syntax: dismantle ast_util.

16 files changed, 117 insertions, 489 deletions

diff --git a/src/librustc/hir/fold.rs b/src/librustc/hir/fold.rs
index e65f2fc37de..a6ff7164885 100644
--- a/src/librustc/hir/fold.rs
+++ b/src/librustc/hir/fold.rs
@@ -908,14 +908,6 @@ 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);
-    // FIXME: we should update the impl_pretty_name, but it uses pretty printing.
-    // let ident = match node {
-    //     // The node may have changed, recompute the "pretty" impl name.
-    //     ItemImpl(_, _, _, ref maybe_trait, ref ty, _) => {
-    //         impl_pretty_name(maybe_trait, Some(&**ty))
-    //     }
-    //     _ => ident
-    // };
 
     Item {
         id: id,
diff --git a/src/librustc/hir/intravisit.rs b/src/librustc/hir/intravisit.rs
index 90fba0c8985..d34d66918ca 100644
--- a/src/librustc/hir/intravisit.rs
+++ b/src/librustc/hir/intravisit.rs
@@ -27,11 +27,13 @@
 
 use syntax::abi::Abi;
 use syntax::ast::{NodeId, CRATE_NODE_ID, Name, Attribute};
-use syntax::ast_util;
 use syntax::attr::ThinAttributesExt;
 use syntax::codemap::Span;
 use hir::*;
 
+use std::cmp;
+use std::u32;
+
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub enum FnKind<'a> {
     /// fn foo() or extern "Abi" fn foo()
@@ -837,6 +839,54 @@ pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm) {
     walk_list!(visitor, visit_attribute, &arm.attrs);
 }
 
+#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
+pub struct IdRange {
+    pub min: NodeId,
+    pub max: NodeId,
+}
+
+impl IdRange {
+    pub fn max() -> IdRange {
+        IdRange {
+            min: u32::MAX,
+            max: u32::MIN,
+        }
+    }
+
+    pub fn empty(&self) -> bool {
+        self.min >= self.max
+    }
+
+    pub fn add(&mut self, id: NodeId) {
+        self.min = cmp::min(self.min, id);
+        self.max = cmp::max(self.max, id + 1);
+    }
+}
+
+pub trait IdVisitingOperation {
+    fn visit_id(&mut self, node_id: NodeId);
+}
+
+pub struct IdRangeComputingVisitor {
+    pub result: IdRange,
+}
+
+impl IdRangeComputingVisitor {
+    pub fn new() -> IdRangeComputingVisitor {
+        IdRangeComputingVisitor { result: IdRange::max() }
+    }
+
+    pub fn result(&self) -> IdRange {
+        self.result
+    }
+}
+
+impl IdVisitingOperation for IdRangeComputingVisitor {
+    fn visit_id(&mut self, id: NodeId) {
+        self.result.add(id);
+    }
+}
+
 pub struct IdVisitor<'a, O: 'a> {
     operation: &'a mut O,
 
@@ -853,7 +903,7 @@ pub struct IdVisitor<'a, O: 'a> {
     skip_members: bool,
 }
 
-impl<'a, O: ast_util::IdVisitingOperation> IdVisitor<'a, O> {
+impl<'a, O: IdVisitingOperation> IdVisitor<'a, O> {
     pub fn new(operation: &'a mut O) -> IdVisitor<'a, O> {
         IdVisitor { operation: operation, skip_members: false }
     }
@@ -868,7 +918,7 @@ impl<'a, O: ast_util::IdVisitingOperation> IdVisitor<'a, O> {
     }
 }
 
-impl<'a, 'v, O: ast_util::IdVisitingOperation> Visitor<'v> for IdVisitor<'a, O> {
+impl<'a, 'v, O: IdVisitingOperation> Visitor<'v> for IdVisitor<'a, O> {
     fn visit_mod(&mut self, module: &Mod, _: Span, node_id: NodeId) {
         self.operation.visit_id(node_id);
         walk_mod(self, module)
@@ -1012,8 +1062,8 @@ pub fn compute_id_range_for_fn_body(fk: FnKind,
                                     body: &Block,
                                     sp: Span,
                                     id: NodeId)
-                                    -> ast_util::IdRange {
-    let mut visitor = ast_util::IdRangeComputingVisitor { result: ast_util::IdRange::max() };
+                                    -> IdRange {
+    let mut visitor = IdRangeComputingVisitor { result: IdRange::max() };
     let mut id_visitor = IdVisitor::new(&mut visitor);
     id_visitor.visit_fn(fk, decl, body, sp, id);
     id_visitor.operation.result
diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs
index 18c82201924..fd45f58327f 100644
--- a/src/librustc/lint/context.rs
+++ b/src/librustc/lint/context.rs
@@ -39,7 +39,6 @@ use std::cell::RefCell;
 use std::cmp;
 use std::default::Default as StdDefault;
 use std::mem;
-use syntax::ast_util::{self, IdVisitingOperation};
 use syntax::attr::{self, AttrMetaMethods};
 use syntax::codemap::Span;
 use syntax::errors::DiagnosticBuilder;
@@ -48,7 +47,7 @@ use syntax::ast;
 use syntax::attr::ThinAttributesExt;
 use hir;
 use hir::intravisit as hir_visit;
-use hir::intravisit::IdVisitor;
+use hir::intravisit::{IdVisitor, IdVisitingOperation};
 use syntax::visit as ast_visit;
 
