rustc: remove hir::fold.

6 files changed, 142 insertions, 1260 deletions

diff --git a/src/librustc/hir/fold.rs b/src/librustc/hir/fold.rs
deleted file mode 100644
index 57b5599bd1d..00000000000
--- a/src/librustc/hir/fold.rs
+++ /dev/null
@@ -1,1131 +0,0 @@
-// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! A Folder represents an HIR->HIR fold; it accepts a HIR piece,
-//! and returns a piece of the same type.
-
-use hir::*;
-use syntax::ast::{Name, NodeId, DUMMY_NODE_ID, Attribute, Attribute_};
-use syntax::ast::{NestedMetaItem, NestedMetaItemKind, MetaItem, MetaItemKind};
-use hir;
-use syntax_pos::Span;
-use syntax::codemap::{respan, Spanned};
-use syntax::ptr::P;
-use syntax::parse::token::keywords;
-use syntax::util::move_map::MoveMap;
-
-pub trait Folder : Sized {
-    // Any additions to this trait should happen in form
-    // of a call to a public `noop_*` function that only calls
-    // out to the folder again, not other `noop_*` functions.
-    //
-    // This is a necessary API workaround to the problem of not
-    // being able to call out to the super default method
-    // in an overridden default method.
-
-    fn fold_crate(&mut self, c: Crate) -> Crate {
-        noop_fold_crate(c, self)
-    }
-
-    fn fold_meta_items(&mut self, meta_items: HirVec<P<MetaItem>>) -> HirVec<P<MetaItem>> {
-        noop_fold_meta_items(meta_items, self)
-    }
-
-    fn fold_meta_list_item(&mut self, list_item: NestedMetaItem) -> NestedMetaItem {
-        noop_fold_meta_list_item(list_item, self)
-    }
-
-    fn fold_meta_item(&mut self, meta_item: P<MetaItem>) -> P<MetaItem> {
-        noop_fold_meta_item(meta_item, self)
-    }
-
-    fn fold_view_path(&mut self, view_path: P<ViewPath>) -> P<ViewPath> {
-        noop_fold_view_path(view_path, self)
-    }
-
-    fn fold_foreign_item(&mut self, ni: ForeignItem) -> ForeignItem {
-        noop_fold_foreign_item(ni, self)
-    }
-
-    fn fold_item(&mut self, i: Item) -> Item {
-        noop_fold_item(i, self)
-    }
-
-    fn fold_item_id(&mut self, i: ItemId) -> ItemId {
-        noop_fold_item_id(i, self)
-    }
-
-    fn fold_struct_field(&mut self, sf: StructField) -> StructField {
-        noop_fold_struct_field(sf, self)
-    }
-
-    fn fold_item_underscore(&mut self, i: Item_) -> Item_ {
-        noop_fold_item_underscore(i, self)
-    }
-
-    fn fold_trait_item(&mut self, i: TraitItem) -> TraitItem {
-        noop_fold_trait_item(i, self)
-    }
-
-    fn fold_impl_item(&mut self, i: ImplItem) -> ImplItem {
-        noop_fold_impl_item(i, self)
-    }
-
-    fn fold_fn_decl(&mut self, d: P<FnDecl>) -> P<FnDecl> {
-        noop_fold_fn_decl(d, self)
-    }
-
-    fn fold_block(&mut self, b: P<Block>) -> P<Block> {
-        noop_fold_block(b, self)
-    }
-
-    fn fold_stmt(&mut self, s: Stmt) -> Stmt {
-        noop_fold_stmt(s, self)
-    }
-
-    fn fold_arm(&mut self, a: Arm) -> Arm {
-        noop_fold_arm(a, self)
-    }
-
-    fn fold_pat(&mut self, p: P<Pat>) -> P<Pat> {
-        noop_fold_pat(p, self)
-    }
-
-    fn fold_decl(&mut self, d: P<Decl>) -> P<Decl> {
-        noop_fold_decl(d, self)
-    }
-
-    fn fold_expr(&mut self, e: P<Expr>) -> P<Expr> {
-        e.map(|e| noop_fold_expr(e, self))
-    }
-
-    fn fold_ty(&mut self, t: P<Ty>) -> P<Ty> {
-        noop_fold_ty(t, self)
-    }
-
-    fn fold_ty_binding(&mut self, t: TypeBinding) -> TypeBinding {
-        noop_fold_ty_binding(t, self)
-    }
-
-    fn fold_mod(&mut self, m: Mod) -> Mod {
-        noop_fold_mod(m, self)
-    }
-
-    fn fold_foreign_mod(&mut self, nm: ForeignMod) -> ForeignMod {
-        noop_fold_foreign_mod(nm, self)
-    }
-
-    fn fold_variant(&mut self, v: Variant) -> Variant {
-        noop_fold_variant(v, self)
-    }
-
-    fn fold_name(&mut self, n: Name) -> Name {
-        noop_fold_name(n, self)
-    }
-
-    fn fold_usize(&mut self, i: usize) -> usize {
-        noop_fold_usize(i, self)
-    }
-
-    fn fold_path(&mut self, p: Path) -> Path {
-        noop_fold_path(p, self)
-    }
-
-    fn fold_path_parameters(&mut self, p: PathParameters) -> PathParameters {
-        noop_fold_path_parameters(p, self)
-    }
-
-    fn fold_angle_bracketed_parameter_data(&mut self,
-                                           p: AngleBracketedParameterData)
-                                           -> AngleBracketedParameterData {
-        noop_fold_angle_bracketed_parameter_data(p, self)
-    }
-
-    fn fold_parenthesized_parameter_data(&mut self,
-                                         p: ParenthesizedParameterData)
-                                         -> ParenthesizedParameterData {
-        noop_fold_parenthesized_parameter_data(p, self)
-    }
-
-    fn fold_local(&mut self, l: P<Local>) -> P<Local> {
-        noop_fold_local(l, self)
-    }
-
-    fn fold_lifetime(&mut self, l: Lifetime) -> Lifetime {
-        noop_fold_lifetime(l, self)
-    }
-
-    fn fold_lifetime_def(&mut self, l: LifetimeDef) -> LifetimeDef {
-        noop_fold_lifetime_def(l, self)
-    }
-
-    fn fold_attribute(&mut self, at: Attribute) -> Option<Attribute> {
-        noop_fold_attribute(at, self)
-    }
-
-    fn fold_arg(&mut self, a: Arg) -> Arg {
-        noop_fold_arg(a, self)
-    }
-
-    fn fold_generics(&mut self, generics: Generics) -> Generics {
-        noop_fold_generics(generics, self)
-    }
-
-    fn fold_trait_ref(&mut self, p: TraitRef) -> TraitRef {
-        noop_fold_trait_ref(p, self)
-    }
-
-    fn fold_poly_trait_ref(&mut self, p: PolyTraitRef) -> PolyTraitRef {
-        noop_fold_poly_trait_ref(p, self)
-    }
-
-    fn fold_variant_data(&mut self, vdata: VariantData) -> VariantData {
-        noop_fold_variant_data(vdata, self)
-    }
-
-    fn fold_lifetimes(&mut self, lts: HirVec<Lifetime>) -> HirVec<Lifetime> {
-        noop_fold_lifetimes(lts, self)
-    }
-
-    fn fold_lifetime_defs(&mut self, lts: HirVec<LifetimeDef>) -> HirVec<LifetimeDef> {
-        noop_fold_lifetime_defs(lts, self)
-    }
-
-    fn fold_ty_param(&mut self, tp: TyParam) -> TyParam {
-        noop_fold_ty_param(tp, self)
-    }
-
-    fn fold_ty_params(&mut self, tps: HirVec<TyParam>) -> HirVec<TyParam> {
-        noop_fold_ty_params(tps, self)
-    }
-
-    fn fold_opt_lifetime(&mut self, o_lt: Option<Lifetime>) -> Option<Lifetime> {
-        noop_fold_opt_lifetime(o_lt, self)
-    }
-
-    fn fold_opt_bounds(&mut self,
-                       b: Option<TyParamBounds>)
-                       -> Option<TyParamBounds> {
-        noop_fold_opt_bounds(b, self)
-    }
-
-    fn fold_bounds(&mut self, b: TyParamBounds) -> TyParamBounds {
-        noop_fold_bounds(b, self)
-    }
-
-    fn fold_ty_param_bound(&mut self, tpb: TyParamBound) -> TyParamBound {
-        noop_fold_ty_param_bound(tpb, self)
-    }
-
-    fn fold_mt(&mut self, mt: MutTy) -> MutTy {
-        noop_fold_mt(mt, self)
-    }
-
-    fn fold_field(&mut self, field: Field) -> Field {
-        noop_fold_field(field, self)
-    }
-
-    fn fold_where_clause(&mut self, where_clause: WhereClause) -> WhereClause {
-        noop_fold_where_clause(where_clause, self)
-    }
-
-    fn fold_where_predicate(&mut self, where_predicate: WherePredicate) -> WherePredicate {
-        noop_fold_where_predicate(where_predicate, self)
-    }
-
-    /// called for the `id` on each declaration
-    fn new_id(&mut self, i: NodeId) -> NodeId {
-        i
-    }
-
-    /// called for ids that are references (e.g., ItemDef)
-    fn map_id(&mut self, i: NodeId) -> NodeId {
-        i
-    }
-
-    fn new_span(&mut self, sp: Span) -> Span {
-        sp
-    }
-}
-
-pub fn noop_fold_meta_items<T: Folder>(meta_items: HirVec<P<MetaItem>>,
-                                       fld: &mut T)
-                                       -> HirVec<P<MetaItem>> {
-    meta_items.move_map(|x| fld.fold_meta_item(x))
-}
-
-pub fn noop_fold_view_path<T: Folder>(view_path: P<ViewPath>, fld: &mut T) -> P<ViewPath> {
-    view_path.map(|Spanned { node, span }| {
-        Spanned {
-            node: match node {
-                ViewPathSimple(name, path) => {
-                    ViewPathSimple(name, fld.fold_path(path))
-                }
-                ViewPathGlob(path) => {
-                    ViewPathGlob(fld.fold_path(path))
-                }
-                ViewPathList(path, path_list_idents) => {
-                    ViewPathList(fld.fold_path(path),
