Auto merge of #65804 - Centril:rollup-arlxgch, r=Centril

Rollup of 9 pull requests

Successful merges:

 - #64639 (Stabilize `#[non_exhaustive]` (RFC 2008))
 - #65074 (Fix the start/end byte positions in the compiler JSON output)
 - #65315 (Intern place projection)
 - #65685 (Fix check of `statx` and handle EPERM)
 - #65731 (Prevent unnecessary allocation in PathBuf::set_extension.)
 - #65740 (Fix default "disable-shortcuts" feature value)
 - #65787 (move panictry! to where it is used.)
 - #65789 (move Attribute::with_desugared_doc to librustdoc)
 - #65790 (move report_invalid_macro_expansion_item to item.rs)

Failed merges:

r? @ghost

src/doc/unstable-book/src/language-features/non-exhaustive.md

@@ -1,76 +0,0 @@
-# `non_exhaustive`
-
-The tracking issue for this feature is: [#44109]
-
-[#44109]: https://github.com/rust-lang/rust/issues/44109
-
-------------------------
-
-The `non_exhaustive` gate allows you to use the `#[non_exhaustive]` attribute
-on structs, enums and enum variants. When applied within a crate, users of the
-crate will need to use the `_` pattern when matching enums and use the `..`
-pattern when matching structs. Enum variants cannot be matched against.
-Structs and enum variants marked as `non_exhaustive` will not be able to
-be created normally outside of the defining crate. This is demonstrated
-below:
-
-```rust,ignore (pseudo-Rust)
-use std::error::Error as StdError;
-
-#[non_exhaustive]
-pub enum Error {
-    Message(String),
-    Other,
-}
-impl StdError for Error {
-    fn description(&self) -> &str {
-        // This will not error, despite being marked as non_exhaustive, as this
-        // enum is defined within the current crate, it can be matched
-        // exhaustively.
-        match *self {
-            Message(ref s) => s,
-            Other => "other or unknown error",
-        }
-    }
-}
-```
-
-```rust,ignore (pseudo-Rust)
-use mycrate::Error;
-
-// This will not error as the non_exhaustive Error enum has been matched with
-// a wildcard.
-match error {
-    Message(ref s) => ...,
-    Other => ...,
-    _ => ...,
-}
-```
-
-```rust,ignore (pseudo-Rust)
-#[non_exhaustive]
-pub struct Config {
-    pub window_width: u16,
-    pub window_height: u16,
-}
-
-// We can create structs as normal within the defining crate when marked as
-// non_exhaustive.
-let config = Config { window_width: 640, window_height: 480 };
-
-// We can match structs exhaustively when within the defining crate.
-if let Ok(Config { window_width, window_height }) = load_config() {
-    // ...
-}
-```
-
-```rust,ignore (pseudo-Rust)
-use mycrate::Config;
-
-// We cannot create a struct like normal if it has been marked as
-// non_exhaustive.
-let config = Config { window_width: 640, window_height: 480 };
-// By adding the `..` we can match the config as below outside of the crate
-// when marked non_exhaustive.
-let &Config { window_width, window_height, .. } = config;
-```

src/libcore/lib.rs

@@ -121,7 +121,7 @@
 #![feature(hexagon_target_feature)]
 #![feature(const_int_conversion)]
 #![feature(const_transmute)]
-#![feature(non_exhaustive)]
+#![cfg_attr(bootstrap, feature(non_exhaustive))]
 #![feature(structural_match)]
 #![feature(abi_unadjusted)]
 #![feature(adx_target_feature)]

src/libproc_macro/lib.rs

@@ -25,7 +25,7 @@
 #![feature(extern_types)]
 #![feature(in_band_lifetimes)]
 #![feature(optin_builtin_traits)]
-#![feature(non_exhaustive)]
+#![cfg_attr(bootstrap, feature(non_exhaustive))]
 #![feature(rustc_attrs)]
 #![feature(specialization)]
 

src/librustc/error_codes.rs

@@ -2105,8 +2105,6 @@ on something other than a struct or enum.
 Examples of erroneous code:
 
 ```compile_fail,E0701
-# #![feature(non_exhaustive)]
-
 #[non_exhaustive]
 trait Foo { }
 ```

src/librustc/ich/impls_syntax.rs

@@ -425,6 +425,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
             ref lines,
             ref multibyte_chars,
             ref non_narrow_chars,
+            ref normalized_pos,
         } = *self;
 
         (name_hash as u64).hash_stable(hcx, hasher);
@@ -453,6 +454,12 @@ impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
         for &char_pos in non_narrow_chars.iter() {
             stable_non_narrow_char(char_pos, start_pos).hash_stable(hcx, hasher);
         }
+
+        normalized_pos.len().hash_stable(hcx, hasher);
+        for &char_pos in normalized_pos.iter() {
+            stable_normalized_pos(char_pos, start_pos).hash_stable(hcx, hasher);
+        }
+
     }
 }
 
@@ -482,6 +489,18 @@ fn stable_non_narrow_char(swc: ::syntax_pos::NonNarrowChar,
     (pos.0 - source_file_start.0, width as u32)
 }
 
+fn stable_normalized_pos(np: ::syntax_pos::NormalizedPos,
+                         source_file_start: ::syntax_pos::BytePos)
+                         -> (u32, u32) {
+    let ::syntax_pos::NormalizedPos {
+        pos,
+        diff
+    } = np;
+
+    (pos.0 - source_file_start.0, diff)
+}
+
+
 impl<'tcx> HashStable<StableHashingContext<'tcx>> for feature_gate::Features {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'tcx>, hasher: &mut StableHasher) {
         // Unfortunately we cannot exhaustively list fields here, since the

src/librustc/lib.rs

@@ -41,7 +41,7 @@
 #![feature(overlapping_marker_traits)]
 #![feature(extern_types)]
 #![feature(nll)]
-#![feature(non_exhaustive)]
+#![cfg_attr(bootstrap, feature(non_exhaustive))]
 #![feature(optin_builtin_traits)]
 #![feature(option_expect_none)]
 #![feature(range_is_empty)]

src/librustc/mir/mod.rs

@@ -15,8 +15,7 @@ use crate::ty::layout::VariantIdx;
 use crate::ty::print::{FmtPrinter, Printer};
 use crate::ty::subst::{Subst, SubstsRef};
 use crate::ty::{
-    self, AdtDef, CanonicalUserTypeAnnotations, Region, Ty, TyCtxt,
-    UserTypeAnnotationIndex,
+    self, AdtDef, CanonicalUserTypeAnnotations, List, Region, Ty, TyCtxt, UserTypeAnnotationIndex,
 };
 
 use polonius_engine::Atom;
@@ -1712,15 +1711,17 @@ impl Debug for Statement<'_> {
 /// A path to a value; something that can be evaluated without
 /// changing or disturbing program state.
 #[derive(
-    Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
+    Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, HashStable,
 )]
 pub struct Place<'tcx> {
     pub base: PlaceBase<'tcx>,
 
     /// projection out of a place (access a field, deref a pointer, etc)
-    pub projection: Box<[PlaceElem<'tcx>]>,
+    pub projection: &'tcx List<PlaceElem<'tcx>>,
 }
 
+impl<'tcx> rustc_serialize::UseSpecializedDecodable for Place<'tcx> {}
+
 #[derive(
     Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
 )]
@@ -1824,6 +1825,8 @@ impl<V, T> ProjectionElem<V, T> {
 /// and the index is a local.
 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
 
+impl<'tcx> Copy for PlaceElem<'tcx> { }
+
 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
 #[cfg(target_arch = "x86_64")]
 static_assert_size!(PlaceElem<'_>, 16);
@@ -1846,50 +1849,11 @@ pub struct PlaceRef<'a, 'tcx> {
 }
 
 impl<'tcx> Place<'tcx> {
-    // FIXME change this back to a const when projection is a shared slice.
-    //
-    // pub const RETURN_PLACE: Place<'tcx> = Place {
-    //     base: PlaceBase::Local(RETURN_PLACE),
-    //     projection: &[],
-    // };
+    // FIXME change this to a const fn by also making List::empty a const fn.
     pub fn return_place() -> Place<'tcx> {
         Place {
             base: PlaceBase::Local(RETURN_PLACE),
-            projection: Box::new([]),
-        }
-    }
-
-    pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
-        self.elem(ProjectionElem::Field(f, ty))
-    }
-
-    pub fn deref(self) -> Place<'tcx> {
-        self.elem(ProjectionElem::Deref)
-    }
-
-    pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx) -> Place<'tcx> {
-        self.elem(ProjectionElem::Downcast(
-            Some(adt_def.variants[variant_index].ident.name),
-            variant_index,
-        ))
-    }
-
-    pub fn downcast_unnamed(self, variant_index: VariantIdx) -> Place<'tcx> {
-        self.elem(ProjectionElem::Downcast(None, variant_index))
-    }
-
-    pub fn index(self, index: Local) -> Place<'tcx> {
-        self.elem(ProjectionElem::Index(index))
-    }
-
-    pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
-        // FIXME(spastorino): revisit this again once projection is not a Box<[T]> anymore
-        let mut projection = self.projection.into_vec();
-        projection.push(elem);
-
-        Place {
-            base: self.base,
-            projection: projection.into_boxed_slice(),
+            projection: List::empty(),
         }
     }
 
@@ -1906,15 +1870,15 @@ impl<'tcx> Place<'tcx> {
     //
     // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
     pub fn local_or_deref_local(&self) -> Option<Local> {
-        match self {
-            Place {
-                base: PlaceBase::Local(local),
-                projection: box [],
+        match self.as_ref() {
+            PlaceRef {
+                base: &PlaceBase::Local(local),
+                projection: &[],
             } |
-            Place {
-                base: PlaceBase::Local(local),
-                projection: box [ProjectionElem::Deref],
-            } => Some(*local),
+            PlaceRef {
+                base: &PlaceBase::Local(local),
+                projection: &[ProjectionElem::Deref],
+            } => Some(local),
             _ => None,
         }
     }
@@ -1922,10 +1886,7 @@ impl<'tcx> Place<'tcx> {
     /// If this place represents a local variable like `_X` with no
     /// projections, return `Some(_X)`.
     pub fn as_local(&self) -> Option<Local> {
-        match self {
-            Place { projection: box [], base: PlaceBase::Local(l) } => Some(*l),
-            _ => None,
-        }
+        self.as_ref().as_local()
     }
 
     pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
@@ -1940,7 +1901,7 @@ impl From<Local> for Place<'_> {
     fn from(local: Local) -> Self {
         Place {
             base: local.into(),
-            projection: Box::new([]),
+            projection: List::empty(),
         }
     }
 }
@@ -1969,6 +1930,15 @@ impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
             _ => None,
         }
     }
+
+    /// If this place represents a local variable like `_X` with no
+    /// projections, return `Some(_X)`.
+    pub fn as_local(&self) -> Option<Local> {
+        match self {
+            PlaceRef { base: PlaceBase::Local(l), projection: [] } => Some(*l),
+            _ => None,
+        }
+    }
 }
 
 impl Debug for Place<'_> {
@@ -3182,6 +3152,17 @@ impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
     }
 }
 
+impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
+        let v = self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>();
+        folder.tcx().intern_place_elems(&v)
+    }
+
+    fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
+        self.iter().any(|t| t.visit_with(visitor))
+    }
+}
+
 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
     fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         Static {

src/librustc/mir/visit.rs

@@ -784,6 +784,8 @@ macro_rules! make_mir_visitor {
 
 macro_rules! visit_place_fns {
     (mut) => (
+        fn tcx<'a>(&'a self) -> TyCtxt<'tcx>;
+
         fn super_place(
             &mut self,
             place: &mut Place<'tcx>,
@@ -793,19 +795,21 @@ macro_rules! visit_place_fns {
             self.visit_place_base(&mut place.base, context, location);
 
             if let Some(new_projection) = self.process_projection(&place.projection) {
-                place.projection = new_projection;
+                place.projection = self.tcx().intern_place_elems(&new_projection);
             }
         }
 
         fn process_projection(
             &mut self,
             projection: &'a [PlaceElem<'tcx>],
-        ) -> Option<Box<[PlaceElem<'tcx>]>> {
+        ) -> Option<Vec<PlaceElem<'tcx>>> {
             let mut projection = Cow::Borrowed(projection);
 
             for i in 0..projection.len() {
                 if let Some(elem) = projection.get(i) {
                     if let Some(elem) = self.process_projection_elem(elem) {
+                        // This converts the borrowed projection into `Cow::Owned(_)` and returns a
+                        // clone of the projection so we can mutate and reintern later.
                         let vec = projection.to_mut();
                         vec[i] = elem;
                     }
@@ -814,7 +818,7 @@ macro_rules! visit_place_fns {
 
             match projection {
                 Cow::Borrowed(_) => None,
-                Cow::Owned(vec) => Some(vec.into_boxed_slice()),
+                Cow::Owned(vec) => Some(vec),
             }
         }
 

src/librustc/ty/codec.rs

@@ -13,9 +13,9 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_serialize::{Decodable, Decoder, Encoder, Encodable, opaque};
 use std::hash::Hash;
 use std::intrinsics;
-use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::{self, List, Ty, TyCtxt};
 use crate::ty::subst::SubstsRef;
-use crate::mir::interpret::Allocation;
+use crate::mir::{self, interpret::Allocation};
 use syntax_pos::Span;
 
 /// The shorthand encoding uses an enum's variant index `usize`
@@ -218,6 +218,18 @@ where
     Ok(tcx.mk_substs((0..len).map(|_| Decodable::decode(decoder)))?)
 }
 
+#[inline]
+pub fn decode_place<D>(decoder: &mut D) -> Result<mir::Place<'tcx>, D::Error>
+where
+    D: TyDecoder<'tcx>,
+{
+    let base: mir::PlaceBase<'tcx> = Decodable::decode(decoder)?;
+    let len = decoder.read_usize()?;
+    let projection: &'tcx List<mir::PlaceElem<'tcx>> =
+        decoder.tcx().mk_place_elems((0..len).map(|_| Decodable::decode(decoder)))?;
+    Ok(mir::Place { base, projection })
+}
+
 #[inline]
 pub fn decode_region<D>(decoder: &mut D) -> Result<ty::Region<'tcx>, D::Error>
 where
@@ -413,6 +425,15 @@ macro_rules! implement_ty_decoder {
                 }
             }
 
+            impl<$($typaram),*> SpecializedDecoder<$crate::mir::Place<'tcx>>
+            for $DecoderName<$($typaram),*> {
+                fn specialized_decode(
+                    &mut self
+                ) -> Result<$crate::mir::Place<'tcx>, Self::Error> {
+                    decode_place(self)
+                }
+            }
+
             impl<$($typaram),*> SpecializedDecoder<ty::Region<'tcx>>
             for $DecoderName<$($typaram),*> {
                 fn specialized_decode(&mut self) -> Result<ty::Region<'tcx>, Self::Error> {

src/librustc/ty/context.rs

@@ -1,3 +1,4 @@
+// ignore-tidy-filelength
 //! Type context book-keeping.
 