 /// Information about the registered lints.
@@ -654,16 +653,6 @@ impl<'a> EarlyContext<'a> {
             level_stack: vec![],
         }
     }
-
-    fn visit_ids<F>(&mut self, f: F)
-        where F: FnOnce(&mut ast_util::IdVisitor<EarlyContext>)
-    {
-        let mut v = ast_util::IdVisitor {
-            operation: self,
-            visited_outermost: false,
-        };
-        f(&mut v);
-    }
 }
 
 impl<'a, 'tcx> LateContext<'a, 'tcx> {
@@ -928,7 +917,6 @@ impl<'a, 'v> ast_visit::Visitor<'v> for EarlyContext<'a> {
     fn visit_item(&mut self, it: &ast::Item) {
         self.with_lint_attrs(&it.attrs, |cx| {
             run_lints!(cx, check_item, early_passes, it);
-            cx.visit_ids(|v| v.visit_item(it));
             ast_visit::walk_item(cx, it);
             run_lints!(cx, check_item_post, early_passes, it);
         })
@@ -1042,7 +1030,6 @@ impl<'a, 'v> ast_visit::Visitor<'v> for EarlyContext<'a> {
     fn visit_trait_item(&mut self, trait_item: &ast::TraitItem) {
         self.with_lint_attrs(&trait_item.attrs, |cx| {
             run_lints!(cx, check_trait_item, early_passes, trait_item);
-            cx.visit_ids(|v| v.visit_trait_item(trait_item));
             ast_visit::walk_trait_item(cx, trait_item);
             run_lints!(cx, check_trait_item_post, early_passes, trait_item);
         });
@@ -1051,7 +1038,6 @@ impl<'a, 'v> ast_visit::Visitor<'v> for EarlyContext<'a> {
     fn visit_impl_item(&mut self, impl_item: &ast::ImplItem) {
         self.with_lint_attrs(&impl_item.attrs, |cx| {
             run_lints!(cx, check_impl_item, early_passes, impl_item);
-            cx.visit_ids(|v| v.visit_impl_item(impl_item));
             ast_visit::walk_impl_item(cx, impl_item);
             run_lints!(cx, check_impl_item_post, early_passes, impl_item);
         });
@@ -1099,18 +1085,6 @@ impl<'a, 'tcx> IdVisitingOperation for LateContext<'a, 'tcx> {
         }
     }
 }
-impl<'a> IdVisitingOperation for EarlyContext<'a> {
-    fn visit_id(&mut self, id: ast::NodeId) {
-        match self.sess.lints.borrow_mut().remove(&id) {
-            None => {}
-            Some(lints) => {
-                for (lint_id, span, msg) in lints {
-                    self.span_lint(lint_id.lint, span, &msg[..])
-                }
-            }
-        }
-    }
-}
 
 // This lint pass is defined here because it touches parts of the `LateContext`
 // that we don't want to expose. It records the lint level at certain AST
@@ -1292,11 +1266,12 @@ pub fn check_ast_crate(sess: &Session, krate: &ast::Crate) {
 
     // Visit the whole crate.
     cx.with_lint_attrs(&krate.attrs, |cx| {
-        cx.visit_id(ast::CRATE_NODE_ID);
-        cx.visit_ids(|v| {
-            v.visited_outermost = true;
-            ast_visit::walk_crate(v, krate);
-        });
+        // Lints may be assigned to the whole crate.
+        if let Some(lints) = cx.sess.lints.borrow_mut().remove(&ast::CRATE_NODE_ID) {
+            for (lint_id, span, msg) in lints {
+                cx.span_lint(lint_id.lint, span, &msg[..])
+            }
+        }
 