-                                 path_list_idents.move_map(|path_list_ident| {
-                                     Spanned {
-                                         node: PathListItem_ {
-                                             id: fld.new_id(path_list_ident.node.id),
-                                             name: path_list_ident.node.name,
-                                             rename: path_list_ident.node.rename,
-                                         },
-                                         span: fld.new_span(path_list_ident.span),
-                                     }
-                                 }))
-                }
-            },
-            span: fld.new_span(span),
-        }
-    })
-}
-
-pub fn fold_attrs<T, F>(attrs: T, fld: &mut F) -> T
-    where T: Into<Vec<Attribute>> + From<Vec<Attribute>>,
-          F: Folder,
-{
-    attrs.into().move_flat_map(|x| fld.fold_attribute(x)).into()
-}
-
-pub fn noop_fold_arm<T: Folder>(Arm { attrs, pats, guard, body }: Arm, fld: &mut T) -> Arm {
-    Arm {
-        attrs: fold_attrs(attrs, fld),
-        pats: pats.move_map(|x| fld.fold_pat(x)),
-        guard: guard.map(|x| fld.fold_expr(x)),
-        body: fld.fold_expr(body),
-    }
-}
-
-pub fn noop_fold_decl<T: Folder>(d: P<Decl>, fld: &mut T) -> P<Decl> {
-    d.map(|Spanned { node, span }| {
-        match node {
-            DeclLocal(l) => Spanned {
-                node: DeclLocal(fld.fold_local(l)),
-                span: fld.new_span(span),
-            },
-            DeclItem(it) => Spanned {
-                node: DeclItem(fld.fold_item_id(it)),
-                span: fld.new_span(span),
-            },
-        }
-    })
-}
-
-pub fn noop_fold_ty_binding<T: Folder>(b: TypeBinding, fld: &mut T) -> TypeBinding {
-    TypeBinding {
-        id: fld.new_id(b.id),
-        name: b.name,
-        ty: fld.fold_ty(b.ty),
-        span: fld.new_span(b.span),
-    }
-}
-
-pub fn noop_fold_ty<T: Folder>(t: P<Ty>, fld: &mut T) -> P<Ty> {
-    t.map(|Ty { id, node, span }| {
-        Ty {
-            id: fld.new_id(id),
-            node: match node {
-                TyInfer => node,
-                TyVec(ty) => TyVec(fld.fold_ty(ty)),
-                TyPtr(mt) => TyPtr(fld.fold_mt(mt)),
-                TyRptr(region, mt) => {
-                    TyRptr(fld.fold_opt_lifetime(region), fld.fold_mt(mt))
-                }
-                TyBareFn(f) => {
-                    TyBareFn(f.map(|BareFnTy { lifetimes, unsafety, abi, decl }| {
-                        BareFnTy {
-                            lifetimes: fld.fold_lifetime_defs(lifetimes),
-                            unsafety: unsafety,
-                            abi: abi,
-                            decl: fld.fold_fn_decl(decl),
-                        }
-                    }))
-                }
-                TyNever => node,
-                TyTup(tys) => TyTup(tys.move_map(|ty| fld.fold_ty(ty))),
-                TyPath(qself, path) => {
-                    let qself = qself.map(|QSelf { ty, position }| {
-                        QSelf {
-                            ty: fld.fold_ty(ty),
-                            position: position,
-                        }
-                    });
-                    TyPath(qself, fld.fold_path(path))
-                }
-                TyObjectSum(ty, bounds) => {
-                    TyObjectSum(fld.fold_ty(ty), fld.fold_bounds(bounds))
-                }
-                TyFixedLengthVec(ty, e) => {
-                    TyFixedLengthVec(fld.fold_ty(ty), fld.fold_expr(e))
-                }
-                TyTypeof(expr) => {
-                    TyTypeof(fld.fold_expr(expr))
-                }
-                TyPolyTraitRef(bounds) => {
-                    TyPolyTraitRef(bounds.move_map(|b| fld.fold_ty_param_bound(b)))
-                }
-                TyImplTrait(bounds) => {
-                    TyImplTrait(bounds.move_map(|b| fld.fold_ty_param_bound(b)))
-                }
-            },
-            span: fld.new_span(span),
-        }
-    })
-}
-
-pub fn noop_fold_foreign_mod<T: Folder>(ForeignMod { abi, items }: ForeignMod,
-                                        fld: &mut T)
-                                        -> ForeignMod {
-    ForeignMod {
-        abi: abi,
-        items: items.move_map(|x| fld.fold_foreign_item(x)),
-    }
-}
-
-pub fn noop_fold_variant<T: Folder>(v: Variant, fld: &mut T) -> Variant {
-    Spanned {
-        node: Variant_ {
-            name: v.node.name,
-            attrs: fold_attrs(v.node.attrs, fld),
-            data: fld.fold_variant_data(v.node.data),
-            disr_expr: v.node.disr_expr.map(|e| fld.fold_expr(e)),
-        },
-        span: fld.new_span(v.span),
-    }
-}
-
-pub fn noop_fold_name<T: Folder>(n: Name, _: &mut T) -> Name {
-    n
-}
-
-pub fn noop_fold_usize<T: Folder>(i: usize, _: &mut T) -> usize {
-    i
-}
-
-pub fn noop_fold_path<T: Folder>(Path { global, segments, span }: Path, fld: &mut T) -> Path {
-    Path {
-        global: global,
-        segments: segments.move_map(|PathSegment { name, parameters }| {
-            PathSegment {
-                name: fld.fold_name(name),
-                parameters: fld.fold_path_parameters(parameters),
-            }
-        }),
-        span: fld.new_span(span),
-    }
-}
-
-pub fn noop_fold_path_parameters<T: Folder>(path_parameters: PathParameters,
-                                            fld: &mut T)
-                                            -> PathParameters {
-    match path_parameters {
-        AngleBracketedParameters(data) =>
-            AngleBracketedParameters(fld.fold_angle_bracketed_parameter_data(data)),
-        ParenthesizedParameters(data) =>
-            ParenthesizedParameters(fld.fold_parenthesized_parameter_data(data)),
-    }
-}
-
-pub fn noop_fold_angle_bracketed_parameter_data<T: Folder>(data: AngleBracketedParameterData,
-                                                           fld: &mut T)
-                                                           -> AngleBracketedParameterData {
-    let AngleBracketedParameterData { lifetimes, types, bindings } = data;
-    AngleBracketedParameterData {
-        lifetimes: fld.fold_lifetimes(lifetimes),
-        types: types.move_map(|ty| fld.fold_ty(ty)),
-        bindings: bindings.move_map(|b| fld.fold_ty_binding(b)),
-    }
-}
-
-pub fn noop_fold_parenthesized_parameter_data<T: Folder>(data: ParenthesizedParameterData,
-                                                         fld: &mut T)
-                                                         -> ParenthesizedParameterData {
-    let ParenthesizedParameterData { inputs, output, span } = data;
-    ParenthesizedParameterData {
-        inputs: inputs.move_map(|ty| fld.fold_ty(ty)),
-        output: output.map(|ty| fld.fold_ty(ty)),
-        span: fld.new_span(span),
-    }
-}
-
-pub fn noop_fold_local<T: Folder>(l: P<Local>, fld: &mut T) -> P<Local> {
-    l.map(|Local { id, pat, ty, init, span, attrs }| {
-        Local {
-            id: fld.new_id(id),
-            ty: ty.map(|t| fld.fold_ty(t)),
-            pat: fld.fold_pat(pat),
-            init: init.map(|e| fld.fold_expr(e)),
-            span: fld.new_span(span),
-            attrs: fold_attrs(attrs, fld),
-        }
-    })
-}
-
-pub fn noop_fold_attribute<T: Folder>(at: Attribute, fld: &mut T) -> Option<Attribute> {
-    let Spanned {node: Attribute_ {id, style, value, is_sugared_doc}, span} = at;
-    Some(Spanned {
-        node: Attribute_ {
-            id: id,
-            style: style,
-            value: fld.fold_meta_item(value),
-            is_sugared_doc: is_sugared_doc,
-        },
-        span: fld.new_span(span),
-    })
-}
-
-pub fn noop_fold_meta_list_item<T: Folder>(li: NestedMetaItem, fld: &mut T)
-    -> NestedMetaItem {
-    Spanned {
-        node: match li.node {
-            NestedMetaItemKind::MetaItem(mi) =>  {
-                NestedMetaItemKind::MetaItem(fld.fold_meta_item(mi))
-            },
-            NestedMetaItemKind::Literal(lit) => NestedMetaItemKind::Literal(lit)
-        },
-        span: fld.new_span(li.span)
-    }
-}
-
-pub fn noop_fold_meta_item<T: Folder>(mi: P<MetaItem>, fld: &mut T) -> P<MetaItem> {
-    mi.map(|Spanned { node, span }| {
-        Spanned {
-            node: match node {
