Remove the deprecated box(PLACE) syntax.

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }

src/liballoc/boxed.rs

@@ -80,11 +80,10 @@ use core::raw::{TraitObject};
 /// use std::boxed::HEAP;
 ///
 /// fn main() {
-/// let foo = box(HEAP) 5;
+/// let foo: Box<i32> = in HEAP { 5 };
 /// let foo = box 5;
 /// }
 /// ```
-#[lang = "exchange_heap"]
 #[unstable(feature = "box_heap",
  reason = "may be renamed; uncertain about custom allocator design",
  issue = "27779")]

src/librustc/middle/cfg/construct.rs

@@ -344,13 +344,12 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
  self.straightline(expr, pred, [r, l].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(Some(ref l), ref r) |
  hir::ExprIndex(ref l, ref r) |
  hir::ExprBinary(_, ref l, ref r) => { // NB: && and || handled earlier
  self.straightline(expr, pred, [l, r].iter().map(|&e| &**e))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) |

src/librustc/middle/check_const.rs

@@ -568,8 +568,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
  "user-defined operators are not allowed in {}s", v.msg());
  }
  }
- hir::ExprBox(..) |
- hir::ExprUnary(hir::UnUniq, _) => {
+ hir::ExprBox(_) => {
  v.add_qualif(ConstQualif::NOT_CONST);
  if v.mode != Mode::Var {
  span_err!(v.tcx.sess, e.span, E0010,

src/librustc/middle/expr_use_visitor.rs

@@ -280,13 +280,11 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  typer: &'t infer::InferCtxt<'a, 'tcx>)
  -> ExprUseVisitor<'d,'t,'a,'tcx>
  {
-let result = ExprUseVisitor {
+ ExprUseVisitor {
  typer: typer,
  mc: mc::MemCategorizationContext::new(typer),
  delegate: delegate,
- };
-
- result
+ }
  }
 
  pub fn walk_fn(&mut self,
@@ -544,17 +542,8 @@ impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
  self.walk_captures(expr)
  }
 
- hir::ExprBox(ref place, ref base) => {
- match *place {
- Some(ref place) => self.consume_expr(&**place),
- None => {}
- }
+ hir::ExprBox(ref base) => {
  self.consume_expr(&**base);
- if place.is_some() {
- self.tcx().sess.span_bug(
- expr.span,
- "box with explicit place remains after expansion");
- }
  }
  }
  }

src/librustc/middle/lang_items.rs

@@ -341,7 +341,6 @@ lets_do_this! {
  EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
  MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
 
- ExchangeHeapLangItem, "exchange_heap", exchange_heap;
  OwnedBoxLangItem, "owned_box", owned_box;
 
  PhantomDataItem, "phantom_data", phantom_data;

src/librustc/middle/liveness.rs

@@ -1147,8 +1147,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  }
 
  hir::ExprIndex(ref l, ref r) |
- hir::ExprBinary(_, ref l, ref r) |
- hir::ExprBox(Some(ref l), ref r) => {
+ hir::ExprBinary(_, ref l, ref r) => {
  let r_succ = self.propagate_through_expr(&**r, succ);
  self.propagate_through_expr(&**l, r_succ)
  }
@@ -1158,7 +1157,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
  }
 
- hir::ExprBox(None, ref e) |
+ hir::ExprBox(ref e) |
  hir::ExprAddrOf(_, ref e) |
  hir::ExprCast(ref e, _) |
  hir::ExprUnary(_, ref e) => {

src/librustc/middle/region.rs

@@ -994,9 +994,6 @@ fn resolve_local(visitor: &mut RegionResolutionVisitor, local: &hir::Local) {
  visitor, &**subexpr, blk_id);
  }
  }
- hir::ExprUnary(hir::UnUniq, ref subexpr) => {
- record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id);
- }
  hir::ExprCast(ref subexpr, _) => {
  record_rvalue_scope_if_borrow_expr(visitor, &**subexpr, blk_id)
  }

src/librustc_front/fold.rs

@@ -1040,8 +1040,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
  Expr {
  id: folder.new_id(id),
  node: match node {
- ExprBox(p, e) => {
- ExprBox(p.map(|e|folder.fold_expr(e)), folder.fold_expr(e))
+ ExprBox(e) => {
+ ExprBox(folder.fold_expr(e))
  }
  ExprVec(exprs) => {
  ExprVec(exprs.move_map(|x| folder.fold_expr(x)))

src/librustc_front/hir.rs

@@ -491,8 +491,6 @@ pub type BinOp = Spanned<BinOp_>;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum UnOp {
- /// The `box` operator
- UnUniq,
  /// The `*` operator for dereferencing
  UnDeref,
  /// The `!` operator for logical inversion
@@ -595,8 +593,8 @@ impl fmt::Debug for Expr {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Expr_ {
- /// First expr is the place; second expr is the value.
- ExprBox(Option<P<Expr>>, P<Expr>),
+ /// A `box x` expression.
+ ExprBox(P<Expr>),
  /// An array (`[a, b, c, d]`)
  ExprVec(Vec<P<Expr>>),
  /// A function call