         // since the root module isn't visited as an item (because it isn't an
         // item), warn for it here.
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 3ac2c384134..a7f415ef2a0 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -38,14 +38,13 @@ use std::cell::RefCell;
 use std::rc::Rc;
 use std::path::PathBuf;
 use syntax::ast;
-use syntax::ast_util::{IdVisitingOperation};
 use syntax::attr;
 use syntax::codemap::Span;
 use syntax::ptr::P;
 use syntax::parse::token::InternedString;
 use rustc_back::target::Target;
 use hir;
-use hir::intravisit::{IdVisitor, Visitor};
+use hir::intravisit::{IdVisitor, IdVisitingOperation, Visitor};
 
 pub use self::DefLike::{DlDef, DlField, DlImpl};
 pub use self::NativeLibraryKind::{NativeStatic, NativeFramework, NativeUnknown};
diff --git a/src/librustc/middle/dataflow.rs b/src/librustc/middle/dataflow.rs
index 99b512141a4..1aaaa4bcd77 100644
--- a/src/librustc/middle/dataflow.rs
+++ b/src/librustc/middle/dataflow.rs
@@ -21,12 +21,11 @@ use std::io;
 use std::mem;
 use std::usize;
 use syntax::ast;
-use syntax::ast_util::IdRange;
 use syntax::print::pp;
 use syntax::print::pprust::PrintState;
 use util::nodemap::NodeMap;
 use hir;
-use hir::intravisit;
+use hir::intravisit::{self, IdRange};
 use hir::print as pprust;
 
 
diff --git a/src/librustc_borrowck/borrowck/move_data.rs b/src/librustc_borrowck/borrowck/move_data.rs
index 292cfcfeac1..80e408e9a6e 100644
--- a/src/librustc_borrowck/borrowck/move_data.rs
+++ b/src/librustc_borrowck/borrowck/move_data.rs
@@ -28,9 +28,9 @@ use std::cell::RefCell;
 use std::rc::Rc;
 use std::usize;
 use syntax::ast;
-use syntax::ast_util;
 use syntax::codemap::Span;
 use rustc::hir;
+use rustc::hir::intravisit::IdRange;
 
 #[path="fragments.rs"]
 pub mod fragments;
@@ -602,7 +602,7 @@ impl<'a, 'tcx> FlowedMoveData<'a, 'tcx> {
     pub fn new(move_data: MoveData<'tcx>,
                tcx: &'a TyCtxt<'tcx>,
                cfg: &cfg::CFG,
-               id_range: ast_util::IdRange,
+               id_range: IdRange,
                decl: &hir::FnDecl,
                body: &hir::Block)
                -> FlowedMoveData<'a, 'tcx> {
diff --git a/src/librustc_const_eval/check_match.rs b/src/librustc_const_eval/check_match.rs
index d290652576d..797580319b2 100644
--- a/src/librustc_const_eval/check_match.rs
+++ b/src/librustc_const_eval/check_match.rs
@@ -34,11 +34,10 @@ use std::iter::{FromIterator, IntoIterator, repeat};
 
 use rustc::hir;
 use rustc::hir::{Pat, PatKind};
-use rustc::hir::intravisit::{self, IdVisitor, Visitor, FnKind};
+use rustc::hir::intravisit::{self, IdVisitor, IdVisitingOperation, Visitor, FnKind};
 use rustc_back::slice;
 
 use syntax::ast::{self, DUMMY_NODE_ID, NodeId};
-use syntax::ast_util;
 use syntax::codemap::{Span, Spanned, DUMMY_SP};
 use rustc::hir::fold::{Folder, noop_fold_pat};
 use rustc::hir::print::pat_to_string;
@@ -460,7 +459,7 @@ struct RenamingRecorder<'map> {
     renaming_map: &'map mut FnvHashMap<(NodeId, Span), NodeId>
 }
 
-impl<'map> ast_util::IdVisitingOperation for RenamingRecorder<'map> {
+impl<'map> IdVisitingOperation 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);
diff --git a/src/librustc_metadata/astencode.rs b/src/librustc_metadata/astencode.rs
index 98e73f2902b..61f35a12df7 100644
--- a/src/librustc_metadata/astencode.rs
+++ b/src/librustc_metadata/astencode.rs
@@ -18,6 +18,7 @@ use rustc::session::Session;
 use rustc::hir;
 use rustc::hir::fold;
 use rustc::hir::fold::Folder;
+use rustc::hir::intravisit::{IdRange, IdRangeComputingVisitor, IdVisitingOperation};
 
 use common as c;
 use cstore;
@@ -36,7 +37,7 @@ use middle::region;
 use rustc::ty::subst;
 use rustc::ty::{self, Ty, TyCtxt};
 
-use syntax::{ast, ast_util, codemap};
+use syntax::{ast, codemap};
 use syntax::ast::NodeIdAssigner;
 use syntax::ptr::P;
 