-                MetaItemKind::Word(id) => MetaItemKind::Word(id),
-                MetaItemKind::List(id, mis) => {
-                    MetaItemKind::List(id, mis.move_map(|e| fld.fold_meta_list_item(e)))
-                }
-                MetaItemKind::NameValue(id, s) => MetaItemKind::NameValue(id, s),
-            },
-            span: fld.new_span(span),
-        }
-    })
-}
-
-pub fn noop_fold_arg<T: Folder>(Arg { id, pat, ty }: Arg, fld: &mut T) -> Arg {
-    Arg {
-        id: fld.new_id(id),
-        pat: fld.fold_pat(pat),
-        ty: fld.fold_ty(ty),
-    }
-}
-
-pub fn noop_fold_fn_decl<T: Folder>(decl: P<FnDecl>, fld: &mut T) -> P<FnDecl> {
-    decl.map(|FnDecl { inputs, output, variadic }| {
-        FnDecl {
-            inputs: inputs.move_map(|x| fld.fold_arg(x)),
-            output: match output {
-                Return(ty) => Return(fld.fold_ty(ty)),
-                DefaultReturn(span) => DefaultReturn(span),
-            },
-            variadic: variadic,
-        }
-    })
-}
-
-pub fn noop_fold_ty_param_bound<T>(tpb: TyParamBound, fld: &mut T) -> TyParamBound
-    where T: Folder
-{
-    match tpb {
-        TraitTyParamBound(ty, modifier) => TraitTyParamBound(fld.fold_poly_trait_ref(ty), modifier),
-        RegionTyParamBound(lifetime) => RegionTyParamBound(fld.fold_lifetime(lifetime)),
-    }
-}
-
-pub fn noop_fold_ty_param<T: Folder>(tp: TyParam, fld: &mut T) -> TyParam {
-    let TyParam {id, name, bounds, default, span} = tp;
-    TyParam {
-        id: fld.new_id(id),
-        name: name,
-        bounds: fld.fold_bounds(bounds),
-        default: default.map(|x| fld.fold_ty(x)),
-        span: span,
-    }
-}
-
-pub fn noop_fold_ty_params<T: Folder>(tps: HirVec<TyParam>,
-                                      fld: &mut T)
-                                      -> HirVec<TyParam> {
-    tps.move_map(|tp| fld.fold_ty_param(tp))
-}
-
-pub fn noop_fold_lifetime<T: Folder>(l: Lifetime, fld: &mut T) -> Lifetime {
-    Lifetime {
-        id: fld.new_id(l.id),
-        name: l.name,
-        span: fld.new_span(l.span),
-    }
-}
-
-pub fn noop_fold_lifetime_def<T: Folder>(l: LifetimeDef, fld: &mut T) -> LifetimeDef {
-    LifetimeDef {
-        lifetime: fld.fold_lifetime(l.lifetime),
-        bounds: fld.fold_lifetimes(l.bounds),
-    }
-}
-
-pub fn noop_fold_lifetimes<T: Folder>(lts: HirVec<Lifetime>, fld: &mut T) -> HirVec<Lifetime> {
-    lts.move_map(|l| fld.fold_lifetime(l))
-}
-
-pub fn noop_fold_lifetime_defs<T: Folder>(lts: HirVec<LifetimeDef>,
-                                          fld: &mut T)
-                                          -> HirVec<LifetimeDef> {
-    lts.move_map(|l| fld.fold_lifetime_def(l))
-}
-
-pub fn noop_fold_opt_lifetime<T: Folder>(o_lt: Option<Lifetime>, fld: &mut T) -> Option<Lifetime> {
-    o_lt.map(|lt| fld.fold_lifetime(lt))
-}
-
-pub fn noop_fold_generics<T: Folder>(Generics {ty_params, lifetimes, where_clause, span}: Generics,
-                                     fld: &mut T)
-                                     -> Generics {
-    Generics {
-        ty_params: fld.fold_ty_params(ty_params),
-        lifetimes: fld.fold_lifetime_defs(lifetimes),
-        where_clause: fld.fold_where_clause(where_clause),
-        span: fld.new_span(span),
-    }
-}
-
-pub fn noop_fold_where_clause<T: Folder>(WhereClause { id, predicates }: WhereClause,
-                                         fld: &mut T)
-                                         -> WhereClause {
-    WhereClause {
-        id: fld.new_id(id),
-        predicates: predicates.move_map(|predicate| fld.fold_where_predicate(predicate)),
-    }
-}
-
-pub fn noop_fold_where_predicate<T: Folder>(pred: WherePredicate, fld: &mut T) -> WherePredicate {
-    match pred {
-        hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate{bound_lifetimes,
-                                                                     bounded_ty,
-                                                                     bounds,
-                                                                     span}) => {
-            hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
-                bound_lifetimes: fld.fold_lifetime_defs(bound_lifetimes),
-                bounded_ty: fld.fold_ty(bounded_ty),
-                bounds: bounds.move_map(|x| fld.fold_ty_param_bound(x)),
-                span: fld.new_span(span),
-            })
-        }
-        hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate{lifetime,
-                                                                       bounds,
-                                                                       span}) => {
-            hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
-                span: fld.new_span(span),
-                lifetime: fld.fold_lifetime(lifetime),
-                bounds: bounds.move_map(|bound| fld.fold_lifetime(bound)),
-            })
-        }
-        hir::WherePredicate::EqPredicate(hir::WhereEqPredicate{id,
-                                                               path,
-                                                               ty,
-                                                               span}) => {
-            hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
-                id: fld.new_id(id),
-                path: fld.fold_path(path),
-                ty: fld.fold_ty(ty),
-                span: fld.new_span(span),
-            })
-        }
-    }
-}
-
-pub fn noop_fold_variant_data<T: Folder>(vdata: VariantData, fld: &mut T) -> VariantData {
-    match vdata {
-        VariantData::Struct(fields, id) => {
-            VariantData::Struct(fields.move_map(|f| fld.fold_struct_field(f)),
-                                fld.new_id(id))
-        }
-        VariantData::Tuple(fields, id) => {
-            VariantData::Tuple(fields.move_map(|f| fld.fold_struct_field(f)),
-                               fld.new_id(id))
-        }
-        VariantData::Unit(id) => VariantData::Unit(fld.new_id(id)),
-    }
-}
-
-pub fn noop_fold_trait_ref<T: Folder>(p: TraitRef, fld: &mut T) -> TraitRef {
-    let id = fld.new_id(p.ref_id);
-    let TraitRef {
-        path,
-        ref_id: _,
-    } = p;
-    hir::TraitRef {
-        path: fld.fold_path(path),
-        ref_id: id,
-    }
-}
-
-pub fn noop_fold_poly_trait_ref<T: Folder>(p: PolyTraitRef, fld: &mut T) -> PolyTraitRef {
-    hir::PolyTraitRef {
-        bound_lifetimes: fld.fold_lifetime_defs(p.bound_lifetimes),
-        trait_ref: fld.fold_trait_ref(p.trait_ref),
-        span: fld.new_span(p.span),
-    }
-}
-
-pub fn noop_fold_struct_field<T: Folder>(f: StructField, fld: &mut T) -> StructField {
-    StructField {
-        span: fld.new_span(f.span),
-        id: fld.new_id(f.id),
-        name: f.name,
-        vis: f.vis,
-        ty: fld.fold_ty(f.ty),
-        attrs: fold_attrs(f.attrs, fld),
-    }
-}
-
-pub fn noop_fold_field<T: Folder>(Field { name, expr, span }: Field, folder: &mut T) -> Field {
-    Field {
-        name: respan(folder.new_span(name.span), folder.fold_name(name.node)),
-        expr: folder.fold_expr(expr),
-        span: folder.new_span(span),
-    }
-}
-
-pub fn noop_fold_mt<T: Folder>(MutTy { ty, mutbl }: MutTy, folder: &mut T) -> MutTy {
-    MutTy {
-        ty: folder.fold_ty(ty),
-        mutbl: mutbl,
-    }
-}
-
-pub fn noop_fold_opt_bounds<T: Folder>(b: Option<TyParamBounds>,
-                                       folder: &mut T)
-                                       -> Option<TyParamBounds> {
-    b.map(|bounds| folder.fold_bounds(bounds))
-}
-
-fn noop_fold_bounds<T: Folder>(bounds: TyParamBounds, folder: &mut T) -> TyParamBounds {
-    bounds.move_map(|bound| folder.fold_ty_param_bound(bound))
-}
-
-pub fn noop_fold_block<T: Folder>(b: P<Block>, folder: &mut T) -> P<Block> {
-    b.map(|Block { id, stmts, expr, rules, span }| {
-        Block {
-            id: folder.new_id(id),
-            stmts: stmts.move_map(|s| folder.fold_stmt(s)),
-            expr: expr.map(|x| folder.fold_expr(x)),
-            rules: rules,
-            span: folder.new_span(span),
-        }
-    })
-}
-
-pub fn noop_fold_item_underscore<T: Folder>(i: Item_, folder: &mut T) -> Item_ {
-    match i {
-        ItemExternCrate(string) => ItemExternCrate(string),
-        ItemUse(view_path) => {
