::Immutable))],
                                      Vec::new()))
         }
         Ok(s) => {