@@ -61,8 +62,8 @@ use serialize::EncoderHelpers;
 struct DecodeContext<'a, 'b, 'tcx: 'a> {
     tcx: &'a TyCtxt<'tcx>,
     cdata: &'b cstore::crate_metadata,
-    from_id_range: ast_util::IdRange,
-    to_id_range: ast_util::IdRange,
+    from_id_range: IdRange,
+    to_id_range: IdRange,
     // Cache the last used filemap for translating spans as an optimization.
     last_filemap_index: Cell<usize>,
 }
@@ -178,13 +179,13 @@ pub fn decode_inlined_item<'tcx>(cdata: &cstore::crate_metadata,
 // Enumerating the IDs which appear in an AST
 
 fn reserve_id_range(sess: &Session,
-                    from_id_range: ast_util::IdRange) -> ast_util::IdRange {
+                    from_id_range: IdRange) -> IdRange {
     // Handle the case of an empty range:
     if from_id_range.empty() { return from_id_range; }
     let cnt = from_id_range.max - from_id_range.min;
     let to_id_min = sess.reserve_node_ids(cnt);
     let to_id_max = to_id_min + cnt;
-    ast_util::IdRange { min: to_id_min, max: to_id_max }
+    IdRange { min: to_id_min, max: to_id_max }
 }
 
 impl<'a, 'b, 'tcx> DecodeContext<'a, 'b, 'tcx> {
@@ -705,7 +706,7 @@ struct SideTableEncodingIdVisitor<'a, 'b:'a, 'c:'a, 'tcx:'c> {
     rbml_w: &'a mut Encoder<'b>,
 }
 
-impl<'a, 'b, 'c, 'tcx> ast_util::IdVisitingOperation for
+impl<'a, 'b, 'c, 'tcx> IdVisitingOperation for
         SideTableEncodingIdVisitor<'a, 'b, 'c, 'tcx> {
     fn visit_id(&mut self, id: ast::NodeId) {
         encode_side_tables_for_id(self.ecx, self.rbml_w, id)
@@ -1261,8 +1262,8 @@ fn copy_item_types(dcx: &DecodeContext, ii: &InlinedItem, orig_did: DefId) {
     }
 }
 
-fn inlined_item_id_range(v: &InlinedItem) -> ast_util::IdRange {
-    let mut visitor = ast_util::IdRangeComputingVisitor::new();
+fn inlined_item_id_range(v: &InlinedItem) -> IdRange {
+    let mut visitor = IdRangeComputingVisitor::new();
     v.visit_ids(&mut visitor);
     visitor.result()
 }
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index e65bf5be256..a4f9720bbe2 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -39,7 +39,6 @@ use std::fs::{self, File};
 use std::path::{Path, PathBuf};
 
 use syntax::ast::{self, NodeId, PatKind};
-use syntax::ast_util;
 use syntax::codemap::*;
 use syntax::parse::token::{self, keywords};
 use syntax::visit::{self, Visitor};
@@ -670,7 +669,7 @@ impl<'v> Visitor<'v> for PathCollector {
                     ast::BindingMode::ByValue(mt) => mt,
                 };
                 // collect path for either visit_local or visit_arm
-                let path = ast_util::ident_to_path(path1.span, path1.node);
+                let path = ast::Path::from_ident(path1.span, path1.node);
                 self.collected_paths.push((p.id, path, immut, recorder::VarRef));
             }
             _ => {}
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index a441f2990cd..370dd0dad72 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -205,6 +205,23 @@ impl fmt::Display for Path {
     }
 }
 