src/librustc_front/lowering.rs

@@ -605,7 +605,6 @@ pub fn lower_constness(c: Constness) -> hir::Constness {
 
 pub fn lower_unop(u: UnOp) -> hir::UnOp {
  match u {
- UnUniq => hir::UnUniq,
  UnDeref => hir::UnDeref,
  UnNot => hir::UnNot,
  UnNeg => hir::UnNeg,
@@ -694,8 +693,8 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  P(hir::Expr {
  id: e.id,
  node: match e.node {
- ExprBox(ref p, ref e) => {
- hir::ExprBox(p.as_ref().map(|e| lower_expr(e)), lower_expr(e))
+ ExprBox(ref e) => {
+ hir::ExprBox(lower_expr(e))
  }
  ExprVec(ref exprs) => {
  hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect())
@@ -818,6 +817,7 @@ pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
  ExprParen(ref ex) => {
  return lower_expr(ex);
  }
+ ExprInPlace(..) |
  ExprIfLet(..) |
  ExprWhileLet(..) |
  ExprForLoop(..) |

src/librustc_front/print/pprust.rs

@@ -1182,16 +1182,6 @@ impl<'a> State<'a> {
  Ok(())
  }
 
- fn print_expr_box(&mut self,
- place: &Option<P<hir::Expr>>,
- expr: &hir::Expr) -> io::Result<()> {
- try!(word(&mut self.s, "box"));
- try!(word(&mut self.s, "("));
- try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
- try!(self.word_space(")"));
- self.print_expr(expr)
- }
-
  fn print_expr_vec(&mut self, exprs: &[P<hir::Expr>]) -> io::Result<()> {
  try!(self.ibox(indent_unit));
  try!(word(&mut self.s, "["));
@@ -1311,8 +1301,9 @@ impl<'a> State<'a> {
  try!(self.ibox(indent_unit));
  try!(self.ann.pre(self, NodeExpr(expr)));
  match expr.node {
- hir::ExprBox(ref place, ref expr) => {
- try!(self.print_expr_box(place, &**expr));
+ hir::ExprBox(ref expr) => {
+ try!(self.word_space("box"));
+ try!(self.print_expr(expr));
  }
  hir::ExprVec(ref exprs) => {
  try!(self.print_expr_vec(&exprs[..]));

src/librustc_front/util.rs

@@ -128,10 +128,9 @@ pub fn is_by_value_unop(u: UnOp) -> bool {
 
 pub fn unop_to_string(op: UnOp) -> &'static str {
  match op {
- UnUniq => "box() ",
- UnDeref => "*",
- UnNot => "!",
- UnNeg => "-",
+ UnDeref => "*",
+ UnNot => "!",
+ UnNeg => "-",
  }
 }
 

src/librustc_front/visit.rs

@@ -722,8 +722,7 @@ pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>
 
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
  match expression.node {
- ExprBox(ref place, ref subexpression) => {
- place.as_ref().map(|e|visitor.visit_expr(&**e));
+ ExprBox(ref subexpression) => {
  visitor.visit_expr(&**subexpression)
  }
  ExprVec(ref subexpressions) => {

src/librustc_lint/unused.rs

@@ -442,7 +442,7 @@ impl LintPass for UnusedAllocation {
 impl LateLintPass for UnusedAllocation {
  fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
  match e.node {
- hir::ExprUnary(hir::UnUniq, _) => (),
+ hir::ExprBox(_) => {}
  _ => return
  }
 

src/librustc_mir/build/expr/as_rvalue.rs

@@ -67,7 +67,7 @@ impl<H:Hair> Builder<H> {
  let arg = unpack!(block = this.as_operand(block, arg));
  block.and(Rvalue::UnaryOp(op, arg))
  }
- ExprKind::Box { place: _, value } => {
+ ExprKind::Box { value } => {
  let value = this.hir.mirror(value);
  let value_ty = value.ty.clone();
  let result = this.temp(value_ty.clone());

src/librustc_mir/hair.rs

@@ -171,7 +171,7 @@ pub struct Expr<H:Hair> {
 #[derive(Clone, Debug)]
 pub enum ExprKind<H:Hair> {
  Scope { extent: H::CodeExtent, value: ExprRef<H> },
- Box { place: Option<ExprRef<H>>, value: ExprRef<H> },
+ Box { value: ExprRef<H> },
  Call { fun: ExprRef<H>, args: Vec<ExprRef<H>> },
  Deref { arg: ExprRef<H> }, // NOT overloaded!
  Binary { op: BinOp, lhs: ExprRef<H>, rhs: ExprRef<H> }, // NOT overloaded!