-            ItemUse(folder.fold_view_path(view_path))
-        }
-        ItemStatic(t, m, e) => {
-            ItemStatic(folder.fold_ty(t), m, folder.fold_expr(e))
-        }
-        ItemConst(t, e) => {
-            ItemConst(folder.fold_ty(t), folder.fold_expr(e))
-        }
-        ItemFn(decl, unsafety, constness, abi, generics, body) => {
-            ItemFn(folder.fold_fn_decl(decl),
-                   unsafety,
-                   constness,
-                   abi,
-                   folder.fold_generics(generics),
-                   folder.fold_block(body))
-        }
-        ItemMod(m) => ItemMod(folder.fold_mod(m)),
-        ItemForeignMod(nm) => ItemForeignMod(folder.fold_foreign_mod(nm)),
-        ItemTy(t, generics) => {
-            ItemTy(folder.fold_ty(t), folder.fold_generics(generics))
-        }
-        ItemEnum(enum_definition, generics) => {
-            ItemEnum(hir::EnumDef {
-                         variants: enum_definition.variants.move_map(|x| folder.fold_variant(x)),
-                     },
-                     folder.fold_generics(generics))
-        }
-        ItemStruct(struct_def, generics) => {
-            let struct_def = folder.fold_variant_data(struct_def);
-            ItemStruct(struct_def, folder.fold_generics(generics))
-        }
-        ItemUnion(struct_def, generics) => {
-            let struct_def = folder.fold_variant_data(struct_def);
-            ItemUnion(struct_def, folder.fold_generics(generics))
-        }
-        ItemDefaultImpl(unsafety, ref trait_ref) => {
-            ItemDefaultImpl(unsafety, folder.fold_trait_ref((*trait_ref).clone()))
-        }
-        ItemImpl(unsafety, polarity, generics, ifce, ty, impl_items) => {
-            let new_impl_items = impl_items
-                .move_map(|item| folder.fold_impl_item(item));
-            let ifce = match ifce {
-                None => None,
-                Some(ref trait_ref) => {
-                    Some(folder.fold_trait_ref((*trait_ref).clone()))
-                }
-            };
-            ItemImpl(unsafety,
-                     polarity,
-                     folder.fold_generics(generics),
-                     ifce,
-                     folder.fold_ty(ty),
-                     new_impl_items)
-        }
-        ItemTrait(unsafety, generics, bounds, items) => {
-            let bounds = folder.fold_bounds(bounds);
-            let items = items.move_map(|item| folder.fold_trait_item(item));
-            ItemTrait(unsafety, folder.fold_generics(generics), bounds, items)
-        }
-    }
-}
-
-pub fn noop_fold_trait_item<T: Folder>(i: TraitItem,
-                                       folder: &mut T)
-                                       -> TraitItem {
-    TraitItem {
-        id: folder.new_id(i.id),
-        name: folder.fold_name(i.name),
-        attrs: fold_attrs(i.attrs, folder),
-        node: match i.node {
-            ConstTraitItem(ty, default) => {
-                ConstTraitItem(folder.fold_ty(ty), default.map(|x| folder.fold_expr(x)))
-            }
-            MethodTraitItem(sig, body) => {
-                MethodTraitItem(noop_fold_method_sig(sig, folder),
-                                body.map(|x| folder.fold_block(x)))
-            }
-            TypeTraitItem(bounds, default) => {
-                TypeTraitItem(folder.fold_bounds(bounds),
-                              default.map(|x| folder.fold_ty(x)))
-            }
-        },
-        span: folder.new_span(i.span),
-    }
-}
-
-pub fn noop_fold_impl_item<T: Folder>(i: ImplItem, folder: &mut T) -> ImplItem {
-    ImplItem {
-        id: folder.new_id(i.id),
-        name: folder.fold_name(i.name),
-        attrs: fold_attrs(i.attrs, folder),
-        vis: i.vis,
-        defaultness: i.defaultness,
-        node: match i.node {
-            ImplItemKind::Const(ty, expr) => {
-                ImplItemKind::Const(folder.fold_ty(ty), folder.fold_expr(expr))
-            }
-            ImplItemKind::Method(sig, body) => {
-                ImplItemKind::Method(noop_fold_method_sig(sig, folder), folder.fold_block(body))
-            }
-            ImplItemKind::Type(ty) => ImplItemKind::Type(folder.fold_ty(ty)),
-        },
-        span: folder.new_span(i.span),
-    }
-}
-
-pub fn noop_fold_mod<T: Folder>(Mod { inner, item_ids }: Mod, folder: &mut T) -> Mod {
-    Mod {
-        inner: folder.new_span(inner),
-        item_ids: item_ids.move_map(|x| folder.fold_item_id(x)),
-    }
-}
-
-pub fn noop_fold_crate<T: Folder>(Crate { module, attrs, config, span,
-                                          exported_macros, items }: Crate,
-                                  folder: &mut T)
-                                  -> Crate {
-    let config = folder.fold_meta_items(config);
-
-    let crate_mod = folder.fold_item(hir::Item {
-        name: keywords::Invalid.name(),
-        attrs: attrs,
-        id: DUMMY_NODE_ID,
-        vis: hir::Public,
-        span: span,
-        node: hir::ItemMod(module),
-    });
-
-    let (module, attrs, span) = match crate_mod {
-        hir::Item { attrs, span, node, .. } => {
-            match node {
-                hir::ItemMod(m) => (m, attrs, span),
-                _ => panic!("fold converted a module to not a module"),
-            }
-        }
-    };
-
-    let items = items.into_iter()
-                     .map(|(id, item)| (id, folder.fold_item(item)))
-                     .collect();
-
-    Crate {
-        module: module,
-        attrs: attrs,
-        config: config,
-        span: span,
-        exported_macros: exported_macros,
-        items: items,
-    }
-}
-
-pub fn noop_fold_item_id<T: Folder>(i: ItemId, folder: &mut T) -> ItemId {
-    let id = folder.map_id(i.id);
-    ItemId { id: id }
-}
-
-// fold one item into one item
-pub fn noop_fold_item<T: Folder>(item: Item, folder: &mut T) -> Item {
-    let Item { id, name, attrs, node, vis, span } = item;
-    let id = folder.new_id(id);
-    let node = folder.fold_item_underscore(node);
-
-    Item {
-        id: id,
-        name: folder.fold_name(name),
-        attrs: fold_attrs(attrs, folder),
-        node: node,
-        vis: vis,
-        span: folder.new_span(span),
-    }
-}
-
-pub fn noop_fold_foreign_item<T: Folder>(ni: ForeignItem, folder: &mut T) -> ForeignItem {
-    ForeignItem {
-        id: folder.new_id(ni.id),
-        name: folder.fold_name(ni.name),
-        attrs: fold_attrs(ni.attrs, folder),
-        node: match ni.node {
-            ForeignItemFn(fdec, generics) => {
-                ForeignItemFn(folder.fold_fn_decl(fdec), folder.fold_generics(generics))
-            }
-            ForeignItemStatic(t, m) => {
-                ForeignItemStatic(folder.fold_ty(t), m)
-            }
-        },
-        vis: ni.vis,
-        span: folder.new_span(ni.span),
-    }
-}
-
-pub fn noop_fold_method_sig<T: Folder>(sig: MethodSig, folder: &mut T) -> MethodSig {
-    MethodSig {
-        generics: folder.fold_generics(sig.generics),
-        abi: sig.abi,
-        unsafety: sig.unsafety,
-        constness: sig.constness,
-        decl: folder.fold_fn_decl(sig.decl),
-    }
-}
-
-pub fn noop_fold_pat<T: Folder>(p: P<Pat>, folder: &mut T) -> P<Pat> {
-    p.map(|Pat { id, node, span }| {
-        Pat {
-            id: folder.new_id(id),
-            node: match node {
-                PatKind::Wild => PatKind::Wild,
-                PatKind::Binding(binding_mode, pth1, sub) => {
-                    PatKind::Binding(binding_mode,
-                             Spanned {
-                                 span: folder.new_span(pth1.span),
-                                 node: folder.fold_name(pth1.node),
-                             },
-                             sub.map(|x| folder.fold_pat(x)))
-                }
-                PatKind::Lit(e) => PatKind::Lit(folder.fold_expr(e)),
-                PatKind::TupleStruct(pth, pats, ddpos) => {
-                    PatKind::TupleStruct(folder.fold_path(pth),
-                            pats.move_map(|x| folder.fold_pat(x)), ddpos)
-                }
-                PatKind::Path(opt_qself, pth) => {
-                    let opt_qself = opt_qself.map(|qself| {
-                        QSelf { ty: folder.fold_ty(qself.ty), position: qself.position }
-                    });
-                    PatKind::Path(opt_qself, folder.fold_path(pth))