+impl Path {
+    // convert a span and an identifier to the corresponding
+    // 1-segment path
+    pub fn from_ident(s: Span, identifier: Ident) -> Path {
+        Path {
+            span: s,
+            global: false,
+            segments: vec!(
+                PathSegment {
+                    identifier: identifier,
+                    parameters: PathParameters::none()
+                }
+            ),
+        }
+    }
+}
+
 /// A segment of a path: an identifier, an optional lifetime, and a set of
 /// types.
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs
deleted file mode 100644
index 852b153044f..00000000000
--- a/src/libsyntax/ast_util.rs
+++ /dev/null
@@ -1,398 +0,0 @@
-// Copyright 2012-2014 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.
-
-use ast::*;
-use ast;
-use codemap;
-use codemap::Span;
-use parse::token;
-use print::pprust;
-use ptr::P;
-use visit::{FnKind, Visitor};
-use visit;
-
-use std::cmp;
-use std::u32;
-
-pub fn path_name_i(idents: &[Ident]) -> String {
-    // FIXME: Bad copies (#2543 -- same for everything else that says "bad")
-    idents.iter().map(|i| i.to_string()).collect::<Vec<String>>().join("::")
-}
-
-pub fn is_path(e: P<Expr>) -> bool {
-    match e.node { ExprKind::Path(..) => true, _ => false }
-}
-
-
-// convert a span and an identifier to the corresponding
-// 1-segment path
-pub fn ident_to_path(s: Span, identifier: Ident) -> Path {
-    ast::Path {
-        span: s,
-        global: false,
-        segments: vec!(
-            ast::PathSegment {
-                identifier: identifier,
-                parameters: ast::PathParameters::AngleBracketed(ast::AngleBracketedParameterData {
-                    lifetimes: Vec::new(),
-                    types: P::empty(),
-                    bindings: P::empty(),
-                })
-            }
-        ),
-    }
-}
-
-// If path is a single segment ident path, return that ident. Otherwise, return
-// None.
-pub fn path_to_ident(path: &Path) -> Option<Ident> {
-    if path.segments.len() != 1 {
-        return None;
-    }
-
-    let segment = &path.segments[0];
-    if !segment.parameters.is_empty() {
-        return None;
-    }
-
-    Some(segment.identifier)
-}
-
-pub fn ident_to_pat(id: NodeId, s: Span, i: Ident) -> P<Pat> {
-    let spanned = codemap::Spanned{ span: s, node: i };
-    P(Pat {
-        id: id,
-        node: PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), spanned, None),
-        span: s
-    })
-}
-
-/// Generate a "pretty" name for an `impl` from its type and trait.
-/// This is designed so that symbols of `impl`'d methods give some
-/// hint of where they came from, (previously they would all just be
-/// listed as `__extensions__::method_name::hash`, with no indication
-/// of the type).
-pub fn impl_pretty_name(trait_ref: &Option<TraitRef>, ty: Option<&Ty>) -> Ident {
-    let mut pretty = match ty {
-        Some(t) => pprust::ty_to_string(t),
-        None => String::from("..")
-    };
-
-    match *trait_ref {
-        Some(ref trait_ref) => {
-            pretty.push('.');
-            pretty.push_str(&pprust::path_to_string(&trait_ref.path));
-        }
-        None => {}
-    }
-    token::gensym_ident(&pretty[..])
-}
-
-pub fn struct_field_visibility(field: ast::StructField) -> Visibility {
-    match field.node.kind {
-        ast::NamedField(_, v) | ast::UnnamedField(v) => v
-    }
-}
-
-// ______________________________________________________________________
-// Enumerating the IDs which appear in an AST
-
-#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct IdRange {
-    pub min: NodeId,
-    pub max: NodeId,
-}
-
-impl IdRange {
-    pub fn max() -> IdRange {
-        IdRange {
-            min: u32::MAX,
-            max: u32::MIN,
-        }
-    }
-
-    pub fn empty(&self) -> bool {
-        self.min >= self.max
-    }
-
-    pub fn add(&mut self, id: NodeId) {
-        self.min = cmp::min(self.min, id);
-        self.max = cmp::max(self.max, id + 1);
-    }
-}
-
-pub trait IdVisitingOperation {
-    fn visit_id(&mut self, node_id: NodeId);
-}
-
-/// A visitor that applies its operation to all of the node IDs
-/// in a visitable thing.
-
-pub struct IdVisitor<'a, O:'a> {
-    pub operation: &'a mut O,
-    pub visited_outermost: bool,
-}
-
-impl<'a, O: IdVisitingOperation> IdVisitor<'a, O> {
-    fn visit_generics_helper(&mut self, generics: &Generics) {
-        for type_parameter in generics.ty_params.iter() {
-            self.operation.visit_id(type_parameter.id)
-        }
-        for lifetime in &generics.lifetimes {
-            self.operation.visit_id(lifetime.lifetime.id)
-        }
-    }
-}
-
-impl<'a, 'v, O: IdVisitingOperation> Visitor<'v> for IdVisitor<'a, O> {
-    fn visit_mod(&mut self,
-                 module: &Mod,
-                 _: Span,
-                 node_id: NodeId) {
-        self.operation.visit_id(node_id);
-        visit::walk_mod(self, module)
-    }
-
-    fn visit_foreign_item(&mut self, foreign_item: &ForeignItem) {
-        self.operation.visit_id(foreign_item.id);
-        visit::walk_foreign_item(self, foreign_item)
-    }
-
-    fn visit_item(&mut self, item: &Item) {
-        if self.visited_outermost {
-            return
-        } else {
-            self.visited_outermost = true
-        }
-
-        self.operation.visit_id(item.id);
-        match item.node {
-            ItemKind::Use(ref view_path) => {
-                match view_path.node {
-                    ViewPathSimple(_, _) |
-                    ViewPathGlob(_) => {}
-                    ViewPathList(_, ref paths) => {
-                        for path in paths {
-                            self.operation.visit_id(path.node.id())
-                        }
-                    }
-                }
-            }
-            _ => {}
-        }
-
-        visit::walk_item(self, item);
-
-        self.visited_outermost = false
-    }
-
-    fn visit_local(&mut self, local: &Local) {
-        self.operation.visit_id(local.id);
-        visit::walk_local(self, local)
-    }
-
-    fn visit_block(&mut self, block: &Block) {
-        self.operation.visit_id(block.id);
-        visit::walk_block(self, block)
-    }
-
-    fn visit_stmt(&mut self, statement: &Stmt) {
-        self.operation
-            .visit_id(statement.node.id().expect("attempted to visit unexpanded stmt"));
-        visit::walk_stmt(self, statement)
-    }
-
-    fn visit_pat(&mut self, pattern: &Pat) {
-        self.operation.visit_id(pattern.id);
-        visit::walk_pat(self, pattern)
-    }
-
-    fn visit_expr(&mut self, expression: &Expr) {
-        self.operation.visit_id(expression.id);
-        visit::walk_expr(self, expression)
-    }
-