src/librustc_mir/tcx/expr.rs

@@ -140,11 +140,6 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  }
  }
 
- hir::ExprUnary(hir::UnOp::UnUniq, ref arg) => {
- assert!(!cx.tcx.is_method_call(self.id));
- ExprKind::Box { place: None, value: arg.to_ref() }
- }
-
  hir::ExprUnary(op, ref arg) => {
  if cx.tcx.is_method_call(self.id) {
  overloaded_operator(cx, self, ty::MethodCall::expr(self.id),
@@ -154,10 +149,10 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  let op = match op {
  hir::UnOp::UnNot => UnOp::Not,
  hir::UnOp::UnNeg => UnOp::Neg,
- hir::UnOp::UnUniq | hir::UnOp::UnDeref => {
+ hir::UnOp::UnDeref => {
  cx.tcx.sess.span_bug(
  self.span,
-&format!("operator should have been handled elsewhere {:?}", op));
+"UnDeref should have been handled elsewhere");
  }
  };
  ExprKind::Unary { op: op, arg: arg.to_ref() }
@@ -296,8 +291,8 @@ impl<'a,'tcx:'a> Mirror<Cx<'a,'tcx>> for &'tcx hir::Expr {
  name: Field::Indexed(ident.node) },
  hir::ExprCast(ref source, _) =>
  ExprKind::Cast { source: source.to_ref() },
- hir::ExprBox(ref place, ref value) =>
- ExprKind::Box { place: place.to_ref(), value: value.to_ref() },
+ hir::ExprBox(ref value) =>
+ ExprKind::Box { value: value.to_ref() },
  hir::ExprVec(ref fields) =>
  ExprKind::Vec { fields: fields.to_ref() },
  hir::ExprTup(ref fields) =>

src/librustc_trans/trans/consts.rs

@@ -564,10 +564,10 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
  let is_float = ty.is_fp();
  unsafe { match u {
- hir::UnUniq | hir::UnDeref => const_deref(cx, te, ty).0,
- hir::UnNot => llvm::LLVMConstNot(te),
- hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
- hir::UnNeg => llvm::LLVMConstNeg(te),
+ hir::UnDeref  => const_deref(cx, te, ty).0,
+ hir::UnNot => llvm::LLVMConstNot(te),
+ hir::UnNeg if is_float => llvm::LLVMConstFNeg(te),
+ hir::UnNeg => llvm::LLVMConstNeg(te),
  } }
  },
  hir::ExprField(ref base, field) => {

src/librustc_trans/trans/debuginfo/create_scope_map.rs

@@ -325,9 +325,7 @@ fn walk_expr(cx: &CrateContext,
  hir::ExprTupField(ref sub_exp, _) =>
  walk_expr(cx, &**sub_exp, scope_stack, scope_map),
 
- hir::ExprBox(ref place, ref sub_expr) => {
- place.as_ref().map(
- |e| walk_expr(cx, &**e, scope_stack, scope_map));
+ hir::ExprBox(ref sub_expr) => {
  walk_expr(cx, &**sub_expr, scope_stack, scope_map);
  }
 

src/librustc_trans/trans/expr.rs

@@ -673,7 +673,7 @@ fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  hir::ExprIndex(ref base, ref idx) => {
  trans_index(bcx, expr, &**base, &**idx, MethodCall::expr(expr.id))
  }
- hir::ExprBox(_, ref contents) => {
+ hir::ExprBox(ref contents) => {
  // Special case for `Box<T>`
  let box_ty = expr_ty(bcx, expr);
  let contents_ty = expr_ty(bcx, &**contents);
@@ -1649,9 +1649,6 @@ fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
  };
  immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
  }
- hir::UnUniq => {
- trans_uniq_expr(bcx, expr, un_ty, sub_expr, expr_ty(bcx, sub_expr))
- }
  hir::UnDeref => {
  let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
  deref_once(bcx, expr, datum, method_call)
@@ -2769,24 +2766,11 @@ fn expr_kind(tcx: &ty::ctxt, expr: &hir::Expr) -> ExprKind {
 
  hir::ExprLit(_) | // Note: LitStr is carved out above
  hir::ExprUnary(..) |
- hir::ExprBox(None, _) |
+ hir::ExprBox(_) |
  hir::ExprAddrOf(..) |
  hir::ExprBinary(..) |
  hir::ExprCast(..) => {
  ExprKind::RvalueDatum
  }
-
- hir::ExprBox(Some(ref place), _) => {
- // Special case `Box<T>` for now:
- let def_id = match tcx.def_map.borrow().get(&place.id) {
- Some(def) => def.def_id(),
- None => panic!("no def for place"),
- };
- if tcx.lang_items.exchange_heap() == Some(def_id) {
- ExprKind::RvalueDatum
- } else {
- ExprKind::RvalueDps
- }
- }
  }
 }