-                }
-                PatKind::Struct(pth, fields, etc) => {
-                    let pth = folder.fold_path(pth);
-                    let fs = fields.move_map(|f| {
-                        Spanned {
-                            span: folder.new_span(f.span),
-                            node: hir::FieldPat {
-                                name: f.node.name,
-                                pat: folder.fold_pat(f.node.pat),
-                                is_shorthand: f.node.is_shorthand,
-                            },
-                        }
-                    });
-                    PatKind::Struct(pth, fs, etc)
-                }
-                PatKind::Tuple(elts, ddpos) => {
-                    PatKind::Tuple(elts.move_map(|x| folder.fold_pat(x)), ddpos)
-                }
-                PatKind::Box(inner) => PatKind::Box(folder.fold_pat(inner)),
-                PatKind::Ref(inner, mutbl) => PatKind::Ref(folder.fold_pat(inner), mutbl),
-                PatKind::Range(e1, e2) => {
-                    PatKind::Range(folder.fold_expr(e1), folder.fold_expr(e2))
-                }
-                PatKind::Vec(before, slice, after) => {
-                    PatKind::Vec(before.move_map(|x| folder.fold_pat(x)),
-                           slice.map(|x| folder.fold_pat(x)),
-                           after.move_map(|x| folder.fold_pat(x)))
-                }
-            },
-            span: folder.new_span(span),
-        }
-    })
-}
-
-pub fn noop_fold_expr<T: Folder>(Expr { id, node, span, attrs }: Expr, folder: &mut T) -> Expr {
-    Expr {
-        id: folder.new_id(id),
-        node: match node {
-            ExprBox(e) => {
-                ExprBox(folder.fold_expr(e))
-            }
-            ExprVec(exprs) => {
-                ExprVec(exprs.move_map(|x| folder.fold_expr(x)))
-            }
-            ExprRepeat(expr, count) => {
-                ExprRepeat(folder.fold_expr(expr), folder.fold_expr(count))
-            }
-            ExprTup(elts) => ExprTup(elts.move_map(|x| folder.fold_expr(x))),
-            ExprCall(f, args) => {
-                ExprCall(folder.fold_expr(f), args.move_map(|x| folder.fold_expr(x)))
-            }
-            ExprMethodCall(name, tps, args) => {
-                ExprMethodCall(respan(folder.new_span(name.span), folder.fold_name(name.node)),
-                               tps.move_map(|x| folder.fold_ty(x)),
-                               args.move_map(|x| folder.fold_expr(x)))
-            }
-            ExprBinary(binop, lhs, rhs) => {
-                ExprBinary(binop, folder.fold_expr(lhs), folder.fold_expr(rhs))
-            }
-            ExprUnary(binop, ohs) => {
-                ExprUnary(binop, folder.fold_expr(ohs))
-            }
-            ExprLit(l) => ExprLit(l),
-            ExprCast(expr, ty) => {
-                ExprCast(folder.fold_expr(expr), folder.fold_ty(ty))
-            }
-            ExprType(expr, ty) => {
-                ExprType(folder.fold_expr(expr), folder.fold_ty(ty))
-            }
-            ExprAddrOf(m, ohs) => ExprAddrOf(m, folder.fold_expr(ohs)),
-            ExprIf(cond, tr, fl) => {
-                ExprIf(folder.fold_expr(cond),
-                       folder.fold_block(tr),
-                       fl.map(|x| folder.fold_expr(x)))
-            }
-            ExprWhile(cond, body, opt_name) => {
-                ExprWhile(folder.fold_expr(cond),
-                          folder.fold_block(body),
-                          opt_name.map(|label| {
-                              respan(folder.new_span(label.span), folder.fold_name(label.node))
-                          }))
-            }
-            ExprLoop(body, opt_name) => {
-                ExprLoop(folder.fold_block(body),
-                         opt_name.map(|label| {
-                             respan(folder.new_span(label.span), folder.fold_name(label.node))
-                         }))
-            }
-            ExprMatch(expr, arms, source) => {
-                ExprMatch(folder.fold_expr(expr),
-                          arms.move_map(|x| folder.fold_arm(x)),
-                          source)
-            }
-            ExprClosure(capture_clause, decl, body, fn_decl_span) => {
-                ExprClosure(capture_clause,
-                            folder.fold_fn_decl(decl),
-                            folder.fold_block(body),
-                            folder.new_span(fn_decl_span))
-            }
-            ExprBlock(blk) => ExprBlock(folder.fold_block(blk)),
-            ExprAssign(el, er) => {
-                ExprAssign(folder.fold_expr(el), folder.fold_expr(er))
-            }
-            ExprAssignOp(op, el, er) => {
-                ExprAssignOp(op, folder.fold_expr(el), folder.fold_expr(er))
-            }
-            ExprField(el, name) => {
-                ExprField(folder.fold_expr(el),
-                          respan(folder.new_span(name.span), folder.fold_name(name.node)))
-            }
-            ExprTupField(el, index) => {
-                ExprTupField(folder.fold_expr(el),
-                             respan(folder.new_span(index.span), folder.fold_usize(index.node)))
-            }
-            ExprIndex(el, er) => {
-                ExprIndex(folder.fold_expr(el), folder.fold_expr(er))
-            }
-            ExprPath(qself, path) => {
-                let qself = qself.map(|QSelf { ty, position }| {
-                    QSelf {
-                        ty: folder.fold_ty(ty),
-                        position: position,
-                    }
-                });
-                ExprPath(qself, folder.fold_path(path))
-            }
-            ExprBreak(opt_name) => ExprBreak(opt_name.map(|label| {
-                respan(folder.new_span(label.span), folder.fold_name(label.node))
-            })),
-            ExprAgain(opt_name) => ExprAgain(opt_name.map(|label| {
-                respan(folder.new_span(label.span), folder.fold_name(label.node))
-            })),
-            ExprRet(e) => ExprRet(e.map(|x| folder.fold_expr(x))),
-            ExprInlineAsm(asm, outputs, inputs) => {
-                ExprInlineAsm(asm,
-                              outputs.move_map(|x| folder.fold_expr(x)),
-                              inputs.move_map(|x| folder.fold_expr(x)))
-            }
-            ExprStruct(path, fields, maybe_expr) => {
-                ExprStruct(folder.fold_path(path),
-                           fields.move_map(|x| folder.fold_field(x)),
-                           maybe_expr.map(|x| folder.fold_expr(x)))
-            }
-        },
-        span: folder.new_span(span),
-        attrs: fold_attrs(attrs, folder),
-    }
-}
-
-pub fn noop_fold_stmt<T: Folder>(stmt: Stmt, folder: &mut T) -> Stmt {
-    let span = folder.new_span(stmt.span);
-    match stmt.node {
-        StmtDecl(d, id) => {
-            let id = folder.new_id(id);
-            Spanned {
-                node: StmtDecl(folder.fold_decl(d), id),
-                span: span
-            }
-        }
-        StmtExpr(e, id) => {
-            let id = folder.new_id(id);
-            Spanned {
-                node: StmtExpr(folder.fold_expr(e), id),
-                span: span,
-            }
-        }
-        StmtSemi(e, id) => {
-            let id = folder.new_id(id);
-            Spanned {
-                node: StmtSemi(folder.fold_expr(e), id),
-                span: span,
-            }
-        }
-    }
-}
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index e22c9869ab1..0cfdbae1a50 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -67,7 +67,6 @@ macro_rules! hir_vec {
 pub mod check_attr;
 pub mod def;
 pub mod def_id;
-pub mod fold;
 pub mod intravisit;
 pub mod lowering;
 pub mod map;
diff --git a/src/librustc_const_eval/check_match.rs b/src/librustc_const_eval/check_match.rs
index 5d2b266ec4b..dda72ce57b4 100644
--- a/src/librustc_const_eval/check_match.rs
+++ b/src/librustc_const_eval/check_match.rs
@@ -40,11 +40,10 @@ use rustc_back::slice;
 use syntax::ast::{self, DUMMY_NODE_ID, NodeId};
 use syntax::codemap::Spanned;
 use syntax_pos::{Span, DUMMY_SP};
-use rustc::hir::fold::{Folder, noop_fold_pat};
 use rustc::hir::print::pat_to_string;
 use syntax::ptr::P;
+use syntax::util::move_map::MoveMap;
 use rustc::util::common::ErrorReported;
-use rustc::util::nodemap::FnvHashMap;
 