-    fn visit_ty(&mut self, typ: &Ty) {
-        self.operation.visit_id(typ.id);
-        visit::walk_ty(self, typ)
-    }
-
-    fn visit_generics(&mut self, generics: &Generics) {
-        self.visit_generics_helper(generics);
-        visit::walk_generics(self, generics)
-    }
-
-    fn visit_fn(&mut self,
-                function_kind: visit::FnKind<'v>,
-                function_declaration: &'v FnDecl,
-                block: &'v Block,
-                span: Span,
-                node_id: NodeId) {
-        match function_kind {
-            FnKind::Method(..) if self.visited_outermost => return,
-            FnKind::Method(..) => self.visited_outermost = true,
-            _ => {}
-        }
-
-        self.operation.visit_id(node_id);
-
-        match function_kind {
-            FnKind::ItemFn(_, generics, _, _, _, _) => {
-                self.visit_generics_helper(generics)
-            }
-            FnKind::Method(_, ref sig, _) => {
-                self.visit_generics_helper(&sig.generics)
-            }
-            FnKind::Closure => {}
-        }
-
-        for argument in &function_declaration.inputs {
-            self.operation.visit_id(argument.id)
-        }
-
-        visit::walk_fn(self,
-                       function_kind,
-                       function_declaration,
-                       block,
-                       span);
-
-        if let FnKind::Method(..) = function_kind {
-            self.visited_outermost = false;
-        }
-    }
-
-    fn visit_struct_field(&mut self, struct_field: &StructField) {
-        self.operation.visit_id(struct_field.node.id);
-        visit::walk_struct_field(self, struct_field)
-    }
-
-    fn visit_variant_data(&mut self,
-                        struct_def: &VariantData,
-                        _: ast::Ident,
-                        _: &ast::Generics,
-                        _: NodeId,
-                        _: Span) {
-        self.operation.visit_id(struct_def.id());
-        visit::walk_struct_def(self, struct_def);
-    }
-
-    fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
-        self.operation.visit_id(ti.id);
-        visit::walk_trait_item(self, ti);
-    }
-
-    fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
-        self.operation.visit_id(ii.id);
-        visit::walk_impl_item(self, ii);
-    }
-
-    fn visit_lifetime(&mut self, lifetime: &Lifetime) {
-        self.operation.visit_id(lifetime.id);
-    }
-
-    fn visit_lifetime_def(&mut self, def: &LifetimeDef) {
-        self.visit_lifetime(&def.lifetime);
-    }
-
-    fn visit_trait_ref(&mut self, trait_ref: &TraitRef) {
-        self.operation.visit_id(trait_ref.ref_id);
-        visit::walk_trait_ref(self, trait_ref);
-    }
-}
-
-pub struct IdRangeComputingVisitor {
-    pub result: IdRange,
-}
-
-impl IdRangeComputingVisitor {
-    pub fn new() -> IdRangeComputingVisitor {
-        IdRangeComputingVisitor { result: IdRange::max() }
-    }
-
-    pub fn result(&self) -> IdRange {
-        self.result
-    }
-}
-
-impl IdVisitingOperation for IdRangeComputingVisitor {
-    fn visit_id(&mut self, id: NodeId) {
-        self.result.add(id);
-    }
-}
-
-/// Computes the id range for a single fn body, ignoring nested items.
-pub fn compute_id_range_for_fn_body(fk: FnKind,
-                                    decl: &FnDecl,
-                                    body: &Block,
-                                    sp: Span,
-                                    id: NodeId)
-                                    -> IdRange
-{
-    let mut visitor = IdRangeComputingVisitor::new();
-    let mut id_visitor = IdVisitor {
-        operation: &mut visitor,
-        visited_outermost: false,
-    };
-    id_visitor.visit_fn(fk, decl, body, sp, id);
-    id_visitor.operation.result
-}
-
-/// Returns true if the given pattern consists solely of an identifier
-/// and false otherwise.
-pub fn pat_is_ident(pat: P<ast::Pat>) -> bool {
-    match pat.node {
-        PatKind::Ident(..) => true,
-        _ => false,
-    }
-}
-
-// are two paths equal when compared unhygienically?
-// since I'm using this to replace ==, it seems appropriate
-// to compare the span, global, etc. fields as well.
-pub fn path_name_eq(a : &ast::Path, b : &ast::Path) -> bool {
-    (a.span.source_equal(&b.span))
-    && (a.global == b.global)
-    && (segments_name_eq(&a.segments[..], &b.segments[..]))
-}
-
-// are two arrays of segments equal when compared unhygienically?
-pub fn segments_name_eq(a : &[ast::PathSegment], b : &[ast::PathSegment]) -> bool {
-    a.len() == b.len() &&
-    a.iter().zip(b).all(|(s, t)| {
-        s.identifier.name == t.identifier.name &&
-        // FIXME #7743: ident -> name problems in lifetime comparison?
-        // can types contain idents?
-        s.parameters == t.parameters
-    })
-}
-
-#[cfg(test)]
-mod tests {
-    use ast::*;
-    use super::*;
-
-    fn ident_to_segment(id: Ident) -> PathSegment {
-        PathSegment {identifier: id,
-                     parameters: PathParameters::none()}
-    }
-
-    #[test] fn idents_name_eq_test() {
-        assert!(segments_name_eq(
-            &[Ident::new(Name(3),SyntaxContext(4)), Ident::new(Name(78),SyntaxContext(82))]
-                .iter().cloned().map(ident_to_segment).collect::<Vec<PathSegment>>(),
-            &[Ident::new(Name(3),SyntaxContext(104)), Ident::new(Name(78),SyntaxContext(182))]
-                .iter().cloned().map(ident_to_segment).collect::<Vec<PathSegment>>()));
-        assert!(!segments_name_eq(
-            &[Ident::new(Name(3),SyntaxContext(4)), Ident::new(Name(78),SyntaxContext(82))]
-                .iter().cloned().map(ident_to_segment).collect::<Vec<PathSegment>>(),
-            &[Ident::new(Name(3),SyntaxContext(104)), Ident::new(Name(77),SyntaxContext(182))]
-                .iter().cloned().map(ident_to_segment).collect::<Vec<PathSegment>>()));
-    }
-}
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 46bcb8067a3..55eec165517 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -21,7 +21,6 @@
 use ast::*;
 use ast;
 use attr::{ThinAttributes, ThinAttributesExt};
-use ast_util;
 use codemap::{respan, Span, Spanned};
 use parse::token;
 use ptr::P;
@@ -1073,13 +1072,6 @@ pub fn noop_fold_item_simple<T: Folder>(Item {id, ident, attrs, node, vis, span}
                                         folder: &mut T) -> Item {
     let id = folder.new_id(id);
     let node = folder.fold_item_kind(node);
-    let ident = match node {
-        // The node may have changed, recompute the "pretty" impl name.
-        ItemKind::Impl(_, _, _, ref maybe_trait, ref ty, _) => {
-            ast_util::impl_pretty_name(maybe_trait, Some(&ty))
-        }
-        _ => ident
-    };
 