 use crate::arena::Arena;
@@ -21,7 +22,7 @@ use crate::middle::cstore::EncodedMetadata;
 use crate::middle::lang_items;
 use crate::middle::resolve_lifetime::{self, ObjectLifetimeDefault};
 use crate::middle::stability;
-use crate::mir::{Body, interpret, ProjectionKind, Promoted};
+use crate::mir::{Body, Field, interpret, Local, Place, PlaceElem, ProjectionKind, Promoted};
 use crate::mir::interpret::{ConstValue, Allocation, Scalar};
 use crate::ty::subst::{GenericArg, InternalSubsts, SubstsRef, Subst};
 use crate::ty::ReprOptions;
@@ -106,6 +107,7 @@ pub struct CtxtInterners<'tcx> {
     goal: InternedSet<'tcx, GoalKind<'tcx>>,
     goal_list: InternedSet<'tcx, List<Goal<'tcx>>>,
     projs: InternedSet<'tcx, List<ProjectionKind>>,
+    place_elems: InternedSet<'tcx, List<PlaceElem<'tcx>>>,
     const_: InternedSet<'tcx, Const<'tcx>>,
 }
 
@@ -124,6 +126,7 @@ impl<'tcx> CtxtInterners<'tcx> {
             goal: Default::default(),
             goal_list: Default::default(),
             projs: Default::default(),
+            place_elems: Default::default(),
             const_: Default::default(),
         }
     }
@@ -2142,6 +2145,13 @@ impl<'tcx> Borrow<[ProjectionKind]>
     }
 }
 
+impl<'tcx> Borrow<[PlaceElem<'tcx>]>
+    for Interned<'tcx, List<PlaceElem<'tcx>>> {
+    fn borrow(&self) -> &[PlaceElem<'tcx>] {
+        &self.0[..]
+    }
+}
+
 impl<'tcx> Borrow<RegionKind> for Interned<'tcx, RegionKind> {
     fn borrow(&self) -> &RegionKind {
         &self.0
@@ -2242,7 +2252,8 @@ slice_interners!(
     predicates: _intern_predicates(Predicate<'tcx>),
     clauses: _intern_clauses(Clause<'tcx>),
     goal_list: _intern_goals(Goal<'tcx>),
-    projs: _intern_projs(ProjectionKind)
+    projs: _intern_projs(ProjectionKind),
+    place_elems: _intern_place_elems(PlaceElem<'tcx>)
 );
 
 impl<'tcx> TyCtxt<'tcx> {
@@ -2584,6 +2595,48 @@ impl<'tcx> TyCtxt<'tcx> {
         self.mk_ty(Opaque(def_id, substs))
     }
 
+    pub fn mk_place_field(self, place: Place<'tcx>, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
+        self.mk_place_elem(place, PlaceElem::Field(f, ty))
+    }
+
+    pub fn mk_place_deref(self, place: Place<'tcx>) -> Place<'tcx> {
+        self.mk_place_elem(place, PlaceElem::Deref)
+    }
+
+    pub fn mk_place_downcast(
+        self,
+        place: Place<'tcx>,
+        adt_def: &'tcx AdtDef,
+        variant_index: VariantIdx,
+    ) -> Place<'tcx> {
+        self.mk_place_elem(
+            place,
+            PlaceElem::Downcast(Some(adt_def.variants[variant_index].ident.name), variant_index),
+        )
+    }
+
+    pub fn mk_place_downcast_unnamed(
+        self,
+        place: Place<'tcx>,
+        variant_index: VariantIdx,
+    ) -> Place<'tcx> {
+        self.mk_place_elem(place, PlaceElem::Downcast(None, variant_index))
+    }
+
+    pub fn mk_place_index(self, place: Place<'tcx>, index: Local) -> Place<'tcx> {
+        self.mk_place_elem(place, PlaceElem::Index(index))
+    }
+
+    /// This method copies `Place`'s projection, add an element and reintern it. Should not be used
+    /// to build a full `Place` it's just a convenient way to grab a projection and modify it in
+    /// flight.
+    pub fn mk_place_elem(self, place: Place<'tcx>, elem: PlaceElem<'tcx>) -> Place<'tcx> {
+        let mut projection = place.projection.to_vec();
+        projection.push(elem);
+
+        Place { base: place.base, projection: self.intern_place_elems(&projection) }
+    }
+
     pub fn intern_existential_predicates(self, eps: &[ExistentialPredicate<'tcx>])
         -> &'tcx List<ExistentialPredicate<'tcx>> {
         assert!(!eps.is_empty());
@@ -2628,6 +2681,14 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
+    pub fn intern_place_elems(self, ts: &[PlaceElem<'tcx>]) -> &'tcx List<PlaceElem<'tcx>> {
+        if ts.len() == 0 {
+            List::empty()
+        } else {
+            self._intern_place_elems(ts)
+        }
+    }
+
     pub fn intern_canonical_var_infos(self, ts: &[CanonicalVarInfo]) -> CanonicalVarInfos<'tcx> {
         if ts.len() == 0 {
             List::empty()
@@ -2690,6 +2751,11 @@ impl<'tcx> TyCtxt<'tcx> {
         iter.intern_with(|xs| self.intern_substs(xs))
     }
 
+    pub fn mk_place_elems<I: InternAs<[PlaceElem<'tcx>],
+                          &'tcx List<PlaceElem<'tcx>>>>(self, iter: I) -> I::Output {
+        iter.intern_with(|xs| self.intern_place_elems(xs))
+    }
+
     pub fn mk_substs_trait(self,
                      self_ty: Ty<'tcx>,
                      rest: &[GenericArg<'tcx>])

src/librustc_codegen_ssa/mir/analyze.rs

@@ -191,10 +191,7 @@ impl<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
                     location: Location) {
         debug!("visit_assign(place={:?}, rvalue={:?})", place, rvalue);
 
-        if let mir::Place {
-            base: mir::PlaceBase::Local(index),
-            projection: box [],
-        } = *place {
+        if let Some(index) = place.as_local() {
             self.assign(index, location);
             let decl_span = self.fx.mir.local_decls[index].source_info.span;
             if !self.fx.rvalue_creates_operand(rvalue, decl_span) {

src/librustc_codegen_ssa/mir/block.rs

@@ -2,7 +2,7 @@ use rustc_index::vec::Idx;
 use rustc::middle::lang_items;
 use rustc::ty::{self, Ty, TypeFoldable, Instance};
 use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, FnTypeExt};
-use rustc::mir::{self, Place, PlaceBase, Static, StaticKind};
+use rustc::mir::{self, PlaceBase, Static, StaticKind};
 use rustc::mir::interpret::PanicInfo;
 use rustc_target::abi::call::{ArgType, FnType, PassMode};
 use rustc_target::spec::abi::Abi;
@@ -630,30 +630,21 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 // checked by const-qualification, which also
                 // promotes any complex rvalues to constants.
                 if i == 2 && intrinsic.unwrap().starts_with("simd_shuffle") {
-                    match *arg {
+                    match arg {
                         // The shuffle array argument is usually not an explicit constant,
                         // but specified directly in the code. This means it gets promoted
                         // and we can then extract the value by evaluating the promoted.
-                        mir::Operand::Copy(
-                            Place {
-                                base: PlaceBase::Static(box Static {
+                        mir::Operand::Copy(place) | mir::Operand::Move(place) => {
+                            if let mir::PlaceRef {
+                                base:
+                                    &PlaceBase::Static(box Static {
                                         kind: StaticKind::Promoted(promoted, _),
                                         ty,
                                         def_id: _,
                                     }),
-                                projection: box [],
-                            }
-                        ) |
-                        mir::Operand::Move(
-                            Place {
-                                base: PlaceBase::Static(box Static {
-                                    kind: StaticKind::Promoted(promoted, _),
-                                    ty,
-                                    def_id: _,
-                                }),
-                                projection: box [],
-                            }
-                        ) => {
+                                projection: &[],
+                            } = place.as_ref()
+                            {
                                 let param_env = ty::ParamEnv::reveal_all();
                                 let cid = mir::interpret::GlobalId {
                                     instance: self.instance,
@@ -670,13 +661,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                                     val: Immediate(llval),
                                     layout: bx.layout_of(ty),
                                 };
-
-                        }
-                        mir::Operand::Copy(_) |
-                        mir::Operand::Move(_) => {
+                            } else {
                                 span_bug!(span, "shuffle indices must be constant");
                             }
-                        mir::Operand::Constant(ref constant) => {
+                        }
+
+                        mir::Operand::Constant(constant) => {
                             let c = self.eval_mir_constant(constant);
                             let (llval, ty) = self.simd_shuffle_indices(
                                 &bx,
@@ -1117,10 +1107,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         if fn_ret.is_ignore() {
             return ReturnDest::Nothing;
         }
-        let dest = if let mir::Place {
-            base: mir::PlaceBase::Local(index),
-            projection: box [],
-        } = *dest {
+        let dest = if let Some(index) = dest.as_local() {
             match self.locals[index] {
                 LocalRef::Place(dest) => dest,
                 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
@@ -1178,10 +1165,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         src: &mir::Operand<'tcx>,
         dst: &mir::Place<'tcx>
     ) {
-        if let mir::Place {
-            base: mir::PlaceBase::Local(index),
-            projection: box [],
-        } = *dst {
+        if let Some(index) = dst.as_local() {
             match self.locals[index] {
                 LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
                 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),

src/librustc_codegen_ssa/mir/rvalue.rs

@@ -530,10 +530,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     ) -> Bx::Value {
         // ZST are passed as operands and require special handling
         // because codegen_place() panics if Local is operand.
-        if let mir::Place {
-            base: mir::PlaceBase::Local(index),
-            projection: box [],
-        } = *place {
+        if let Some(index) = place.as_local() {
             if let LocalRef::Operand(Some(op)) = self.locals[index] {
                 if let ty::Array(_, n) = op.layout.ty.kind {
                     let n = n.eval_usize(bx.cx().tcx(), ty::ParamEnv::reveal_all());

src/librustc_codegen_ssa/mir/statement.rs

@@ -17,11 +17,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         self.set_debug_loc(&mut bx, statement.source_info);
         match statement.kind {
             mir::StatementKind::Assign(box(ref place, ref rvalue)) => {
-                if let mir::Place {
-                    base: mir::PlaceBase::Local(index),
-                    projection: box [],
-                } = place {
-                    match self.locals[*index] {
+                if let Some(index) = place.as_local() {
+                    match self.locals[index] {
                         LocalRef::Place(cg_dest) => {
                             self.codegen_rvalue(bx, cg_dest, rvalue)
                         }
@@ -30,7 +27,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         }
                         LocalRef::Operand(None) => {
                             let (mut bx, operand) = self.codegen_rvalue_operand(bx, rvalue);
-                            if let Some(name) = self.mir.local_decls[*index].name {
+                            if let Some(name) = self.mir.local_decls[index].name {
                                 match operand.val {
                                     OperandValue::Ref(x, ..) |
                                     OperandValue::Immediate(x) => {
@@ -44,7 +41,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                                     }
                                 }
                             }
-                            self.locals[*index] = LocalRef::Operand(Some(operand));
+                            self.locals[index] = LocalRef::Operand(Some(operand));
                             bx
                         }
                         LocalRef::Operand(Some(op)) => {

src/librustc_metadata/decoder.rs

@@ -1319,6 +1319,7 @@ impl<'a, 'tcx> CrateMetadata {
                                       mut lines,
                                       mut multibyte_chars,
                                       mut non_narrow_chars,
+                                      mut normalized_pos,
                                       name_hash,
                                       .. } = source_file_to_import;
 
@@ -1338,6 +1339,9 @@ impl<'a, 'tcx> CrateMetadata {
             for swc in &mut non_narrow_chars {
                 *swc = *swc - start_pos;
             }
+            for np in &mut normalized_pos {
+                np.pos = np.pos - start_pos;
+            }
 
             let local_version = local_source_map.new_imported_source_file(name,
                                                                    name_was_remapped,
@@ -1347,7 +1351,8 @@ impl<'a, 'tcx> CrateMetadata {
                                                                    source_length,
                                                                    lines,
                                                                    multibyte_chars,
-                                                                   non_narrow_chars);
+                                                                   non_narrow_chars,
+                                                                   normalized_pos);
             debug!("CrateMetaData::imported_source_files alloc \
                     source_file {:?} original (start_pos {:?} end_pos {:?}) \
                     translated (start_pos {:?} end_pos {:?})",

src/librustc_mir/borrow_check/borrow_set.rs

@@ -315,10 +315,7 @@ impl<'a, 'tcx> GatherBorrows<'a, 'tcx> {
         //    TEMP = &foo
         //
         // so extract `temp`.
-        let temp = if let &mir::Place {
-            base: mir::PlaceBase::Local(temp),
-            projection: box [],
-        } = assigned_place {
+        let temp = if let Some(temp) = assigned_place.as_local() {
             temp
         } else {
             span_bug!(

src/librustc_mir/borrow_check/conflict_errors.rs

@@ -239,11 +239,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         );
                     }
                 }
-                let span = if let Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                } = place {
-                    let decl = &self.body.local_decls[*local];
+                let span = if let Some(local) = place.as_local() {
+                    let decl = &self.body.local_decls[local];
                     Some(decl.source_info.span)
                 } else {
                     None
@@ -611,7 +608,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     projection,
                 } = first_borrowed_place;
 
-                let mut cursor = &**projection;
+                let mut cursor = projection.as_ref();
                 while let [proj_base @ .., elem] = cursor {
                     cursor = proj_base;
 
@@ -635,7 +632,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     projection,
                 } = second_borrowed_place;
 
-                let mut cursor = &**projection;
+                let mut cursor = projection.as_ref();
                 while let [proj_base @ .., elem] = cursor {
                     cursor = proj_base;
 
@@ -710,10 +707,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             _ => drop_span,
         };
 
+        let root_place_projection = self.infcx.tcx.intern_place_elems(root_place.projection);
+
         if self.access_place_error_reported
             .contains(&(Place {
                 base: root_place.base.clone(),
-                projection: root_place.projection.to_vec().into_boxed_slice(),
+                projection: root_place_projection,
             }, borrow_span))
         {
             debug!(
@@ -726,7 +725,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         self.access_place_error_reported
             .insert((Place {
                 base: root_place.base.clone(),
-                projection: root_place.projection.to_vec().into_boxed_slice(),
+                projection: root_place_projection,
             }, borrow_span));
 
         if let StorageDeadOrDrop::Destructor(dropped_ty) =
@@ -1124,11 +1123,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         };
 
         let (place_desc, note) = if let Some(place_desc) = opt_place_desc {
-            let local_kind = match borrow.borrowed_place {
-                Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                } => {
+            let local_kind = if let Some(local) = borrow.borrowed_place.as_local() {
                 match self.body.local_kind(local) {
                     LocalKind::ReturnPointer
                     | LocalKind::Temp => bug!("temporary or return pointer with a name"),
@@ -1142,8 +1137,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         "function parameter "
                     }
                 }
-                }
-                _ => "local data ",
+            } else {
+                "local data "
             };
             (
                 format!("{}`{}`", local_kind, place_desc),
@@ -1480,10 +1475,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         assigned_span: Span,
         err_place: &Place<'tcx>,
     ) {
-        let (from_arg, local_decl) = if let Place {
-            base: PlaceBase::Local(local),
-            projection: box [],
-        } = *err_place {
+        let (from_arg, local_decl) = if let Some(local) = err_place.as_local() {
             if let LocalKind::Arg = self.body.local_kind(local) {
                 (true, Some(&self.body.local_decls[local]))
             } else {
@@ -1643,11 +1635,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 reservation
             );
             // Check that the initial assignment of the reserve location is into a temporary.
-            let mut target = *match reservation {
-                Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                } if self.body.local_kind(*local) == LocalKind::Temp => local,
+            let mut target = match reservation.as_local() {
+                Some(local) if self.body.local_kind(local) == LocalKind::Temp => local,
                 _ => return None,
             };
 