 pub const DUMMY_WILD_PAT: &'static Pat = &Pat {
     id: DUMMY_NODE_ID,
@@ -182,7 +181,7 @@ fn check_expr(cx: &mut MatchCheckCtxt, ex: &hir::Expr) {
                 }
             }
 
-            let mut static_inliner = StaticInliner::new(cx.tcx, None);
+            let mut static_inliner = StaticInliner::new(cx.tcx);
             let inlined_arms = arms.iter().map(|arm| {
                 (arm.pats.iter().map(|pat| {
                     static_inliner.fold_pat((*pat).clone())
@@ -467,53 +466,30 @@ fn const_val_to_expr(value: &ConstVal) -> P<hir::Expr> {
     })
 }
 
-pub struct StaticInliner<'a, 'tcx: 'a> {
-    pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    pub failed: bool,
-    pub renaming_map: Option<&'a mut FnvHashMap<(NodeId, Span), NodeId>>,
+struct StaticInliner<'a, 'tcx: 'a> {
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
+    failed: bool
 }
 
 impl<'a, 'tcx> StaticInliner<'a, 'tcx> {
-    pub fn new<'b>(tcx: TyCtxt<'b, 'tcx, 'tcx>,
-                   renaming_map: Option<&'b mut FnvHashMap<(NodeId, Span), NodeId>>)
-                   -> StaticInliner<'b, 'tcx> {
+    pub fn new<'b>(tcx: TyCtxt<'b, 'tcx, 'tcx>) -> StaticInliner<'b, 'tcx> {
         StaticInliner {
             tcx: tcx,
-            failed: false,
-            renaming_map: renaming_map
+            failed: false
         }
     }
 }
 