     Item {
         id: id,
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 7f8472f8b28..ab14e21e251 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -91,7 +91,6 @@ pub mod syntax {
 
 pub mod abi;
 pub mod ast;
-pub mod ast_util;
 pub mod attr;
 pub mod codemap;
 pub mod config;
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 89a504e1ebd..36f01463205 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -44,7 +44,6 @@ use ast::{Visibility, WhereClause};
 use attr::{ThinAttributes, ThinAttributesExt, AttributesExt};
 use ast::{BinOpKind, UnOp};
 use ast;
-use ast_util::{self, ident_to_path};
 use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp, CodeMap};
 use errors::{self, DiagnosticBuilder};
 use ext::tt::macro_parser;
@@ -1577,9 +1576,14 @@ impl<'a> Parser<'a> {
             pat
         } else {
             debug!("parse_arg_general ident_to_pat");
-            ast_util::ident_to_pat(ast::DUMMY_NODE_ID,
-                                   self.last_span,
-                                   special_idents::invalid)
+            let sp = self.last_span;
+            let spanned = Spanned { span: sp, node: special_idents::invalid };
+            P(Pat {
+                id: ast::DUMMY_NODE_ID,
+                node: PatKind::Ident(BindingMode::ByValue(Mutability::Immutable),
+                                     spanned, None),
+                span: sp
+            })
         };
 
         let t = self.parse_ty_sum()?;
@@ -2223,7 +2227,7 @@ impl<'a> Parser<'a> {
                             ctxt: _
                          }, token::Plain) => {
                 self.bump();
-                let path = ast_util::ident_to_path(mk_sp(lo, hi), id);
+                let path = ast::Path::from_ident(mk_sp(lo, hi), id);
                 ex = ExprKind::Path(None, path);
                 hi = self.last_span.hi;
             }
@@ -3679,7 +3683,7 @@ impl<'a> Parser<'a> {
                         // Parse macro invocation
                         let ident = self.parse_ident()?;
                         let ident_span = self.last_span;
-                        let path = ident_to_path(ident_span, ident);
+                        let path = ast::Path::from_ident(ident_span, ident);
                         self.bump();
                         let delim = self.expect_open_delim()?;
                         let tts = self.parse_seq_to_end(
@@ -5116,7 +5120,7 @@ impl<'a> Parser<'a> {
 