@@ -1659,15 +1648,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     "annotate_argument_and_return_for_borrow: target={:?} stmt={:?}",
                     target, stmt
                 );
-                if let StatementKind::Assign(
-                    box(
-                        Place {
-                            base: PlaceBase::Local(assigned_to),
-                            projection: box [],
-                        },
-                        rvalue
-                    )
-                ) = &stmt.kind {
+                if let StatementKind::Assign(box(place, rvalue)) = &stmt.kind {
+                    if let Some(assigned_to) = place.as_local() {
                         debug!(
                             "annotate_argument_and_return_for_borrow: assigned_to={:?} \
                              rvalue={:?}",
@@ -1692,7 +1674,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 );
 
                                 // Find the local from the operand.
-                            let assigned_from_local = match assigned_from.local_or_deref_local() {
+                                let assigned_from_local = match assigned_from.local_or_deref_local()
+                                {
                                     Some(local) => local,
                                     None => continue,
                                 };
@@ -1715,13 +1698,13 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                     annotated_closure, assigned_from_local, assigned_to
                                 );
 
-                            if *assigned_to == mir::RETURN_PLACE {
+                                if assigned_to == mir::RETURN_PLACE {
                                     // If it was assigned directly into the return place, then
                                     // return now.
                                     return annotated_closure;
                                 } else {
                                     // Otherwise, update the target.
-                                target = *assigned_to;
+                                    target = assigned_to;
                                 }
                             }
 
@@ -1771,7 +1754,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                              assigned_from_local={:?} assigned_to={:?}",
                             assigned_from_local, assigned_to
                         );
-                    if *assigned_to == mir::RETURN_PLACE {
+                        if assigned_to == mir::RETURN_PLACE {
                             // If it was then return the annotated closure if there was one,
                             // else, annotate this function.
                             return annotated_closure.or_else(fallback);
@@ -1779,7 +1762,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
                         // If we didn't assign into the return place, then we just update
                         // the target.
-                    target = *assigned_to;
+                        target = assigned_to;
+                    }
                 }
             }
 
@@ -1790,14 +1774,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 target, terminator
             );
             if let TerminatorKind::Call {
-                destination: Some((Place {
-                    base: PlaceBase::Local(assigned_to),
-                    projection: box [],
-                }, _)),
+                destination: Some((place, _)),
                 args,
                 ..
             } = &terminator.kind
             {
+                if let Some(assigned_to) = place.as_local() {
                     debug!(
                         "annotate_argument_and_return_for_borrow: assigned_to={:?} args={:?}",
                         assigned_to, args
@@ -1820,13 +1802,14 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 assigned_from_local,
                             );
 
-                        if *assigned_to == mir::RETURN_PLACE && assigned_from_local == target {
+                            if assigned_to == mir::RETURN_PLACE && assigned_from_local == target {
                                 return annotated_closure.or_else(fallback);
                             }
                         }
                     }
                 }
             }
+        }
 
         // If we haven't found an assignment into the return place, then we need not add
         // any annotations.

src/librustc_mir/borrow_check/error_reporting.rs

@@ -838,12 +838,15 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             .get(location.statement_index)
         {
             Some(&Statement {
-                kind: StatementKind::Assign(box(Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                }, _)),
+                kind: StatementKind::Assign(box(ref place, _)),
                 ..
-            }) => local,
+            }) => {
+                if let Some(local) = place.as_local() {
+                    local
+                } else {
+                    return OtherUse(use_span);
+                }
+            }
             _ => return OtherUse(use_span),
         };
 

src/librustc_mir/borrow_check/mod.rs

@@ -1133,15 +1133,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         // Special case: you can assign a immutable local variable
         // (e.g., `x = ...`) so long as it has never been initialized
         // before (at this point in the flow).
-        if let Place {
-            base: PlaceBase::Local(local),
-            projection: box [],
-        } = place_span.0 {
-            if let Mutability::Not = self.body.local_decls[*local].mutability {
+        if let Some(local) = place_span.0.as_local() {
+            if let Mutability::Not = self.body.local_decls[local].mutability {
                 // check for reassignments to immutable local variables
                 self.check_if_reassignment_to_immutable_state(
                     location,
-                    *local,
+                    local,
                     place_span,
                     flow_state,
                 );
@@ -1288,14 +1285,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         // captures of a closure are copied/moved directly
         // when generating MIR.
         match *operand {
-            Operand::Move(Place {
-                base: PlaceBase::Local(local),
-                projection: box [],
-            }) |
-            Operand::Copy(Place {
-                base: PlaceBase::Local(local),
-                projection: box [],
-            }) if self.body.local_decls[local].is_user_variable.is_none() => {
+            Operand::Move(ref place) | Operand::Copy(ref place) => {
+                match place.as_local() {
+                    Some(local) if self.body.local_decls[local].is_user_variable.is_none() => {
                         if self.body.local_decls[local].ty.is_mutable_ptr() {
                             // The variable will be marked as mutable by the borrow.
                             return;
@@ -1331,16 +1323,19 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         let stmt = &bbd.statements[loc.statement_index];
                         debug!("temporary assigned in: stmt={:?}", stmt);
 
-                if let StatementKind::Assign(box(_, Rvalue::Ref(_, _, ref source))) = stmt.kind {
+                        if let StatementKind::Assign(box (_, Rvalue::Ref(_, _, ref source))) =
+                            stmt.kind
+                        {
                             propagate_closure_used_mut_place(self, source);
                         } else {
-                    bug!("closures should only capture user variables \
-                        or references to user variables");
+                            bug!(
+                                "closures should only capture user variables \
+                                 or references to user variables"
+                            );
                         }
                     }
-            Operand::Move(ref place)
-            | Operand::Copy(ref place) => {
-                propagate_closure_used_mut_place(self, place);
+                    _ => propagate_closure_used_mut_place(self, place),
+                }
             }
             Operand::Constant(..) => {}
         }
@@ -1702,7 +1697,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         debug!("check_if_assigned_path_is_moved place: {:?}", place);
 
         // None case => assigning to `x` does not require `x` be initialized.
-        let mut cursor = &*place.projection;
+        let mut cursor = &*place.projection.as_ref();
         while let [proj_base @ .., elem] = cursor {
             cursor = proj_base;
 

src/librustc_mir/borrow_check/move_errors.rs

@@ -89,19 +89,14 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 // If that ever stops being the case, then the ever initialized
                 // flow could be used.
                 if let Some(StatementKind::Assign(
-                    box(
-                        Place {
-                            base: PlaceBase::Local(local),
-                            projection: box [],
-                        },
-                        Rvalue::Use(Operand::Move(move_from))
-                    )
+                    box(place, Rvalue::Use(Operand::Move(move_from)))
                 )) = self.body.basic_blocks()[location.block]
                     .statements
                     .get(location.statement_index)
                     .map(|stmt| &stmt.kind)
                 {
-                    let local_decl = &self.body.local_decls[*local];
+                    if let Some(local) = place.as_local() {
+                        let local_decl = &self.body.local_decls[local];
                         // opt_match_place is the
                         // match_span is the span of the expression being matched on
                         // match *x.y { ... }        match_place is Some(*x.y)
@@ -122,7 +117,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                 kind,
                                 original_path,
                                 move_from,
-                            *local,
+                                local,
                                 opt_match_place,
                                 match_span,
                                 stmt_source_info.span,
@@ -130,6 +125,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                             return;
                         }
                     }
+                }
 
                 let move_spans = self.move_spans(original_path.as_ref(), location);
                 grouped_errors.push(GroupedMoveError::OtherIllegalMove {
@@ -307,11 +303,11 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let upvar_field = self.prefixes(move_place.as_ref(), PrefixSet::All)
             .find_map(|p| self.is_upvar_field_projection(p));
 
-        let deref_base = match &deref_target_place.projection {
-            box [proj_base @ .., ProjectionElem::Deref] => {
+        let deref_base = match deref_target_place.projection.as_ref() {
+            &[ref proj_base @ .., ProjectionElem::Deref] => {
                 PlaceRef {
                     base: &deref_target_place.base,
-                    projection: proj_base,
+                    projection: &proj_base,
                 }
             }
             _ => bug!("deref_target_place is not a deref projection"),

src/librustc_mir/borrow_check/mutability_errors.rs

@@ -49,10 +49,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 projection: [],
             } => {
                 item_msg = format!("`{}`", access_place_desc.unwrap());
-                if let Place {
-                    base: PlaceBase::Local(_),
-                    projection: box [],
-                } = access_place {
+                if access_place.as_local().is_some() {
                     reason = ", as it is not declared as mutable".to_string();
                 } else {
                     let name = self.body.local_decls[*local]
@@ -153,10 +150,10 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     }),
                 projection: [],
             } => {
-                if let Place {
-                    base: PlaceBase::Static(_),
-                    projection: box [],
-                } = access_place {
+                if let PlaceRef {
+                    base: &PlaceBase::Static(_),
+                    projection: &[],
+                } = access_place.as_ref() {
                     item_msg = format!("immutable static item `{}`", access_place_desc.unwrap());
                     reason = String::new();
                 } else {

src/librustc_mir/borrow_check/nll/constraint_generation.rs

@@ -8,8 +8,8 @@ use rustc::infer::InferCtxt;
 use rustc::mir::visit::TyContext;
 use rustc::mir::visit::Visitor;
 use rustc::mir::{
-    BasicBlock, BasicBlockData, Body, Local, Location, Place, PlaceBase, ProjectionElem, Rvalue,
-    SourceInfo, Statement, StatementKind, Terminator, TerminatorKind, UserTypeProjection,
+    BasicBlock, BasicBlockData, Body, Local, Location, Place, PlaceBase, PlaceRef, ProjectionElem,
+    Rvalue, SourceInfo, Statement, StatementKind, Terminator, TerminatorKind, UserTypeProjection,
 };
 use rustc::ty::fold::TypeFoldable;
 use rustc::ty::{self, RegionVid, Ty};
@@ -211,14 +211,14 @@ impl<'cx, 'cg, 'tcx> ConstraintGeneration<'cx, 'cg, 'tcx> {
             // - if it's a deeper projection, we have to filter which
             //   of the borrows are killed: the ones whose `borrowed_place`
             //   conflicts with the `place`.
-            match place {
-                Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
+            match place.as_ref() {
+                PlaceRef {
+                    base: &PlaceBase::Local(local),
+                    projection: &[],
                 } |
-                Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [ProjectionElem::Deref],
+                PlaceRef {
+                    base: &PlaceBase::Local(local),
+                    projection: &[ProjectionElem::Deref],
                 } => {
                     debug!(
                         "Recording `killed` facts for borrows of local={:?} at location={:?}",
@@ -229,21 +229,21 @@ impl<'cx, 'cg, 'tcx> ConstraintGeneration<'cx, 'cg, 'tcx> {
                         all_facts,
                         self.borrow_set,
                         self.location_table,
-                        local,
+                        &local,
                         location,
                     );
                 }
 
-                Place {
-                    base: PlaceBase::Static(_),
+                PlaceRef {
+                    base: &PlaceBase::Static(_),
                     ..
                 } => {
                     // Ignore kills of static or static mut variables.
                 }
 
-                Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [.., _],
+                PlaceRef {
+                    base: &PlaceBase::Local(local),
+                    projection: &[.., _],
                 } => {
                     // Kill conflicting borrows of the innermost local.
                     debug!(
@@ -252,7 +252,7 @@ impl<'cx, 'cg, 'tcx> ConstraintGeneration<'cx, 'cg, 'tcx> {
                         local, location
                     );
 
-                    if let Some(borrow_indices) = self.borrow_set.local_map.get(local) {
+                    if let Some(borrow_indices) = self.borrow_set.local_map.get(&local) {
                         for &borrow_index in borrow_indices {
                             let places_conflict = places_conflict::places_conflict(
                                 self.infcx.tcx,

src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs

@@ -6,8 +6,8 @@ use crate::borrow_check::nll::region_infer::{Cause, RegionName};
 use crate::borrow_check::nll::ConstraintDescription;
 use crate::borrow_check::{MirBorrowckCtxt, WriteKind};
 use rustc::mir::{
-    CastKind, ConstraintCategory, FakeReadCause, Local, Location, Body, Operand, Place, PlaceBase,
-    Rvalue, Statement, StatementKind, TerminatorKind,
+    CastKind, ConstraintCategory, FakeReadCause, Local, Location, Body, Operand, Place, Rvalue,
+    Statement, StatementKind, TerminatorKind,
 };
 use rustc::ty::{self, TyCtxt};
 use rustc::ty::adjustment::{PointerCast};
@@ -273,12 +273,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 let mut should_note_order = false;
                 if body.local_decls[local].name.is_some() {
                     if let Some((WriteKind::StorageDeadOrDrop, place)) = kind_place {
-                        if let Place {
-                            base: PlaceBase::Local(borrowed_local),
-                            projection: box [],
-                        } = place {
-                             if body.local_decls[*borrowed_local].name.is_some()
-                                && local != *borrowed_local
+                        if let Some(borrowed_local) = place.as_local() {
+                             if body.local_decls[borrowed_local].name.is_some()
+                                && local != borrowed_local
                             {
                                 should_note_order = true;
                             }
@@ -494,22 +491,19 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         // Just point to the function, to reduce the chance of overlapping spans.
                         let function_span = match func {
                             Operand::Constant(c) => c.span,
-                            Operand::Copy(Place {
-                                base: PlaceBase::Local(l),
-                                projection: box [],
-                            }) |
-                            Operand::Move(Place {
-                                base: PlaceBase::Local(l),
-                                projection: box [],
-                            }) => {
-                                let local_decl = &self.body.local_decls[*l];
+                            Operand::Copy(place) |
+                            Operand::Move(place) => {
+                                if let Some(l) = place.as_local() {
+                                    let local_decl = &self.body.local_decls[l];
                                     if local_decl.name.is_none() {
                                         local_decl.source_info.span
                                     } else {
                                         span
                                     }
+                                } else {
+                                    span
+                                }
                             }
-                            _ => span,
                         };
                         return (LaterUseKind::Call, function_span);
                     } else {
@@ -542,16 +536,16 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         // it which simplifies the termination logic.
         let mut queue = vec![location];
         let mut target = if let Some(&Statement {
-            kind: StatementKind::Assign(box(Place {
-                base: PlaceBase::Local(local),
-                projection: box [],
-            }, _)),
+            kind: StatementKind::Assign(box(ref place, _)),
             ..
-        }) = stmt
-        {
+        }) = stmt {
+            if let Some(local) = place.as_local() {
                 local
             } else {
                 return false;
+            }
+        } else {
+            return false;
         };
 