-struct RenamingRecorder<'map> {
-    substituted_node_id: NodeId,
-    origin_span: Span,
-    renaming_map: &'map mut FnvHashMap<(NodeId, Span), NodeId>
-}
-
-impl<'v, 'map> Visitor<'v> for RenamingRecorder<'map> {
-    fn visit_id(&mut self, node_id: NodeId) {
-        let key = (node_id, self.origin_span);
-        self.renaming_map.insert(key, self.substituted_node_id);
-    }
-}
-
-impl<'a, 'tcx> Folder for StaticInliner<'a, 'tcx> {
+impl<'a, 'tcx> StaticInliner<'a, 'tcx> {
     fn fold_pat(&mut self, pat: P<Pat>) -> P<Pat> {
-        return match pat.node {
+        match pat.node {
             PatKind::Path(..) => {
                 match self.tcx.expect_def(pat.id) {
                     Def::AssociatedConst(did) | Def::Const(did) => {
                         let substs = Some(self.tcx.node_id_item_substs(pat.id).substs);
                         if let Some((const_expr, _)) = lookup_const_by_id(self.tcx, did, substs) {
                             match const_expr_to_pat(self.tcx, const_expr, pat.id, pat.span) {
-                                Ok(new_pat) => {
-                                    if let Some(ref mut map) = self.renaming_map {
-                                        // Record any renamings we do here
-                                        record_renamings(const_expr, &pat, map);
-                                    }
-                                    new_pat
-                                }
+                                Ok(new_pat) => return new_pat,
                                 Err(def_id) => {
                                     self.failed = true;
                                     self.tcx.sess.span_err(
@@ -521,33 +497,62 @@ impl<'a, 'tcx> Folder for StaticInliner<'a, 'tcx> {
                                         &format!("constants of the type `{}` \
                                                   cannot be used in patterns",
                                                  self.tcx.item_path_str(def_id)));
-                                    pat
                                 }
                             }
                         } else {
                             self.failed = true;
                             span_err!(self.tcx.sess, pat.span, E0158,
                                 "statics cannot be referenced in patterns");
-                            pat
                         }
                     }
-                    _ => noop_fold_pat(pat, self)
+                    _ => {}
                 }
             }
-            _ => noop_fold_pat(pat, self)
-        };
+            _ => {}
+        }
 
-        fn record_renamings(const_expr: &hir::Expr,
-                            substituted_pat: &hir::Pat,
-                            renaming_map: &mut FnvHashMap<(NodeId, Span), NodeId>) {
-            let mut renaming_recorder = RenamingRecorder {
-                substituted_node_id: substituted_pat.id,
-                origin_span: substituted_pat.span,
-                renaming_map: renaming_map,
+        pat.map(|Pat { id, node, span }| {
+            let node = match node {
+                PatKind::Binding(binding_mode, pth1, sub) => {
+                    PatKind::Binding(binding_mode, pth1, sub.map(|x| self.fold_pat(x)))
+                }
+                PatKind::TupleStruct(pth, pats, ddpos) => {
+                    PatKind::TupleStruct(pth, pats.move_map(|x| self.fold_pat(x)), ddpos)
+                }
+                PatKind::Struct(pth, fields, etc) => {
+                    let fs = fields.move_map(|f| {
+                        Spanned {
+                            span: f.span,
+                            node: hir::FieldPat {
+                                name: f.node.name,
+                                pat: self.fold_pat(f.node.pat),
+                                is_shorthand: f.node.is_shorthand,
+                            },
+                        }
+                    });
+                    PatKind::Struct(pth, fs, etc)
+                }
+                PatKind::Tuple(elts, ddpos) => {
+                    PatKind::Tuple(elts.move_map(|x| self.fold_pat(x)), ddpos)
+                }
+                PatKind::Box(inner) => PatKind::Box(self.fold_pat(inner)),
+                PatKind::Ref(inner, mutbl) => PatKind::Ref(self.fold_pat(inner), mutbl),
+                PatKind::Vec(before, slice, after) => {
+                    PatKind::Vec(before.move_map(|x| self.fold_pat(x)),
+                                 slice.map(|x| self.fold_pat(x)),
+                                 after.move_map(|x| self.fold_pat(x)))
+                }
+                PatKind::Wild |
+                PatKind::Lit(_) |
+                PatKind::Range(..) |
+                PatKind::Path(..) => node
             };
-
-            renaming_recorder.visit_expr(const_expr);
-        }
+            Pat {
+                id: id,
+                node: node,
+                span: span
+            }
+        })
     }
 }
 
@@ -1047,7 +1052,7 @@ pub fn specialize<'a, 'b, 'tcx>(
 fn check_local(cx: &mut MatchCheckCtxt, loc: &hir::Local) {
     intravisit::walk_local(cx, loc);
 
-    let pat = StaticInliner::new(cx.tcx, None).fold_pat(loc.pat.clone());
+    let pat = StaticInliner::new(cx.tcx).fold_pat(loc.pat.clone());
     check_irrefutable(cx, &pat, false);
 
     // Check legality of move bindings and `@` patterns.
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 3983c098f30..7eb7b24015e 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -38,7 +38,6 @@ use rustc::middle::privacy::AccessLevels;
 use rustc::middle::resolve_lifetime::DefRegion::*;
 use rustc::hir::def::Def;
 use rustc::hir::def_id::{self, DefId, DefIndex, CRATE_DEF_INDEX};
-use rustc::hir::fold::Folder;
 use rustc::hir::print as pprust;
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, AdtKind};
@@ -774,7 +773,20 @@ impl Lifetime {
 }
 
 impl Clean<Lifetime> for hir::Lifetime {
-    fn clean(&self, _: &DocContext) -> Lifetime {
+    fn clean(&self, cx: &DocContext) -> Lifetime {
+        if let Some(tcx) = cx.tcx_opt() {
+            let def = tcx.named_region_map.defs.get(&self.id).cloned();
+            match def {
+                Some(DefEarlyBoundRegion(_, node_id)) |
+                Some(DefLateBoundRegion(_, node_id)) |
+                Some(DefFreeRegion(_, node_id)) => {
+                    if let Some(lt) = cx.lt_substs.borrow().get(&node_id).cloned() {
+                        return lt;
+                    }
+                }
+                _ => {}
+            }
+        }
         Lifetime(self.name.to_string())
     }
 }
@@ -1629,42 +1641,6 @@ impl From<ast::FloatTy> for PrimitiveType {
     }
 }
 