             self.expect(&token::OpenDelim(token::Brace))?;
             self.expect(&token::CloseDelim(token::Brace))?;
-            Ok((ast_util::impl_pretty_name(&opt_trait, None),
+            Ok((special_idents::invalid,
              ItemKind::DefaultImpl(unsafety, opt_trait.unwrap()), None))
         } else {
             if opt_trait.is_some() {
@@ -5132,7 +5136,7 @@ impl<'a> Parser<'a> {
                 impl_items.push(self.parse_impl_item()?);
             }
 
-            Ok((ast_util::impl_pretty_name(&opt_trait, Some(&ty)),
+            Ok((special_idents::invalid,
              ItemKind::Impl(unsafety, polarity, generics, opt_trait, ty, impl_items),
              Some(attrs)))
         }
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index 81b702e794d..703b1611540 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -18,7 +18,6 @@ use std::iter;
 use std::slice;
 use std::mem;
 use std::vec;
-use ast_util::*;
 use attr::AttrMetaMethods;
 use attr;
 use codemap::{DUMMY_SP, Span, ExpnInfo, NameAndSpan, MacroAttribute};
@@ -35,7 +34,7 @@ use fold;
 use parse::token::{intern, InternedString};
 use parse::{token, ParseSess};
 use print::pprust;
-use {ast, ast_util};
+use ast;
 use ptr::P;
 use util::small_vector::SmallVector;
 
@@ -120,8 +119,7 @@ impl<'a> fold::Folder for TestHarnessGenerator<'a> {
         if ident.name != token::special_idents::invalid.name {
             self.cx.path.push(ident);
         }
-        debug!("current path: {}",
-               ast_util::path_name_i(&self.cx.path));
+        debug!("current path: {}", path_name_i(&self.cx.path));
 
         let i = if is_test_fn(&self.cx, &i) || is_bench_fn(&self.cx, &i) {
             match i.node {
@@ -349,7 +347,6 @@ enum HasTestSignature {
     NotEvenAFunction,
 }
 
-
 fn is_test_fn(cx: &TestCtxt, i: &ast::Item) -> bool {
     let has_test_attr = attr::contains_name(&i.attrs, "test");
 
@@ -576,6 +573,11 @@ fn path_node(ids: Vec<ast::Ident> ) -> ast::Path {
     }
 }
 
+fn path_name_i(idents: &[ast::Ident]) -> String {
+    // FIXME: Bad copies (#2543 -- same for everything else that says "bad")
+    idents.iter().map(|i| i.to_string()).collect::<Vec<String>>().join("::")
+}
+
 fn mk_tests(cx: &TestCtxt) -> P<ast::Item> {
     // The vector of test_descs for this crate
     let test_descs = mk_test_descs(cx);
@@ -645,10 +647,10 @@ fn mk_test_desc_and_fn_rec(cx: &TestCtxt, test: &Test) -> P<ast::Expr> {
     // creates $name: $expr
     let field = |name, expr| ecx.field_imm(span, ecx.ident_of(name), expr);
 
-    debug!("encoding {}", ast_util::path_name_i(&path[..]));
+    debug!("encoding {}", path_name_i(&path[..]));
 
     // path to the #[test] function: "foo::bar::baz"
-    let path_string = ast_util::path_name_i(&path[..]);
+    let path_string = path_name_i(&path[..]);
     let name_expr = ecx.expr_str(span, token::intern_and_get_ident(&path_string[..]));
 
     // self::test::StaticTestName($name_expr)
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index 7d452b14dae..37c77ec5b2f 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -194,7 +194,6 @@ use std::vec;
 
 use syntax::abi::Abi;
 use syntax::ast::{self, EnumDef, Expr, Ident, Generics, VariantData, BinOpKind, PatKind};
-use syntax::ast_util;
 use syntax::attr;
 use syntax::attr::AttrMetaMethods;
 use syntax::ext::base::{ExtCtxt, Annotatable};
@@ -620,7 +619,6 @@ impl<'a> TraitDef<'a> {
         // Just mark it now since we know that it'll end up used downstream
         attr::mark_used(&attr);
         let opt_trait_ref = Some(trait_ref);
-        let ident = ast_util::impl_pretty_name(&opt_trait_ref, Some(&self_type));
         let unused_qual = cx.attribute(
             self.span,
             cx.meta_list(self.span,
@@ -638,7 +636,7 @@ impl<'a> TraitDef<'a> {
 
         cx.item(
             self.span,
-            ident,
+            special_idents::invalid,
             a,
             ast::ItemKind::Impl(unsafety,
                                 ast::ImplPolarity::Positive,