         debug!(
@@ -582,18 +576,14 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         // If we see a use, we should check whether it is our data, and if so
                         // update the place that we're looking for to that new place.
                         Rvalue::Use(operand) => match operand {
-                            Operand::Copy(Place {
-                                base: PlaceBase::Local(from),
-                                projection: box [],
-                            })
-                            | Operand::Move(Place {
-                                base: PlaceBase::Local(from),
-                                projection: box [],
-                            })
-                                if *from == target =>
-                            {
+                            Operand::Copy(place)
+                            | Operand::Move(place) => {
+                                if let Some(from) = place.as_local() {
+                                    if from == target {
                                         target = into;
                                     }
+                                }
+                            }
                             _ => {}
                         },
                         // If we see a unsized cast, then if it is our data we should check
@@ -601,16 +591,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         Rvalue::Cast(
                             CastKind::Pointer(PointerCast::Unsize), operand, ty
                         ) => match operand {
-                            Operand::Copy(Place {
-                                base: PlaceBase::Local(from),
-                                projection: box [],
-                            })
-                            | Operand::Move(Place {
-                                base: PlaceBase::Local(from),
-                                projection: box [],
-                            })
-                                if *from == target =>
-                            {
+                            Operand::Copy(place)
+                            | Operand::Move(place) => {
+                                if let Some(from) = place.as_local() {
+                                    if from == target {
                                         debug!("was_captured_by_trait_object: ty={:?}", ty);
                                         // Check the type for a trait object.
                                         return match ty.kind {
@@ -624,6 +608,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                             _ => false,
                                         };
                                     }
+                                }
+                                return false;
+                            }
                             _ => return false,
                         },
                         _ => {}
@@ -638,25 +625,23 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 debug!("was_captured_by_trait_object: terminator={:?}", terminator);
 
                 if let TerminatorKind::Call {
-                    destination: Some((Place {
-                        base: PlaceBase::Local(dest),
-                        projection: box [],
-                    }, block)),
+                    destination: Some((place, block)),
                     args,
                     ..
-                } = &terminator.kind
-                {
+                } = &terminator.kind {
+                    if let Some(dest) = place.as_local() {
                         debug!(
                             "was_captured_by_trait_object: target={:?} dest={:?} args={:?}",
                             target, dest, args
                         );
                         // Check if one of the arguments to this function is the target place.
                         let found_target = args.iter().any(|arg| {
-                        if let Operand::Move(Place {
-                            base: PlaceBase::Local(potential),
-                            projection: box [],
-                        }) = arg {
-                            *potential == target
+                            if let Operand::Move(place) = arg {
+                                if let Some(potential) = place.as_local() {
+                                    potential == target
+                                } else {
+                                    false
+                                }
                             } else {
                                 false
                             }
@@ -664,11 +649,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
                         // If it is, follow this to the next block and update the target.
                         if found_target {
-                        target = *dest;
+                            target = dest;
                             queue.push(block.start_location());
                         }
                     }
                 }
+            }
 
             debug!("was_captured_by_trait: queue={:?}", queue);
         }

src/librustc_mir/borrow_check/nll/renumber.rs

@@ -1,5 +1,5 @@
 use rustc::ty::subst::SubstsRef;
-use rustc::ty::{self, Ty, TypeFoldable};
+use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
 use rustc::mir::{Body, Location, PlaceElem, Promoted};
 use rustc::mir::visit::{MutVisitor, TyContext};
 use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
@@ -54,6 +54,10 @@ impl<'a, 'tcx> NLLVisitor<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.infcx.tcx
+    }
+
     fn visit_ty(&mut self, ty: &mut Ty<'tcx>, ty_context: TyContext) {
         debug!("visit_ty(ty={:?}, ty_context={:?})", ty, ty_context);
 

src/librustc_mir/borrow_check/nll/type_check/mod.rs

@@ -480,13 +480,13 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
 
         if place.projection.is_empty() {
             if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
-                let is_promoted = match place {
-                    Place {
-                        base: PlaceBase::Static(box Static {
+                let is_promoted = match place.as_ref() {
+                    PlaceRef {
+                        base: &PlaceBase::Static(box Static {
                             kind: StaticKind::Promoted(..),
                             ..
                         }),
-                        projection: box [],
+                        projection: &[],
                     } => true,
                     _ => false,
                 };
@@ -1366,11 +1366,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 // they are not caused by the user, but rather artifacts
                 // of lowering. Assignments to other sorts of places *are* interesting
                 // though.
-                let category = match *place {
-                    Place {
-                        base: PlaceBase::Local(RETURN_PLACE),
-                        projection: box [],
-                    } => if let BorrowCheckContext {
+                let category = match place.as_local() {
+                    Some(RETURN_PLACE) => if let BorrowCheckContext {
                         universal_regions:
                             UniversalRegions {
                                 defining_ty: DefiningTy::Const(def_id, _),
@@ -1386,10 +1383,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     } else {
                         ConstraintCategory::Return
                     },
-                    Place {
-                        base: PlaceBase::Local(l),
-                        projection: box [],
-                    } if !body.local_decls[l].is_user_variable.is_some() => {
+                    Some(l) if !body.local_decls[l].is_user_variable.is_some() => {
                         ConstraintCategory::Boring
                     }
                     _ => ConstraintCategory::Assignment,
@@ -1675,11 +1669,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             Some((ref dest, _target_block)) => {
                 let dest_ty = dest.ty(body, tcx).ty;
                 let dest_ty = self.normalize(dest_ty, term_location);
-                let category = match *dest {
-                    Place {
-                        base: PlaceBase::Local(RETURN_PLACE),
-                        projection: box [],
-                    } => {
+                let category = match dest.as_local() {
+                    Some(RETURN_PLACE) => {
                         if let BorrowCheckContext {
                             universal_regions:
                                 UniversalRegions {
@@ -1698,10 +1689,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             ConstraintCategory::Return
                         }
                     }
-                    Place {
-                        base: PlaceBase::Local(l),
-                        projection: box [],
-                    } if !body.local_decls[l].is_user_variable.is_some() => {
+                    Some(l) if !body.local_decls[l].is_user_variable.is_some() => {
                         ConstraintCategory::Boring
                     }
                     _ => ConstraintCategory::Assignment,
@@ -2432,7 +2420,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             location, borrow_region, borrowed_place
         );
 
-        let mut cursor = &*borrowed_place.projection;
+        let mut cursor = borrowed_place.projection.as_ref();
         while let [proj_base @ .., elem] = cursor {
             cursor = proj_base;
 

src/librustc_mir/borrow_check/places_conflict.rs

@@ -64,14 +64,8 @@ pub(super) fn borrow_conflicts_with_place<'tcx>(
 
     // This Local/Local case is handled by the more general code below, but
     // it's so common that it's a speed win to check for it first.
-    if let Place {
-        base: PlaceBase::Local(l1),
-        projection: box [],
-    } = borrow_place {
-        if let PlaceRef {
-            base: PlaceBase::Local(l2),
-            projection: [],
-        } = access_place {
+    if let Some(l1) = borrow_place.as_local() {
+        if let Some(l2) = access_place.as_local() {
             return l1 == l2;
         }
     }

src/librustc_mir/borrow_check/used_muts.rs

@@ -1,7 +1,5 @@
 use rustc::mir::visit::{PlaceContext, Visitor};
-use rustc::mir::{
-    Local, Location, Place, PlaceBase, Statement, StatementKind, TerminatorKind
-};
+use rustc::mir::{Local, Location, Place, PlaceBase, Statement, StatementKind, TerminatorKind};
 
 use rustc_data_structures::fx::FxHashSet;
 
@@ -118,10 +116,7 @@ impl<'visit, 'cx, 'tcx> Visitor<'tcx> for GatherUsedMutsVisitor<'visit, 'cx, 'tc
                     "assignment of {:?} to {:?}, adding {:?} to used mutable set",
                     path.place, local, path.place
                 );
-                if let Place {
-                    base: PlaceBase::Local(user_local),
-                    projection: box [],
-                } = path.place {
+                if let Some(user_local) = path.place.as_local() {
                     self.mbcx.used_mut.insert(user_local);
                 }
             }

src/librustc_mir/build/expr/as_place.rs

@@ -6,7 +6,7 @@ use crate::build::{BlockAnd, BlockAndExtension, Builder};
 use crate::hair::*;
 use rustc::mir::interpret::{PanicInfo::BoundsCheck};
 use rustc::mir::*;
-use rustc::ty::{CanonicalUserTypeAnnotation, Ty, Variance};
+use rustc::ty::{CanonicalUserTypeAnnotation, Ty, TyCtxt, Variance};
 
 use rustc_index::vec::Idx;
 
@@ -23,10 +23,10 @@ struct PlaceBuilder<'tcx> {
 }
 
 impl PlaceBuilder<'tcx> {
-    fn into_place(self) -> Place<'tcx> {
+    fn into_place(self, tcx: TyCtxt<'tcx>) -> Place<'tcx> {
         Place {
             base: self.base,
-            projection: self.projection.into_boxed_slice(),
+            projection: tcx.intern_place_elems(&self.projection),
         }
     }
 
@@ -73,7 +73,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         M: Mirror<'tcx, Output = Expr<'tcx>>,
     {
         let place_builder = unpack!(block = self.as_place_builder(block, expr));
-        block.and(place_builder.into_place())
+        block.and(place_builder.into_place(self.hir.tcx()))
     }
 
     /// This is used when constructing a compound `Place`, so that we can avoid creating
@@ -96,7 +96,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         M: Mirror<'tcx, Output = Expr<'tcx>>,
     {
         let place_builder = unpack!(block = self.as_read_only_place_builder(block, expr));
-        block.and(place_builder.into_place())
+        block.and(place_builder.into_place(self.hir.tcx()))
     }
 
     /// This is used when constructing a compound `Place`, so that we can avoid creating
@@ -165,7 +165,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     Mutability::Not,
                 ));
 
-                let slice = place_builder.clone().into_place();
+                let slice = place_builder.clone().into_place(this.hir.tcx());
                 // bounds check:
                 let (len, lt) = (
                     this.temp(usize_ty.clone(), expr_span),
@@ -225,7 +225,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         }
                     );
 
-                    let place = place_builder.clone().into_place();
+                    let place = place_builder.clone().into_place(this.hir.tcx());
                     this.cfg.push(
                         block,
                         Statement {

src/librustc_mir/build/expr/as_rvalue.rs

@@ -139,7 +139,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // initialize the box contents:
                 unpack!(
                     block = this.into(
-                        &Place::from(result).deref(),
+                        &this.hir.tcx().mk_place_deref(Place::from(result)),
                         block, value
                     )
                 );
@@ -296,8 +296,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         .zip(field_types.into_iter())
                         .map(|(n, ty)| match fields_map.get(&n) {
                             Some(v) => v.clone(),
-                            None => this.consume_by_copy_or_move(base.clone().field(n, ty)),
-                        }).collect()
+                            None => this.consume_by_copy_or_move(this.hir.tcx().mk_place_field(
+                                base.clone(),
+                                n,
+                                ty,
+                            )),
+                        })
+                        .collect()
                 } else {
                     field_names
                         .iter()
@@ -397,8 +402,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             let val_fld = Field::new(0);
             let of_fld = Field::new(1);
 
-            let val = result_value.clone().field(val_fld, ty);
-            let of = result_value.field(of_fld, bool_ty);
+            let tcx = self.hir.tcx();
+            let val = tcx.mk_place_field(result_value.clone(), val_fld, ty);
+            let of = tcx.mk_place_field(result_value, of_fld, bool_ty);
 
             let err = PanicInfo::Overflow(op);
 
@@ -496,14 +502,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
         let arg_place = unpack!(block = this.as_place(block, arg));
 
-        let mutability = match arg_place {
-            Place {
-                base: PlaceBase::Local(local),
-                projection: box [],
+        let mutability = match arg_place.as_ref() {
+            PlaceRef {
+                base: &PlaceBase::Local(local),
+                projection: &[],
             } => this.local_decls[local].mutability,
-            Place {
-                base: PlaceBase::Local(local),
-                projection: box [ProjectionElem::Deref],
+            PlaceRef {
+                base: &PlaceBase::Local(local),
+                projection: &[ProjectionElem::Deref],
             } => {
                 debug_assert!(
                     this.local_decls[local].is_ref_for_guard(),
@@ -511,13 +517,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 );
                 this.local_decls[local].mutability
             }
-            Place {
+            PlaceRef {
                 ref base,
-                projection: box [ref proj_base @ .., ProjectionElem::Field(upvar_index, _)],
+                projection: &[ref proj_base @ .., ProjectionElem::Field(upvar_index, _)],
             }
-            | Place {
+            | PlaceRef {
                 ref base,
-                projection: box [
+                projection: &[
                     ref proj_base @ ..,
                     ProjectionElem::Field(upvar_index, _),
                     ProjectionElem::Deref

src/librustc_mir/build/expr/into.rs

@@ -235,7 +235,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     });
                     let ptr_temp = Place::from(ptr_temp);
                     let block = unpack!(this.into(&ptr_temp, block, ptr));
-                    this.into(&ptr_temp.deref(), block, val)
+                    this.into(&this.hir.tcx().mk_place_deref(ptr_temp), block, val)
                 } else {
                     let args: Vec<_> = args
                         .into_iter()

src/librustc_mir/build/matches/mod.rs

@@ -948,7 +948,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
                     fake_borrows.insert(Place {
                         base: source.base.clone(),
-                        projection: proj_base.to_vec().into_boxed_slice(),
+                        projection: self.hir.tcx().intern_place_elems(proj_base),
                     });
                 }
             }
@@ -1293,7 +1293,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // Insert a Shallow borrow of the prefixes of any fake borrows.
         for place in fake_borrows
         {
-            let mut cursor = &*place.projection;
+            let mut cursor = place.projection.as_ref();
             while let [proj_base @ .., elem] = cursor {
                 cursor = proj_base;
 
@@ -1488,7 +1488,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     BorrowKind::Shallow,
                     Place {
                         base: place.base.clone(),
-                        projection: place.projection.to_vec().into_boxed_slice(),
+                        projection: tcx.intern_place_elems(place.projection),
                     },
                 );
                 self.cfg.push_assign(

src/librustc_mir/build/matches/simplify.rs

@@ -166,7 +166,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     }
                 });
                 if irrefutable {
-                    let place = match_pair.place.downcast(adt_def, variant_index);
+                    let place = tcx.mk_place_downcast(match_pair.place, adt_def, variant_index);
                     candidate.match_pairs.extend(self.field_match_pairs(place, subpatterns));
                     Ok(())
                 } else {
@@ -191,7 +191,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
 
             PatKind::Deref { ref subpattern } => {
-                let place = match_pair.place.deref();
+                let place = tcx.mk_place_deref(match_pair.place);
                 candidate.match_pairs.push(MatchPair::new(place, subpattern));
                 Ok(())
             }

src/librustc_mir/build/matches/test.rs

@@ -743,19 +743,18 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         candidate: &mut Candidate<'pat, 'tcx>,
     ) {
         let match_pair = candidate.match_pairs.remove(match_pair_index);
+        let tcx = self.hir.tcx();
 