-// Poor man's type parameter substitution at HIR level.
-// Used to replace private type aliases in public signatures with their aliased types.
-struct SubstAlias<'a, 'tcx: 'a> {
-    tcx: &'a ty::TyCtxt<'a, 'tcx, 'tcx>,
-    // Table type parameter definition -> substituted type
-    ty_substs: FnvHashMap<Def, hir::Ty>,
-    // Table node id of lifetime parameter definition -> substituted lifetime
-    lt_substs: FnvHashMap<ast::NodeId, hir::Lifetime>,
-}
-
-impl<'a, 'tcx: 'a, 'b: 'tcx> Folder for SubstAlias<'a, 'tcx> {
-    fn fold_ty(&mut self, ty: P<hir::Ty>) -> P<hir::Ty> {
-        if let hir::TyPath(..) = ty.node {
-            let def = self.tcx.expect_def(ty.id);
-            if let Some(new_ty) = self.ty_substs.get(&def).cloned() {
-                return P(new_ty);
-            }
-        }
-        hir::fold::noop_fold_ty(ty, self)
-    }
-    fn fold_lifetime(&mut self, lt: hir::Lifetime) -> hir::Lifetime {
-        let def = self.tcx.named_region_map.defs.get(&lt.id).cloned();
-        match def {
-            Some(DefEarlyBoundRegion(_, node_id)) |
-            Some(DefLateBoundRegion(_, node_id)) |
-            Some(DefFreeRegion(_, node_id)) => {
-                if let Some(lt) = self.lt_substs.get(&node_id).cloned() {
-                    return lt;
-                }
-            }
-            _ => {}
-        }
-        hir::fold::noop_fold_lifetime(lt, self)
-    }
-}
-
 impl Clean<Type> for hir::Ty {
     fn clean(&self, cx: &DocContext) -> Type {
         use rustc::hir::*;
@@ -1696,43 +1672,47 @@ impl Clean<Type> for hir::Ty {
             },
             TyTup(ref tys) => Tuple(tys.clean(cx)),
             TyPath(None, ref path) => {
-                if let Some(tcx) = cx.tcx_opt() {
-                    // Substitute private type aliases
-                    let def = tcx.expect_def(self.id);
+                let tcx_and_def = cx.tcx_opt().map(|tcx| (tcx, tcx.expect_def(self.id)));
+                if let Some((_, def)) = tcx_and_def {
+                    if let Some(new_ty) = cx.ty_substs.borrow().get(&def).cloned() {
+                        return new_ty;
+                    }
+                }
+
+                let tcx_and_alias = tcx_and_def.and_then(|(tcx, def)| {
                     if let Def::TyAlias(def_id) = def {
-                        if let Some(node_id) = tcx.map.as_local_node_id(def_id) {
+                        // Substitute private type aliases
+                        tcx.map.as_local_node_id(def_id).and_then(|node_id| {
                             if !cx.access_levels.borrow().is_exported(def_id) {
-                                let item = tcx.map.expect_item(node_id);
-                                if let hir::ItemTy(ref ty, ref generics) = item.node {
-                                    let provided_params = &path.segments.last().unwrap().parameters;
-                                    let mut ty_substs = FnvHashMap();
-                                    let mut lt_substs = FnvHashMap();
-                                    for (i, ty_param) in generics.ty_params.iter().enumerate() {
-                                        let ty_param_def = tcx.expect_def(ty_param.id);
-                                        if let Some(ty) = provided_params.types().get(i).cloned()
-                                                                                        .cloned() {
-                                            ty_substs.insert(ty_param_def, ty.unwrap());
-                                        } else if let Some(default) = ty_param.default.clone() {
-                                            ty_substs.insert(ty_param_def, default.unwrap());
-                                        }
-                                    }
-                                    for (i, lt_param) in generics.lifetimes.iter().enumerate() {
-                                        if let Some(lt) = provided_params.lifetimes().get(i)
-                                                                                     .cloned()
-                                                                                     .cloned() {
-                                            lt_substs.insert(lt_param.lifetime.id, lt);
-                                        }
-                                    }
-                                    let mut subst_alias = SubstAlias {
-                                        tcx: &tcx,
-                                        ty_substs: ty_substs,
-                                        lt_substs: lt_substs
-                                    };
-                                    return subst_alias.fold_ty(ty.clone()).clean(cx);
-                                }
+                                Some((tcx, &tcx.map.expect_item(node_id).node))
+                            } else {
+                                None
                             }
+                        })
+                    } else {
+                        None
+                    }
+                });
+                if let Some((tcx, &hir::ItemTy(ref ty, ref generics))) = tcx_and_alias {
+                    let provided_params = &path.segments.last().unwrap().parameters;
+                    let mut ty_substs = FnvHashMap();
+                    let mut lt_substs = FnvHashMap();
+                    for (i, ty_param) in generics.ty_params.iter().enumerate() {
+                        let ty_param_def = tcx.expect_def(ty_param.id);
+                        if let Some(ty) = provided_params.types().get(i).cloned()
+                                                                        .cloned() {
+                            ty_substs.insert(ty_param_def, ty.unwrap().clean(cx));
+                        } else if let Some(default) = ty_param.default.clone() {
+                            ty_substs.insert(ty_param_def, default.unwrap().clean(cx));
+                        }
+                    }
+                    for (i, lt_param) in generics.lifetimes.iter().enumerate() {
+                        if let Some(lt) = provided_params.lifetimes().get(i).cloned()
+                                                                            .cloned() {
+                            lt_substs.insert(lt_param.lifetime.id, lt.clean(cx));
                         }
                     }
+                    return cx.enter_alias(ty_substs, lt_substs, || ty.clean(cx));
                 }
                 resolve_type(cx, path.clean(cx), self.id)
             }
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index ab6858a0931..399702003ea 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -14,6 +14,7 @@ use rustc_driver::{driver, target_features, abort_on_err};
 use rustc::dep_graph::DepGraph;
 use rustc::session::{self, config};
 use rustc::hir::def_id::{CrateNum, DefId};
+use rustc::hir::def::Def;
 use rustc::middle::privacy::AccessLevels;
 use rustc::ty::{self, TyCtxt};
 use rustc::hir::map as hir_map;
@@ -23,12 +24,13 @@ use rustc_trans::back::link;
 use rustc_resolve as resolve;
 use rustc_metadata::cstore::CStore;
 
-use syntax::codemap;
+use syntax::{ast, codemap};
 use syntax::feature_gate::UnstableFeatures;
 use errors;
 use errors::emitter::ColorConfig;
 
 use std::cell::{RefCell, Cell};
+use std::mem;
 use std::rc::Rc;
 
 use visit_ast::RustdocVisitor;
@@ -63,6 +65,14 @@ pub struct DocContext<'a, 'tcx: 'a> {
     pub renderinfo: RefCell<RenderInfo>,
     /// Later on moved through `clean::Crate` into `html::render::CACHE_KEY`
     pub external_traits: RefCell<FnvHashMap<DefId, clean::Trait>>,
+
+    // The current set of type and lifetime substitutions,
+    // for expanding type aliases at the HIR level:
+
+    /// Table type parameter definition -> substituted type
+    pub ty_substs: RefCell<FnvHashMap<Def, clean::Type>>,
+    /// Table node id of lifetime parameter definition -> substituted lifetime
+    pub lt_substs: RefCell<FnvHashMap<ast::NodeId, clean::Lifetime>>,
 }
 
 impl<'b, 'tcx> DocContext<'b, 'tcx> {
@@ -84,6 +94,22 @@ impl<'b, 'tcx> DocContext<'b, 'tcx> {
         let tcx_opt = self.tcx_opt();
         tcx_opt.expect("tcx not present")
     }
+
+    /// Call the closure with the given parameters set as
+    /// the substitutions for a type alias' RHS.
+    pub fn enter_alias<F, R>(&self,
+                             ty_substs: FnvHashMap<Def, clean::Type>,
+                             lt_substs: FnvHashMap<ast::NodeId, clean::Lifetime>,
+                             f: F) -> R
+    where F: FnOnce() -> R {
+        let (old_tys, old_lts) =
+            (mem::replace(&mut *self.ty_substs.borrow_mut(), ty_substs),
+             mem::replace(&mut *self.lt_substs.borrow_mut(), lt_substs));
+        let r = f();
+        *self.ty_substs.borrow_mut() = old_tys;
+        *self.lt_substs.borrow_mut() = old_lts;
+        r
+    }
 }
 
 pub trait DocAccessLevels {
@@ -179,12 +205,14 @@ pub fn run_core(search_paths: SearchPaths,
             map: &tcx.map,
             maybe_typed: Typed(tcx),
             input: input,
-            populated_crate_impls: RefCell::new(FnvHashSet()),
+            populated_crate_impls: Default::default(),
             deref_trait_did: Cell::new(None),
             deref_mut_trait_did: Cell::new(None),
             access_levels: RefCell::new(access_levels),
-            external_traits: RefCell::new(FnvHashMap()),
-            renderinfo: RefCell::new(Default::default()),
+            external_traits: Default::default(),
+            renderinfo: Default::default(),
+            ty_substs: Default::default(),
+            lt_substs: Default::default(),
         };
         debug!("crate: {:?}", ctxt.map.krate());
 
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index 851cf95f996..3d2caeda146 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::cell::{RefCell, Cell};
+use std::cell::Cell;
 use std::env;
 use std::ffi::OsString;
 use std::io::prelude::*;
@@ -28,7 +28,6 @@ use rustc::session::{self, config};
 use rustc::session::config::{get_unstable_features_setting, OutputType,
                              OutputTypes, Externs};
 use rustc::session::search_paths::{SearchPaths, PathKind};
-use rustc::util::nodemap::{FnvHashMap, FnvHashSet};
 use rustc_back::dynamic_lib::DynamicLibrary;
 use rustc_back::tempdir::TempDir;
 use rustc_driver::{driver, Compilation};
@@ -107,12 +106,14 @@ pub fn run(input: &str,
         map: &map,
         maybe_typed: core::NotTyped(&sess),
         input: input,
-        external_traits: RefCell::new(FnvHashMap()),
-        populated_crate_impls: RefCell::new(FnvHashSet()),
+        external_traits: Default::default(),
+        populated_crate_impls: Default::default(),
         deref_trait_did: Cell::new(None),
         deref_mut_trait_did: Cell::new(None),
         access_levels: Default::default(),
         renderinfo: Default::default(),
+        ty_substs: Default::default(),
+        lt_substs: Default::default(),
     };
 
     let mut v = RustdocVisitor::new(&ctx);