         // So, if we have a match-pattern like `x @ Enum::Variant(P1, P2)`,
         // we want to create a set of derived match-patterns like
         // `(x as Variant).0 @ P1` and `(x as Variant).1 @ P1`.
         let elem = ProjectionElem::Downcast(
             Some(adt_def.variants[variant_index].ident.name), variant_index);
-        let downcast_place = match_pair.place.elem(elem); // `(x as Variant)`
-        let consequent_match_pairs =
-            subpatterns.iter()
-                       .map(|subpattern| {
+        let downcast_place = tcx.mk_place_elem(match_pair.place, elem); // `(x as Variant)`
+        let consequent_match_pairs = subpatterns.iter().map(|subpattern| {
             // e.g., `(x as Variant).0`
-                           let place = downcast_place.clone().field(subpattern.field,
-                                                                      subpattern.pattern.ty);
+            let place =
+                tcx.mk_place_field(downcast_place.clone(), subpattern.field, subpattern.pattern.ty);
             // e.g., `(x as Variant).0 @ P1`
             MatchPair::new(place, &subpattern.pattern)
         });

src/librustc_mir/build/matches/util.rs

@@ -6,14 +6,19 @@ use std::u32;
 use std::convert::TryInto;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
-    pub fn field_match_pairs<'pat>(&mut self,
+    pub fn field_match_pairs<'pat>(
+        &mut self,
         place: Place<'tcx>,
-                                   subpatterns: &'pat [FieldPat<'tcx>])
-                                   -> Vec<MatchPair<'pat, 'tcx>> {
-        subpatterns.iter()
+        subpatterns: &'pat [FieldPat<'tcx>],
+    ) -> Vec<MatchPair<'pat, 'tcx>> {
+        subpatterns
+            .iter()
             .map(|fieldpat| {
-                       let place = place.clone().field(fieldpat.field,
-                                                       fieldpat.pattern.ty);
+                let place = self.hir.tcx().mk_place_field(
+                    place.clone(),
+                    fieldpat.field,
+                    fieldpat.pattern.ty,
+                );
                 MatchPair::new(place, &fieldpat.pattern)
             })
             .collect()
@@ -27,6 +32,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                      suffix: &'pat [Pat<'tcx>]) {
         let min_length = prefix.len() + suffix.len();
         let min_length = min_length.try_into().unwrap();
+        let tcx = self.hir.tcx();
 
         match_pairs.extend(
             prefix.iter()
@@ -37,13 +43,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                           min_length,
                           from_end: false,
                       };
-                      let place = place.clone().elem(elem);
+                      let place = tcx.mk_place_elem(place.clone(), elem);
                       MatchPair::new(place, subpattern)
                   })
         );
 
         if let Some(subslice_pat) = opt_slice {
-            let subslice = place.clone().elem(ProjectionElem::Subslice {
+            let subslice = tcx.mk_place_elem(place.clone(),ProjectionElem::Subslice {
                 from: prefix.len() as u32,
                 to: suffix.len() as u32
             });
@@ -60,7 +66,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                           min_length,
                           from_end: true,
                       };
-                      let place = place.clone().elem(elem);
+                      let place = tcx.mk_place_elem(place.clone(), elem);
                       MatchPair::new(place, subpattern)
                   })
         );

src/librustc_mir/build/scope.rs

@@ -926,14 +926,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             // If constants and statics, we don't generate StorageLive for this
             // temporary, so don't try to generate StorageDead for it either.
             _ if self.local_scope().is_none() => (),
-            Operand::Copy(Place {
-                base: PlaceBase::Local(cond_temp),
-                projection: box [],
-            })
-            | Operand::Move(Place {
-                base: PlaceBase::Local(cond_temp),
-                projection: box [],
-            }) => {
+            Operand::Copy(place)
+            | Operand::Move(place) => {
+                if let Some(cond_temp) = place.as_local() {
                     // Manually drop the condition on both branches.
                     let top_scope = self.scopes.scopes.last_mut().unwrap();
                     let top_drop_data = top_scope.drops.pop().unwrap();
@@ -964,8 +959,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     }
 
                     top_scope.invalidate_cache(true, self.is_generator, true);
+                } else {
+                    bug!("Expected as_local_operand to produce a temporary");
+                }
             }
-            _ => bug!("Expected as_local_operand to produce a temporary"),
         }
 
         (true_block, false_block)

src/librustc_mir/dataflow/impls/storage_liveness.rs

@@ -157,11 +157,13 @@ impl<'mir, 'tcx> BitDenotation<'tcx> for RequiresStorage<'mir, 'tcx> {
         // Since `propagate_call_unwind` doesn't exist, we have to kill the
         // destination here, and then gen it again in `propagate_call_return`.
         if let TerminatorKind::Call {
-            destination: Some((Place { base: PlaceBase::Local(local), projection: box [] }, _)),
+            destination: Some((ref place, _)),
             ..
         } = self.body[loc.block].terminator().kind {
+            if let Some(local) = place.as_local() {
                 sets.kill(local);
             }
+        }
         self.check_for_move(sets, loc);
     }
 

src/librustc_mir/dataflow/move_paths/builder.rs

@@ -114,7 +114,7 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
                         BorrowedContent {
                             target_place: Place {
                                 base: place.base.clone(),
-                                projection: proj.to_vec().into_boxed_slice(),
+                                projection: tcx.intern_place_elems(proj),
                             },
                         },
                     ));
@@ -172,7 +172,7 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
                             Some(base),
                             Place {
                                 base: place.base.clone(),
-                                projection: proj.to_vec().into_boxed_slice(),
+                                projection: tcx.intern_place_elems(proj),
                             },
                         );
                         ent.insert(path);
@@ -274,7 +274,7 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
                     // Box starts out uninitialized - need to create a separate
                     // move-path for the interior so it will be separate from
                     // the exterior.
-                    self.create_move_path(&place.clone().deref());
+                    self.create_move_path(&self.builder.tcx.mk_place_deref(place.clone()));
                     self.gather_init(place.as_ref(), InitKind::Shallow);
                 } else {
                     self.gather_init(place.as_ref(), InitKind::Deep);

src/librustc_mir/dataflow/move_paths/mod.rs

@@ -327,7 +327,7 @@ impl<'tcx> MoveData<'tcx> {
     pub fn base_local(&self, mut mpi: MovePathIndex) -> Option<Local> {
         loop {
             let path = &self.move_paths[mpi];
-            if let Place { base: PlaceBase::Local(l), projection: box [] } = path.place {
+            if let Some(l) = path.place.as_local() {
                 return Some(l);
             }
             if let Some(parent) = path.parent {

src/librustc_mir/shim.rs

@@ -117,7 +117,7 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> &'tcx
 
     run_passes(tcx, &mut result, instance, None, MirPhase::Const, &[
         &add_moves_for_packed_drops::AddMovesForPackedDrops,
-        &no_landing_pads::NoLandingPads,
+        &no_landing_pads::NoLandingPads::new(tcx),
         &remove_noop_landing_pads::RemoveNoopLandingPads,
         &simplify::SimplifyCfg::new("make_shim"),
         &add_call_guards::CriticalCallEdges,
@@ -231,7 +231,7 @@ fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>)
                 tcx,
                 param_env
             };
-            let dropee = dropee_ptr.deref();
+            let dropee = tcx.mk_place_deref(dropee_ptr);
             let resume_block = elaborator.patch.resume_block();
             elaborate_drops::elaborate_drop(
                 &mut elaborator,
@@ -312,7 +312,7 @@ fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -
     let is_copy = self_ty.is_copy_modulo_regions(tcx, param_env, builder.span);
 
     let dest = Place::return_place();
-    let src = Place::from(Local::new(1+0)).deref();
+    let src = tcx.mk_place_deref(Place::from(Local::new(1+0)));
 
     match self_ty.kind {
         _ if is_copy => builder.copy_shim(),
@@ -415,7 +415,7 @@ impl CloneShimBuilder<'tcx> {
     }
 
     fn copy_shim(&mut self) {
-        let rcvr = Place::from(Local::new(1+0)).deref();
+        let rcvr = self.tcx.mk_place_deref(Place::from(Local::new(1+0)));
         let ret_statement = self.make_statement(
             StatementKind::Assign(
                 box(
@@ -561,8 +561,8 @@ impl CloneShimBuilder<'tcx> {
         // BB #2
         // `dest[i] = Clone::clone(src[beg])`;
         // Goto #3 if ok, #5 if unwinding happens.
-        let dest_field = dest.clone().index(beg);
-        let src_field = src.index(beg);
+        let dest_field = self.tcx.mk_place_index(dest.clone(), beg);
+        let src_field = self.tcx.mk_place_index(src, beg);
         self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3),
                              BasicBlock::new(5));
 
@@ -616,7 +616,7 @@ impl CloneShimBuilder<'tcx> {
         // BB #7 (cleanup)
         // `drop(dest[beg])`;
         self.block(vec![], TerminatorKind::Drop {
-            location: dest.index(beg),
+            location: self.tcx.mk_place_index(dest, beg),
             target: BasicBlock::new(8),
             unwind: None,
         }, true);
@@ -648,9 +648,9 @@ impl CloneShimBuilder<'tcx> {
         let mut previous_field = None;
         for (i, ity) in tys.enumerate() {
             let field = Field::new(i);
-            let src_field = src.clone().field(field, ity);
+            let src_field = self.tcx.mk_place_field(src.clone(), field, ity);
 
-            let dest_field = dest.clone().field(field, ity);
+            let dest_field = self.tcx.mk_place_field(dest.clone(), field, ity);
 
             // #(2i + 1) is the cleanup block for the previous clone operation
             let cleanup_block = self.block_index_offset(1);
@@ -721,14 +721,14 @@ fn build_call_shim<'tcx>(
 
     let rcvr = match rcvr_adjustment {
         Adjustment::Identity => Operand::Move(rcvr_l),
-        Adjustment::Deref => Operand::Copy(rcvr_l.deref()),
+        Adjustment::Deref => Operand::Copy(tcx.mk_place_deref(rcvr_l)),
         Adjustment::DerefMove => {
             // fn(Self, ...) -> fn(*mut Self, ...)
             let arg_ty = local_decls[rcvr_arg].ty;
             debug_assert!(tcx.generics_of(def_id).has_self && arg_ty == tcx.types.self_param);
             local_decls[rcvr_arg].ty = tcx.mk_mut_ptr(arg_ty);
 
-            Operand::Move(rcvr_l.deref())
+            Operand::Move(tcx.mk_place_deref(rcvr_l))
         }
         Adjustment::RefMut => {
             // let rcvr = &mut rcvr;
@@ -772,7 +772,7 @@ fn build_call_shim<'tcx>(
     if let Some(untuple_args) = untuple_args {
         args.extend(untuple_args.iter().enumerate().map(|(i, ity)| {
             let arg_place = Place::from(Local::new(1+1));
-            Operand::Move(arg_place.field(Field::new(i), *ity))
+            Operand::Move(tcx.mk_place_field(arg_place, Field::new(i), *ity))
         }));
     } else {
         args.extend((1..sig.inputs().len()).map(|i| {
@@ -901,6 +901,7 @@ pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> &Body<'_> {
             )),
         AggregateKind::Adt(adt_def, variant_index, substs, None, None),
         source_info,
+        tcx,
     ).collect();
 
     let start_block = BasicBlockData {

src/librustc_mir/transform/check_consts/qualifs.rs

@@ -164,8 +164,8 @@ pub trait Qualif {
 
             Rvalue::Ref(_, _, ref place) => {
                 // Special-case reborrows to be more like a copy of the reference.
-                if let box [proj_base @ .., elem] = &place.projection {
-                    if ProjectionElem::Deref == *elem {
+                if let &[ref proj_base @ .., elem] = place.projection.as_ref() {
+                    if ProjectionElem::Deref == elem {
                         let base_ty = Place::ty_from(&place.base, proj_base, cx.body, cx.tcx).ty;
                         if let ty::Ref(..) = base_ty.kind {
                             return Self::in_place(cx, per_local, PlaceRef {

src/librustc_mir/transform/check_consts/resolver.rs

@@ -56,16 +56,16 @@ where
     fn assign_qualif_direct(&mut self, place: &mir::Place<'tcx>, value: bool) {
         debug_assert!(!place.is_indirect());
 
-        match (value, place) {
-            (true, mir::Place { base: mir::PlaceBase::Local(local), .. }) => {
-                self.qualifs_per_local.insert(*local);
+        match (value, place.as_ref()) {
+            (true, mir::PlaceRef { base: &mir::PlaceBase::Local(local), .. }) => {
+                self.qualifs_per_local.insert(local);
             }
 
             // For now, we do not clear the qualif if a local is overwritten in full by
             // an unqualified rvalue (e.g. `y = 5`). This is to be consistent
             // with aggregates where we overwrite all fields with assignments, which would not
             // get this feature.
-            (false, mir::Place { base: mir::PlaceBase::Local(_local), projection: box [] }) => {
+            (false, mir::PlaceRef { base: &mir::PlaceBase::Local(_local), projection: &[] }) => {
                 // self.qualifs_per_local.remove(*local);
             }
 
@@ -101,13 +101,12 @@ where
 
         // If a local with no projections is moved from (e.g. `x` in `y = x`), record that
         // it no longer needs to be dropped.
-        if let mir::Operand::Move(mir::Place {
-            base: mir::PlaceBase::Local(local),
-            projection: box [],
-        }) = *operand {
+        if let mir::Operand::Move(place) = operand {
+            if let Some(local) = place.as_local() {
                 self.qualifs_per_local.remove(local);
             }
         }
+    }
 
     fn visit_assign(
         &mut self,

src/librustc_mir/transform/check_consts/validation.rs

@@ -244,8 +244,8 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
         if let Rvalue::Ref(_, kind, ref place) = *rvalue {
             // Special-case reborrows to be more like a copy of a reference.
             let mut reborrow_place = None;
-            if let box [proj_base @ .., elem] = &place.projection {
-                if *elem == ProjectionElem::Deref {
+            if let &[ref proj_base @ .., elem] = place.projection.as_ref() {
+                if elem == ProjectionElem::Deref {
                     let base_ty = Place::ty_from(&place.base, proj_base, self.body, self.tcx).ty;
                     if let ty::Ref(..) = base_ty.kind {
                         reborrow_place = Some(proj_base);
@@ -376,12 +376,15 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
             );
 
             if rvalue_has_mut_interior {
-                let is_derived_from_illegal_borrow = match *borrowed_place {
+                let is_derived_from_illegal_borrow = match borrowed_place.as_local() {
                     // If an unprojected local was borrowed and its value was the result of an
                     // illegal borrow, suppress this error and mark the result of this borrow as
                     // illegal as well.
-                    Place { base: PlaceBase::Local(borrowed_local), projection: box [] }
-                        if self.derived_from_illegal_borrow.contains(borrowed_local) => true,
+                    Some(borrowed_local)
+                        if self.derived_from_illegal_borrow.contains(borrowed_local) =>
+                    {
+                        true
+                    }
 
                     // Otherwise proceed normally: check the legality of a mutable borrow in this
                     // context.
@@ -394,7 +397,7 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
                 // FIXME: should we also clear `derived_from_illegal_borrow` when a local is
                 // assigned a new value?
                 if is_derived_from_illegal_borrow {
-                    if let Place { base: PlaceBase::Local(dest), projection: box [] } = *dest {
+                    if let Some(dest) = dest.as_local() {
                         self.derived_from_illegal_borrow.insert(dest);
                     }
                 }
@@ -571,10 +574,7 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
                     return;
                 }
 
-                let needs_drop = if let Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                } = *dropped_place {
+                let needs_drop = if let Some(local) = dropped_place.as_local() {
                     // Use the span where the local was declared as the span of the drop error.
                     err_span = self.body.local_decls[local].source_info.span;
                     self.qualifs.needs_drop.contains(local)

src/librustc_mir/transform/check_unsafety.rs

@@ -406,8 +406,8 @@ impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> {
         place: &Place<'tcx>,
         is_mut_use: bool,
     ) {
-        let mut cursor = &*place.projection;
-        while let [proj_base @ .., elem] = cursor {
+        let mut cursor = place.projection.as_ref();
+        while let &[ref proj_base @ .., elem] = cursor {
             cursor = proj_base;
 
             match elem {

src/librustc_mir/transform/cleanup_post_borrowck.rs

@@ -24,16 +24,22 @@ use crate::transform::{MirPass, MirSource};
 
 pub struct CleanupNonCodegenStatements;
 
-pub struct DeleteNonCodegenStatements;
+pub struct DeleteNonCodegenStatements<'tcx> {
+    tcx: TyCtxt<'tcx>,
+}
 
 impl<'tcx> MirPass<'tcx> for CleanupNonCodegenStatements {
-    fn run_pass(&self, _tcx: TyCtxt<'tcx>, _source: MirSource<'tcx>, body: &mut Body<'tcx>) {
-        let mut delete = DeleteNonCodegenStatements;
+    fn run_pass(&self, tcx: TyCtxt<'tcx>, _source: MirSource<'tcx>, body: &mut Body<'tcx>) {
+        let mut delete = DeleteNonCodegenStatements { tcx };
         delete.visit_body(body);
     }
 }
 
-impl<'tcx> MutVisitor<'tcx> for DeleteNonCodegenStatements {
+impl<'tcx> MutVisitor<'tcx> for DeleteNonCodegenStatements<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_statement(&mut self,
                        statement: &mut Statement<'tcx>,
                        location: Location) {

src/librustc_mir/transform/const_prop.rs

@@ -7,10 +7,9 @@ use std::cell::Cell;
 use rustc::hir::def::DefKind;
 use rustc::hir::def_id::DefId;
 use rustc::mir::{
-    AggregateKind, Constant, Location, Place, PlaceBase, Body, Operand, Rvalue,
-    Local, UnOp, StatementKind, Statement, LocalKind,
-    TerminatorKind, Terminator,  ClearCrossCrate, SourceInfo, BinOp,
-    SourceScope, SourceScopeLocalData, LocalDecl, BasicBlock,
+    AggregateKind, Constant, Location, Place, PlaceBase, Body, Operand, Rvalue, Local, UnOp,
+    StatementKind, Statement, LocalKind, TerminatorKind, Terminator,  ClearCrossCrate, SourceInfo,
+    BinOp, SourceScope, SourceScopeLocalData, LocalDecl, BasicBlock,
 };
 use rustc::mir::visit::{
     Visitor, PlaceContext, MutatingUseContext, MutVisitor, NonMutatingUseContext,
@@ -525,10 +524,12 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             // (e.g. for CTFE) it can never happen. But here in const_prop
             // unknown data is uninitialized, so if e.g. a function argument is unsized
             // and has a reference taken, we get an ICE.
-            Rvalue::Ref(_, _, Place { base: PlaceBase::Local(local), projection: box [] }) => {
-                trace!("checking Ref({:?})", place);
+            Rvalue::Ref(_, _, place_ref) => {
+                trace!("checking Ref({:?})", place_ref);
+
+                if let Some(local) = place_ref.as_local() {
                     let alive =
-                    if let LocalValue::Live(_) = self.ecx.frame().locals[*local].value {
+                        if let LocalValue::Live(_) = self.ecx.frame().locals[local].value {
                             true
                         } else {
                             false
@@ -539,6 +540,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                         return None;
                     }
                 }
+            }
 
             _ => { }
         }
@@ -685,6 +687,10 @@ impl<'tcx> Visitor<'tcx> for CanConstProp {
 }
 
 impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_constant(
         &mut self,
         constant: &mut Constant<'tcx>,
@@ -706,10 +712,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
                 .ty(&self.local_decls, self.tcx)
                 .ty;
             if let Ok(place_layout) = self.tcx.layout_of(self.param_env.and(place_ty)) {
-                if let Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                } = *place {
+                if let Some(local) = place.as_local() {
                     let source = statement.source_info;
                     if let Some(()) = self.const_prop(rval, place_layout, source, place) {
                         if self.can_const_prop[local] {

src/librustc_mir/transform/copy_prop.rs

@@ -19,9 +19,7 @@
 //! (non-mutating) use of `SRC`. These restrictions are conservative and may be relaxed in the
 //! future.
 
-use rustc::mir::{
-    Constant, Local, LocalKind, Location, Place, PlaceBase, Body, Operand, Rvalue, StatementKind
-};
+use rustc::mir::{Constant, Local, LocalKind, Location, Place, Body, Operand, Rvalue, StatementKind};
 use rustc::mir::visit::MutVisitor;
 use rustc::ty::TyCtxt;
 use crate::transform::{MirPass, MirSource};
@@ -92,17 +90,11 @@ impl<'tcx> MirPass<'tcx> for CopyPropagation {
                     };
 
                     // That use of the source must be an assignment.
-                    match statement.kind {
-                        StatementKind::Assign(
-                            box(
-                                Place {
-                                    base: PlaceBase::Local(local),
-                                    projection: box [],
-                                },
-                                Rvalue::Use(ref operand)
-                            )
-                        ) if local == dest_local => {
-                            let maybe_action = match *operand {
+                    match &statement.kind {
+                        StatementKind::Assign(box(place, Rvalue::Use(operand))) => {
+                            if let Some(local) = place.as_local() {
+                                if local == dest_local {
+                                    let maybe_action = match operand {
                                         Operand::Copy(ref src_place) |
                                         Operand::Move(ref src_place) => {
                                             Action::local_copy(&body, &def_use_analysis, src_place)
@@ -115,6 +107,16 @@ impl<'tcx> MirPass<'tcx> for CopyPropagation {
                                         Some(this_action) => action = this_action,
                                         None => continue,
                                     }
+                                } else {
+                                    debug!("  Can't copy-propagate local: source use is not an \
+                                    assignment");
+                                    continue
+                                }
+                            } else {
+                                debug!("  Can't copy-propagate local: source use is not an \
+                                    assignment");
+                                continue
+                            }
                         }
                         _ => {
                             debug!("  Can't copy-propagate local: source use is not an \
@@ -124,7 +126,8 @@ impl<'tcx> MirPass<'tcx> for CopyPropagation {
                     }
                 }
 
-                changed = action.perform(body, &def_use_analysis, dest_local, location) || changed;
+                changed =
+                    action.perform(body, &def_use_analysis, dest_local, location, tcx) || changed;
                 // FIXME(pcwalton): Update the use-def chains to delete the instructions instead of
                 // regenerating the chains.
                 break
@@ -148,31 +151,20 @@ fn eliminate_self_assignments(
         for def in dest_use_info.defs_not_including_drop() {
             let location = def.location;
             if let Some(stmt) = body[location.block].statements.get(location.statement_index) {
-                match stmt.kind {
-                    StatementKind::Assign(
-                        box(
-                            Place {
-                                base: PlaceBase::Local(local),
-                                projection: box [],
-                            },
-                            Rvalue::Use(Operand::Copy(Place {
-                                base: PlaceBase::Local(src_local),
-                                projection: box [],
-                            })),
-                        )
-                    ) |
-                    StatementKind::Assign(
-                        box(
-                            Place {
-                                base: PlaceBase::Local(local),
-                                projection: box [],
-                            },
-                            Rvalue::Use(Operand::Move(Place {
-                                base: PlaceBase::Local(src_local),
-                                projection: box [],
-                            })),
-                        )
-                    ) if local == dest_local && dest_local == src_local => {}
+                match &stmt.kind {
+                    StatementKind::Assign(box (place, Rvalue::Use(Operand::Copy(src_place))))
+                    | StatementKind::Assign(box (place, Rvalue::Use(Operand::Move(src_place)))) => {
+                        if let (Some(local), Some(src_local)) =
+                            (place.as_local(), src_place.as_local())
+                        {
+                            if local == dest_local && dest_local == src_local {
+                            } else {
+                                continue;
+                            }
+                        } else {
+                            continue;
+                        }
+                    }
                     _ => {
                         continue;
                     }
@@ -198,10 +190,7 @@ impl<'tcx> Action<'tcx> {
     fn local_copy(body: &Body<'tcx>, def_use_analysis: &DefUseAnalysis, src_place: &Place<'tcx>)
                   -> Option<Action<'tcx>> {
         // The source must be a local.
-        let src_local = if let Place {
-            base: PlaceBase::Local(local),
-            projection: box [],
-        } = *src_place {
+        let src_local = if let Some(local) = src_place.as_local() {
             local
         } else {
             debug!("  Can't copy-propagate local: source is not a local");
@@ -256,7 +245,8 @@ impl<'tcx> Action<'tcx> {
                body: &mut Body<'tcx>,
                def_use_analysis: &DefUseAnalysis,
                dest_local: Local,
-               location: Location)
+               location: Location,
+               tcx: TyCtxt<'tcx>)
                -> bool {
         match self {
             Action::PropagateLocalCopy(src_local) => {
@@ -280,7 +270,7 @@ impl<'tcx> Action<'tcx> {
                 }
 
                 // Replace all uses of the destination local with the source local.
-                def_use_analysis.replace_all_defs_and_uses_with(dest_local, body, src_local);
+                def_use_analysis.replace_all_defs_and_uses_with(dest_local, body, src_local, tcx);
 
                 // Finally, zap the now-useless assignment instruction.
                 debug!("  Deleting assignment");
@@ -304,7 +294,8 @@ impl<'tcx> Action<'tcx> {
 
                 // Replace all uses of the destination local with the constant.
                 let mut visitor = ConstantPropagationVisitor::new(dest_local,
-                                                                  src_constant);
+                                                                  src_constant,
+                                                                  tcx);
                 for dest_place_use in &dest_local_info.defs_and_uses {
                     visitor.visit_location(body, dest_place_use.location)
                 }
@@ -336,33 +327,42 @@ impl<'tcx> Action<'tcx> {
 struct ConstantPropagationVisitor<'tcx> {
     dest_local: Local,
     constant: Constant<'tcx>,
+    tcx: TyCtxt<'tcx>,
     uses_replaced: usize,
 }
 
 impl<'tcx> ConstantPropagationVisitor<'tcx> {
-    fn new(dest_local: Local, constant: Constant<'tcx>)
+    fn new(dest_local: Local, constant: Constant<'tcx>, tcx: TyCtxt<'tcx>)
            -> ConstantPropagationVisitor<'tcx> {
         ConstantPropagationVisitor {
             dest_local,
             constant,
+            tcx,
             uses_replaced: 0,
         }
     }
 }
 
 impl<'tcx> MutVisitor<'tcx> for ConstantPropagationVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_operand(&mut self, operand: &mut Operand<'tcx>, location: Location) {
         self.super_operand(operand, location);
 
-        match *operand {
-            Operand::Copy(Place {
-                base: PlaceBase::Local(local),
-                projection: box [],
-            }) |
-            Operand::Move(Place {
-                base: PlaceBase::Local(local),
-                projection: box [],
-            }) if local == self.dest_local => {}
+        match operand {
+            Operand::Copy(place) |
+            Operand::Move(place) => {
+                if let Some(local) = place.as_local() {
+                    if local == self.dest_local {
+                    } else {
+                        return;
+                    }
+                } else {
+                    return;
+                }
+            }
             _ => return,
         }
 

src/librustc_mir/transform/deaggregator.rs

@@ -45,6 +45,7 @@ impl<'tcx> MirPass<'tcx> for Deaggregator {
                     }),
                     *kind,
                     source_info,
+                    tcx,
                 ))
             });
         }

src/librustc_mir/transform/erase_regions.rs

@@ -23,6 +23,10 @@ impl EraseRegionsVisitor<'tcx> {
 }
 
 impl MutVisitor<'tcx> for EraseRegionsVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_ty(&mut self, ty: &mut Ty<'tcx>, _: TyContext) {
         *ty = self.tcx.erase_regions(ty);
     }

src/librustc_mir/transform/generator.rs

@@ -74,12 +74,17 @@ use crate::util::liveness;
 
 pub struct StateTransform;
 
-struct RenameLocalVisitor {
+struct RenameLocalVisitor<'tcx> {
     from: Local,
     to: Local,
+    tcx: TyCtxt<'tcx>,
 }
 
-impl<'tcx> MutVisitor<'tcx> for RenameLocalVisitor {
+impl<'tcx> MutVisitor<'tcx> for RenameLocalVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_local(&mut self,
                    local: &mut Local,
                    _: PlaceContext,
@@ -102,9 +107,15 @@ impl<'tcx> MutVisitor<'tcx> for RenameLocalVisitor {
     }
 }
 
-struct DerefArgVisitor;
+struct DerefArgVisitor<'tcx> {
+    tcx: TyCtxt<'tcx>,
+}
+
+impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
 
-impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor {
     fn visit_local(&mut self,
                    local: &mut Local,
                    _: PlaceContext,
@@ -119,8 +130,8 @@ impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor {
         if place.base == PlaceBase::Local(self_arg()) {
             replace_base(place, Place {
                 base: PlaceBase::Local(self_arg()),
-                projection: Box::new([ProjectionElem::Deref]),
-            });
+                projection: self.tcx().intern_place_elems(&vec![ProjectionElem::Deref]),
+            }, self.tcx);
         } else {
             self.visit_place_base(&mut place.base, context, location);
 
@@ -135,9 +146,14 @@ impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor {
 
 struct PinArgVisitor<'tcx> {
     ref_gen_ty: Ty<'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
 impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_local(&mut self,
                    local: &mut Local,
                    _: PlaceContext,
@@ -145,15 +161,19 @@ impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {
         assert_ne!(*local, self_arg());
     }
 
-    fn visit_place(&mut self,
-                    place: &mut Place<'tcx>,
-                    context: PlaceContext,
-                    location: Location) {
+    fn visit_place(&mut self, place: &mut Place<'tcx>, context: PlaceContext, location: Location) {
         if place.base == PlaceBase::Local(self_arg()) {
-            replace_base(place, Place {
+            replace_base(
+                place,
+                Place {
                     base: PlaceBase::Local(self_arg()),
-                projection: Box::new([ProjectionElem::Field(Field::new(0), self.ref_gen_ty)]),
-            });
+                    projection: self.tcx().intern_place_elems(&vec![ProjectionElem::Field(
+                            Field::new(0),
+                            self.ref_gen_ty,
+                    )]),
+                },
+                self.tcx,
+            );
         } else {
             self.visit_place_base(&mut place.base, context, location);
 
@@ -166,13 +186,13 @@ impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {
     }
 }
 
-fn replace_base(place: &mut Place<'tcx>, new_base: Place<'tcx>) {
+fn replace_base<'tcx>(place: &mut Place<'tcx>, new_base: Place<'tcx>, tcx: TyCtxt<'tcx>) {
     place.base = new_base.base;
 
     let mut new_projection = new_base.projection.to_vec();
     new_projection.append(&mut place.projection.to_vec());
 
-    place.projection = new_projection.into_boxed_slice();
+    place.projection = tcx.intern_place_elems(&new_projection);
 }
 
 fn self_arg() -> Local {
@@ -226,13 +246,13 @@ impl TransformVisitor<'tcx> {
     // Create a Place referencing a generator struct field
     fn make_field(&self, variant_index: VariantIdx, idx: usize, ty: Ty<'tcx>) -> Place<'tcx> {
         let self_place = Place::from(self_arg());
-        let base = self_place.downcast_unnamed(variant_index);
+        let base = self.tcx.mk_place_downcast_unnamed(self_place, variant_index);
         let mut projection = base.projection.to_vec();
         projection.push(ProjectionElem::Field(Field::new(idx), ty));
 
         Place {
             base: base.base,
-            projection: projection.into_boxed_slice(),
+            projection: self.tcx.intern_place_elems(&projection),
         }
     }
 
@@ -264,6 +284,10 @@ impl TransformVisitor<'tcx> {
 }
 
 impl MutVisitor<'tcx> for TransformVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_local(&mut self,
                    local: &mut Local,
                    _: PlaceContext,
@@ -280,7 +304,7 @@ impl MutVisitor<'tcx> for TransformVisitor<'tcx> {
         if let PlaceBase::Local(l) = place.base {
             // Replace an Local in the remap with a generator struct access
             if let Some(&(ty, variant_index, idx)) = self.remap.get(&l) {
-                replace_base(place, self.make_field(variant_index, idx, ty));
+                replace_base(place, self.make_field(variant_index, idx, ty), self.tcx);
             }
         } else {
             self.visit_place_base(&mut place.base, context, location);
@@ -375,7 +399,7 @@ fn make_generator_state_argument_indirect<'tcx>(
     body.local_decls.raw[1].ty = ref_gen_ty;
 
     // Add a deref to accesses of the generator state
-    DerefArgVisitor.visit_body(body);
+    DerefArgVisitor { tcx }.visit_body(body);
 }
 
 fn make_generator_state_argument_pinned<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
@@ -390,12 +414,13 @@ fn make_generator_state_argument_pinned<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body
     body.local_decls.raw[1].ty = pin_ref_gen_ty;
 
     // Add the Pin field access to accesses of the generator state
-    PinArgVisitor { ref_gen_ty }.visit_body(body);
+    PinArgVisitor { ref_gen_ty, tcx }.visit_body(body);
 }
 
 fn replace_result_variable<'tcx>(
     ret_ty: Ty<'tcx>,
     body: &mut Body<'tcx>,
+    tcx: TyCtxt<'tcx>,
 ) -> Local {
     let source_info = source_info(body);
     let new_ret = LocalDecl {
@@ -416,6 +441,7 @@ fn replace_result_variable<'tcx>(
     RenameLocalVisitor {
         from: RETURN_PLACE,
         to: new_ret_local,
+        tcx,
     }.visit_body(body);
 
     new_ret_local
@@ -864,17 +890,24 @@ fn elaborate_generator_drops<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, body: &mut
 
     for (block, block_data) in body.basic_blocks().iter_enumerated() {
         let (target, unwind, source_info) = match block_data.terminator() {
-            &Terminator {
+            Terminator {
                 source_info,
                 kind: TerminatorKind::Drop {
-                    location: Place {
-                        base: PlaceBase::Local(local),
-                        projection: box [],
-                    },
+                    location,
                     target,
                     unwind
                 }
-            } if local == gen => (target, unwind, source_info),
+            } => {
+                if let Some(local) = location.as_local() {
+                    if local == gen {
+                        (target, unwind, source_info)
+                    } else {
+                        continue;
+                    }
+                } else {
+                    continue;
+                }
+            }
             _ => continue,
         };
         let unwind = if block_data.is_cleanup {
@@ -884,10 +917,10 @@ fn elaborate_generator_drops<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, body: &mut
         };
         elaborate_drop(
             &mut elaborator,
-            source_info,
+            *source_info,
             &Place::from(gen),
             (),
-            target,
+            *target,
             unwind,
             block,
         );
@@ -1175,7 +1208,7 @@ impl<'tcx> MirPass<'tcx> for StateTransform {
 
         // We rename RETURN_PLACE which has type mir.return_ty to new_ret_local
         // RETURN_PLACE then is a fresh unused local with type ret_ty.
-        let new_ret_local = replace_result_variable(ret_ty, body);
+        let new_ret_local = replace_result_variable(ret_ty, body, tcx);
 
         // Extract locals which are live across suspension point into `layout`
         // `remap` gives a mapping from local indices onto generator struct indices

src/librustc_mir/transform/inline.rs

@@ -461,7 +461,7 @@ impl Inliner<'tcx> {
                     };
                     caller_body[callsite.bb]
                         .statements.push(stmt);
-                    tmp.deref()
+                    self.tcx.mk_place_deref(tmp)
                 } else {
                     destination.0
                 };
@@ -481,6 +481,7 @@ impl Inliner<'tcx> {
                     return_block,
                     cleanup_block: cleanup,
                     in_cleanup_block: false,
+                    tcx: self.tcx,
                 };
 
 
@@ -559,7 +560,8 @@ impl Inliner<'tcx> {
             let tuple_tmp_args =
                 tuple_tys.iter().enumerate().map(|(i, ty)| {
                     // This is e.g., `tuple_tmp.0` in our example above.
-                    let tuple_field = Operand::Move(tuple.clone().field(
+                    let tuple_field = Operand::Move(tcx.mk_place_field(
+                        tuple.clone(),
                         Field::new(i),
                         ty.expect_ty(),
                     ));
@@ -587,15 +589,14 @@ impl Inliner<'tcx> {
         // FIXME: Analysis of the usage of the arguments to avoid
         // unnecessary temporaries.
 
-        if let Operand::Move(Place {
-            base: PlaceBase::Local(local),
-            projection: box [],
-        }) = arg {
+        if let Operand::Move(place) = &arg {
+            if let Some(local) = place.as_local() {
                 if caller_body.local_kind(local) == LocalKind::Temp {
                     // Reuse the operand if it's a temporary already
                     return local;
                 }
             }
+        }
 
         debug!("creating temp for argument {:?}", arg);
         // Otherwise, create a temporary for the arg
@@ -639,6 +640,7 @@ struct Integrator<'a, 'tcx> {
     return_block: BasicBlock,
     cleanup_block: Option<BasicBlock>,
     in_cleanup_block: bool,
+    tcx: TyCtxt<'tcx>,
 }
 
 impl<'a, 'tcx> Integrator<'a, 'tcx> {
@@ -650,14 +652,9 @@ impl<'a, 'tcx> Integrator<'a, 'tcx> {
 
     fn make_integrate_local(&self, local: &Local) -> Local {
         if *local == RETURN_PLACE {
-            match self.destination {
-                Place {
-                    base: PlaceBase::Local(l),
-                    projection: box [],
-                } => {
-                    return l;
-                },
-                ref place => bug!("Return place is {:?}, not local", place)
+            match self.destination.as_local() {
+                Some(l) => return l,
+                ref place => bug!("Return place is {:?}, not local", place),
             }
         }
 
@@ -671,6 +668,10 @@ impl<'a, 'tcx> Integrator<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_local(
         &mut self,
         local: &mut Local,
@@ -686,19 +687,13 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
         context: PlaceContext,
         location: Location,
     ) {
-        match place {
-            Place {
-                base: PlaceBase::Local(RETURN_PLACE),
-                projection: box [],
-            } => {
+        if let Some(RETURN_PLACE) = place.as_local() {
             // Return pointer; update the place itself
             *place = self.destination.clone();
-            },
-            _ => {
+        } else {
             self.super_place(place, context, location);
         }
     }
-    }
 
     fn process_projection_elem(
         &mut self,

src/librustc_mir/transform/instcombine.rs

@@ -1,7 +1,8 @@
 //! Performs various peephole optimizations.
 
-use rustc::mir::{Constant, Location, Place, PlaceBase, Body, Operand, ProjectionElem, Rvalue,
-    Local};
+use rustc::mir::{
+    Constant, Location, Place, PlaceBase, PlaceRef, Body, Operand, ProjectionElem, Rvalue, Local
+};
 use rustc::mir::visit::{MutVisitor, Visitor};
 use rustc::ty::{self, TyCtxt};
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
@@ -28,32 +29,33 @@ impl<'tcx> MirPass<'tcx> for InstCombine {
         };
 
         // Then carry out those optimizations.
-        MutVisitor::visit_body(&mut InstCombineVisitor { optimizations }, body);
+        MutVisitor::visit_body(&mut InstCombineVisitor { optimizations, tcx }, body);
     }
 }
 
 pub struct InstCombineVisitor<'tcx> {
     optimizations: OptimizationList<'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
 impl<'tcx> MutVisitor<'tcx> for InstCombineVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_rvalue(&mut self, rvalue: &mut Rvalue<'tcx>, location: Location) {
         if self.optimizations.and_stars.remove(&location) {
             debug!("replacing `&*`: {:?}", rvalue);
-            let new_place = match *rvalue {
-                Rvalue::Ref(_, _, Place {
-                    ref mut base,
-                    projection: ref mut projection @ box [.., _],
-                }) => {
-                    if let box [proj_l @ .., proj_r] = projection {
-                        let place = Place {
-                            // Replace with dummy
-                            base: mem::replace(base, PlaceBase::Local(Local::new(0))),
-                            projection: proj_l.to_vec().into_boxed_slice(),
-                        };
-                        *projection = vec![proj_r.clone()].into_boxed_slice();
+            let new_place = match rvalue {
+                Rvalue::Ref(_, _, place) => {
+                    if let &[ref proj_l @ .., proj_r] = place.projection.as_ref() {
+                        place.projection = self.tcx().intern_place_elems(&vec![proj_r.clone()]);
 
-                        place
+                        Place {
+                            // Replace with dummy
+                            base: mem::replace(&mut place.base, PlaceBase::Local(Local::new(0))),
+                            projection: self.tcx().intern_place_elems(proj_l),
+                        }
                     } else {
                         unreachable!();
                     }
@@ -91,14 +93,16 @@ impl OptimizationFinder<'b, 'tcx> {
 
 impl Visitor<'tcx> for OptimizationFinder<'b, 'tcx> {
     fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
-        if let Rvalue::Ref(_, _, Place {
+        if let Rvalue::Ref(_, _, place) = rvalue {
+            if let PlaceRef {
                 base,
-            projection: box [proj_base @ .., ProjectionElem::Deref],
-        }) = rvalue {
+                projection: &[ref proj_base @ .., ProjectionElem::Deref],
+            } = place.as_ref() {
                 if Place::ty_from(base, proj_base, self.body, self.tcx).ty.is_region_ptr() {
                     self.optimizations.and_stars.insert(location);
                 }
             }
+        }
 
         if let Rvalue::Len(ref place) = *rvalue {
             let place_ty = place.ty(&self.body.local_decls, self.tcx).ty;

src/librustc_mir/transform/mod.rs

@@ -228,7 +228,7 @@ fn run_optimization_passes<'tcx>(
 ) {
     run_passes(tcx, body, InstanceDef::Item(def_id), promoted, MirPhase::Optimized, &[
         // Remove all things only needed by analysis
-        &no_landing_pads::NoLandingPads,
+        &no_landing_pads::NoLandingPads::new(tcx),
         &simplify_branches::SimplifyBranches::new("initial"),
         &remove_noop_landing_pads::RemoveNoopLandingPads,
         &cleanup_post_borrowck::CleanupNonCodegenStatements,
@@ -238,7 +238,7 @@ fn run_optimization_passes<'tcx>(
         // These next passes must be executed together
         &add_call_guards::CriticalCallEdges,
         &elaborate_drops::ElaborateDrops,
-        &no_landing_pads::NoLandingPads,
+        &no_landing_pads::NoLandingPads::new(tcx),
         // AddMovesForPackedDrops needs to run after drop
         // elaboration.
         &add_moves_for_packed_drops::AddMovesForPackedDrops,
@@ -257,7 +257,7 @@ fn run_optimization_passes<'tcx>(
 
 
         // Optimizations begin.
-        &uniform_array_move_out::RestoreSubsliceArrayMoveOut,
+        &uniform_array_move_out::RestoreSubsliceArrayMoveOut::new(tcx),
         &inline::Inline,
 
         // Lowering generator control-flow and variables

src/librustc_mir/transform/no_landing_pads.rs

@@ -6,9 +6,17 @@ use rustc::mir::*;
 use rustc::mir::visit::MutVisitor;
 use crate::transform::{MirPass, MirSource};
 
-pub struct NoLandingPads;
+pub struct NoLandingPads<'tcx> {
+    tcx: TyCtxt<'tcx>,
+}
 
-impl<'tcx> MirPass<'tcx> for NoLandingPads {
+impl<'tcx> NoLandingPads<'tcx> {
+    pub fn new(tcx: TyCtxt<'tcx>) -> Self {
+        NoLandingPads { tcx }
+    }
+}
+
+impl<'tcx> MirPass<'tcx> for NoLandingPads<'tcx> {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, _: MirSource<'tcx>, body: &mut Body<'tcx>) {
         no_landing_pads(tcx, body)
     }
@@ -16,11 +24,15 @@ impl<'tcx> MirPass<'tcx> for NoLandingPads {
 
 pub fn no_landing_pads<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     if tcx.sess.no_landing_pads() {
-        NoLandingPads.visit_body(body);
+        NoLandingPads::new(tcx).visit_body(body);
     }
 }
 
-impl<'tcx> MutVisitor<'tcx> for NoLandingPads {
+impl<'tcx> MutVisitor<'tcx> for NoLandingPads<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_terminator_kind(&mut self,
                         kind: &mut TerminatorKind<'tcx>,
                         location: Location) {

src/librustc_mir/transform/promote_consts.rs

@@ -17,7 +17,7 @@ use rustc::mir::*;
 use rustc::mir::visit::{PlaceContext, MutatingUseContext, MutVisitor, Visitor};
 use rustc::mir::traversal::ReversePostorder;
 use rustc::ty::subst::InternalSubsts;
-use rustc::ty::TyCtxt;
+use rustc::ty::{List, TyCtxt};
 use syntax_pos::Span;
 
 use rustc_index::vec::{IndexVec, Idx};
@@ -321,7 +321,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                         ty,
                         def_id,
                     }),
-                    projection: box [],
+                    projection: List::empty(),
                 }
             };
             let (blocks, local_decls) = self.source.basic_blocks_and_local_decls_mut();
@@ -339,7 +339,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                                     &mut place.base,
                                     promoted_place(ty, span).base,
                                 ),
-                                projection: box [],
+                                projection: List::empty(),
                             })
                         }
                         _ => bug!()
@@ -396,6 +396,10 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
 
 /// Replaces all temporaries with their promoted counterparts.
 impl<'a, 'tcx> MutVisitor<'tcx> for Promoter<'a, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_local(&mut self,
                    local: &mut Local,
                    _: PlaceContext,
@@ -434,16 +438,15 @@ pub fn promote_candidates<'tcx>(
         match candidate {
             Candidate::Repeat(Location { block, statement_index }) |
             Candidate::Ref(Location { block, statement_index }) => {
-                match body[block].statements[statement_index].kind {
-                    StatementKind::Assign(box(Place {
-                        base: PlaceBase::Local(local),
-                        projection: box [],
-                    }, _)) => {
+                match &body[block].statements[statement_index].kind {
+                    StatementKind::Assign(box(place, _)) => {
+                        if let Some(local) = place.as_local() {
                             if temps[local] == TempState::PromotedOut {
                                 // Already promoted.
                                 continue;
                             }
                         }
+                    }
                     _ => {}
                 }
             }
@@ -487,30 +490,32 @@ pub fn promote_candidates<'tcx>(
     let promoted = |index: Local| temps[index] == TempState::PromotedOut;
     for block in body.basic_blocks_mut() {
         block.statements.retain(|statement| {
-            match statement.kind {
-                StatementKind::Assign(box(Place {
-                    base: PlaceBase::Local(index),
-                    projection: box [],
-                }, _)) |
+            match &statement.kind {
+                StatementKind::Assign(box(place, _)) => {
+                    if let Some(index) = place.as_local() {
+                        !promoted(index)
+                    } else {
+                        true
+                    }
+                }
                 StatementKind::StorageLive(index) |
                 StatementKind::StorageDead(index) => {
-                    !promoted(index)
+                    !promoted(*index)
                 }
                 _ => true
             }
         });
         let terminator = block.terminator_mut();
-        match terminator.kind {
-            TerminatorKind::Drop { location: Place {
-                base: PlaceBase::Local(index),
-                projection: box [],
-            }, target, .. } => {
+        match &terminator.kind {
+            TerminatorKind::Drop { location: place, target, .. } => {
+                if let Some(index) = place.as_local() {
                     if promoted(index) {
                         terminator.kind = TerminatorKind::Goto {
-                        target,
+                            target: *target,
                         };
                     }
                 }
+            }
             _ => {}
         }
     }

src/librustc_mir/transform/qualify_consts.rs

@@ -292,8 +292,8 @@ trait Qualif {
 
             Rvalue::Ref(_, _, ref place) => {
                 // Special-case reborrows to be more like a copy of the reference.
-                if let box [proj_base @ .., elem] = &place.projection {
-                    if ProjectionElem::Deref == *elem {
+                if let &[ref proj_base @ .., elem] = place.projection.as_ref() {
+                    if ProjectionElem::Deref == elem {
                         let base_ty = Place::ty_from(&place.base, proj_base, cx.body, cx.tcx).ty;
                         if let ty::Ref(..) = base_ty.kind {
                             return Self::in_place(cx, PlaceRef {
@@ -1041,28 +1041,26 @@ impl<'a, 'tcx> Checker<'a, 'tcx> {
             match *candidate {
                 Candidate::Repeat(Location { block: bb, statement_index: stmt_idx }) => {
                     if let StatementKind::Assign(box(_, Rvalue::Repeat(
-                        Operand::Move(Place {
-                            base: PlaceBase::Local(index),
-                            projection: box [],
-                        }),
+                        Operand::Move(place),
                         _
-                    ))) = self.body[bb].statements[stmt_idx].kind {
+                    ))) = &self.body[bb].statements[stmt_idx].kind {
+                        if let Some(index) = place.as_local() {
                             promoted_temps.insert(index);
                         }
                     }
+                }
                 Candidate::Ref(Location { block: bb, statement_index: stmt_idx }) => {
                     if let StatementKind::Assign(
                         box(
                             _,
-                            Rvalue::Ref(_, _, Place {
-                                base: PlaceBase::Local(index),
-                                projection: box [],
-                            })
+                            Rvalue::Ref(_, _, place)
                         )
-                    ) = self.body[bb].statements[stmt_idx].kind {
+                    ) = &self.body[bb].statements[stmt_idx].kind {
+                        if let Some(index) = place.as_local() {
                             promoted_temps.insert(index);
                         }
                     }
+                }
                 Candidate::Argument { .. } => {}
             }
         }
@@ -1237,10 +1235,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
         match *operand {
             Operand::Move(ref place) => {
                 // Mark the consumed locals to indicate later drops are noops.
-                if let Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                } = *place {
+                if let Some(local) = place.as_local() {
                     self.cx.per_local[NeedsDrop].remove(local);
                 }
             }
@@ -1256,8 +1251,8 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
         if let Rvalue::Ref(_, kind, ref place) = *rvalue {
             // Special-case reborrows.
             let mut reborrow_place = None;
-            if let box [proj_base @ .., elem] = &place.projection {
-                if *elem == ProjectionElem::Deref {
+            if let &[ref proj_base @ .., elem] = place.projection.as_ref() {
+                if elem == ProjectionElem::Deref {
                     let base_ty = Place::ty_from(&place.base, proj_base, self.body, self.tcx).ty;
                     if let ty::Ref(..) = base_ty.kind {
                         reborrow_place = Some(proj_base);
@@ -1568,10 +1563,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
                 unleash_miri!(self);
                 // HACK(eddyb): emulate a bit of dataflow analysis,
                 // conservatively, that drop elaboration will do.
-                let needs_drop = if let Place {
-                    base: PlaceBase::Local(local),
-                    projection: box [],
-                } = *place {
+                let needs_drop = if let Some(local) = place.as_local() {
                     if NeedsDrop::in_local(self, local) {
                         Some(self.body.local_decls[local].source_info.span)
                     } else {
@@ -1817,16 +1809,17 @@ fn remove_drop_and_storage_dead_on_promoted_locals(
             }
         });
         let terminator = block.terminator_mut();
-        match terminator.kind {
+        match &terminator.kind {
             TerminatorKind::Drop {
-                location: Place {
-                    base: PlaceBase::Local(index),
-                    projection: box [],
-                },
+                location,
                 target,
                 ..
-            } if promoted_temps.contains(index) => {
-                terminator.kind = TerminatorKind::Goto { target };
+            } => {
+                if let Some(index) = location.as_local() {
+                    if promoted_temps.contains(index) {
+                        terminator.kind = TerminatorKind::Goto { target: *target };
+                    }
+                }
             }
             _ => {}
         }

src/librustc_mir/transform/qualify_min_const_fn.rs

@@ -259,8 +259,8 @@ fn check_place(
     def_id: DefId,
     body: &Body<'tcx>
 ) -> McfResult {
-    let mut cursor = &*place.projection;
-    while let [proj_base @ .., elem] = cursor {
+    let mut cursor = place.projection.as_ref();
+    while let &[ref proj_base @ .., elem] = cursor {
         cursor = proj_base;
         match elem {
             ProjectionElem::Downcast(..) => {

src/librustc_mir/transform/remove_noop_landing_pads.rs

@@ -32,7 +32,7 @@ impl RemoveNoopLandingPads {
         nop_landing_pads: &BitSet<BasicBlock>,
     ) -> bool {
         for stmt in &body[bb].statements {
-            match stmt.kind {
+            match &stmt.kind {
                 StatementKind::FakeRead(..) |
                 StatementKind::StorageLive(_) |
                 StatementKind::StorageDead(_) |
@@ -41,12 +41,13 @@ impl RemoveNoopLandingPads {
                     // These are all nops in a landing pad
                 }
 
-                StatementKind::Assign(box(Place {
-                    base: PlaceBase::Local(_),
-                    projection: box [],
-                }, Rvalue::Use(_))) => {
+                StatementKind::Assign(box(place, Rvalue::Use(_))) => {
+                    if place.as_local().is_some() {
                         // Writing to a local (e.g., a drop flag) does not
                         // turn a landing pad to a non-nop
+                    } else {
+                        return false;
+                    }
                 }
 
                 StatementKind::Assign { .. } |

src/librustc_mir/transform/rustc_peek.rs

@@ -155,8 +155,8 @@ fn value_assigned_to_local<'a, 'tcx>(
     local: Local,
 ) -> Option<&'a mir::Rvalue<'tcx>> {
     if let mir::StatementKind::Assign(box (place, rvalue)) = &stmt.kind {
-        if let mir::Place { base: mir::PlaceBase::Local(l), projection: box [] } = place {
-            if local == *l {
+        if let Some(l) = place.as_local() {
+            if local == l {
                 return Some(&*rvalue);
             }
         }
@@ -192,7 +192,7 @@ impl PeekCall {
         tcx: TyCtxt<'tcx>,
         terminator: &mir::Terminator<'tcx>,
     ) -> Option<Self> {
-        use mir::{Operand, Place, PlaceBase};
+        use mir::Operand;
 
         let span = terminator.source_info.span;
         if let mir::TerminatorKind::Call { func: Operand::Constant(func), args, .. } =
@@ -207,14 +207,23 @@ impl PeekCall {
 
                 assert_eq!(args.len(), 1);
                 let kind = PeekCallKind::from_arg_ty(substs.type_at(0));
-                let arg = match args[0] {
-                    | Operand::Copy(Place { base: PlaceBase::Local(local), projection: box [] })
-                    | Operand::Move(Place { base: PlaceBase::Local(local), projection: box [] })
-                    => local,
-
+                let arg = match &args[0] {
+                    Operand::Copy(place) | Operand::Move(place) => {
+                        if let Some(local) = place.as_local() {
+                            local
+                        } else {
+                            tcx.sess.diagnostic().span_err(
+                                span,
+                                "dataflow::sanity_check cannot feed a non-temp to rustc_peek.",
+                            );
+                            return None;
+                        }
+                    }
                     _ => {
                         tcx.sess.diagnostic().span_err(
-                            span, "dataflow::sanity_check cannot feed a non-temp to rustc_peek.");
+                            span,
+                            "dataflow::sanity_check cannot feed a non-temp to rustc_peek.",
+                        );
                         return None;
                     }
                 };
@@ -277,12 +286,11 @@ impl<'tcx> RustcPeekAt<'tcx> for IndirectlyMutableLocals<'_, 'tcx> {
         call: PeekCall,
     ) {
         warn!("peek_at: place={:?}", place);
-        let local = match place {
-            mir::Place { base: mir::PlaceBase::Local(l), projection: box [] } => *l,
-            _ => {
+        let local = if let Some(l) = place.as_local() {
+            l
+        } else {
             tcx.sess.span_err(call.span, "rustc_peek: argument was not a local");
             return;
-            }
         };
 
         if !flow_state.contains(local) {

src/librustc_mir/transform/simplify.rs

@@ -319,7 +319,7 @@ impl<'tcx> MirPass<'tcx> for SimplifyLocals {
 
         let map = make_local_map(&mut body.local_decls, locals);
         // Update references to all vars and tmps now
-        LocalUpdater { map }.visit_body(body);
+        LocalUpdater { map, tcx }.visit_body(body);
         body.local_decls.shrink_to_fit();
     }
 }
@@ -374,11 +374,16 @@ impl<'a, 'tcx> Visitor<'tcx> for DeclMarker<'a, 'tcx> {
     }
 }
 
-struct LocalUpdater {
+struct LocalUpdater<'tcx> {
     map: IndexVec<Local, Option<Local>>,
+    tcx: TyCtxt<'tcx>,
 }
 
-impl<'tcx> MutVisitor<'tcx> for LocalUpdater {
+impl<'tcx> MutVisitor<'tcx> for LocalUpdater<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_basic_block_data(&mut self, block: BasicBlock, data: &mut BasicBlockData<'tcx>) {
         // Remove unnecessary StorageLive and StorageDead annotations.
         data.statements.retain(|stmt| {

src/librustc_mir/transform/uniform_array_move_out.rs

@@ -61,7 +61,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UniformArrayMoveOutVisitor<'a, 'tcx> {
                     rvalue: &Rvalue<'tcx>,
                     location: Location) {
         if let Rvalue::Use(Operand::Move(ref src_place)) = rvalue {
-            if let box [proj_base @ .., elem] = &src_place.projection {
+            if let &[ref proj_base @ .., elem] = src_place.projection.as_ref() {
                 if let ProjectionElem::ConstantIndex{offset: _,
                                                      min_length: _,
                                                      from_end: false} = elem {
@@ -116,16 +116,13 @@ impl<'a, 'tcx> UniformArrayMoveOutVisitor<'a, 'tcx> {
                             min_length: size,
                             from_end: false,
                         });
-                        self.patch.add_assign(location,
+                        self.patch.add_assign(
+                            location,
                             Place::from(temp),
-                                              Rvalue::Use(
-                                                  Operand::Move(
-                                                      Place {
+                            Rvalue::Use(Operand::Move(Place {
                                 base: base.clone(),
-                                                          projection: projection.into_boxed_slice(),
-                                                      }
-                                                  )
-                                              )
+                                projection: self.tcx.intern_place_elems(&projection),
+                            })),
                         );
                         temp
                     }).collect();
@@ -153,16 +150,13 @@ impl<'a, 'tcx> UniformArrayMoveOutVisitor<'a, 'tcx> {
                         min_length: size,
                         from_end: false,
                     });
-                    self.patch.add_assign(location,
+                    self.patch.add_assign(
+                        location,
                         dst_place.clone(),
-                                          Rvalue::Use(
-                                              Operand::Move(
-                                                  Place {
+                        Rvalue::Use(Operand::Move(Place {
                             base: base.clone(),
-                                                      projection: projection.into_boxed_slice(),
-                                                  }
-                                              )
-                                          )
+                            projection: self.tcx.intern_place_elems(&projection),
+                        })),
                     );
                 }
                 _ => {}
@@ -185,9 +179,11 @@ impl<'a, 'tcx> UniformArrayMoveOutVisitor<'a, 'tcx> {
 //
 // replaced by _10 = move _2[:-1];
 
-pub struct RestoreSubsliceArrayMoveOut;
+pub struct RestoreSubsliceArrayMoveOut<'tcx> {
+    tcx: TyCtxt<'tcx>
+}
 
-impl<'tcx> MirPass<'tcx> for RestoreSubsliceArrayMoveOut {
+impl<'tcx> MirPass<'tcx> for RestoreSubsliceArrayMoveOut<'tcx> {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, src: MirSource<'tcx>, body: &mut Body<'tcx>) {
         let mut patch = MirPatch::new(body);
         let param_env = tcx.param_env(src.def_id());
@@ -203,11 +199,9 @@ impl<'tcx> MirPass<'tcx> for RestoreSubsliceArrayMoveOut {
                 if let StatementKind::Assign(box(ref dst_place, ref rval)) = statement.kind {
                     if let Rvalue::Aggregate(box AggregateKind::Array(_), ref items) = *rval {
                         let items : Vec<_> = items.iter().map(|item| {
-                            if let Operand::Move(Place {
-                                base: PlaceBase::Local(local),
-                                projection: box [],
-                            }) = item {
-                                let local_use = &visitor.locals_use[*local];
+                            if let Operand::Move(place) = item {
+                                if let Some(local) = place.as_local() {
+                                    let local_use = &visitor.locals_use[local];
                                     let opt_index_and_place =
                                         Self::try_get_item_source(local_use, body);
                                     // each local should be used twice:
@@ -217,6 +211,7 @@ impl<'tcx> MirPass<'tcx> for RestoreSubsliceArrayMoveOut {
                                         return Some((local_use, index, src_place));
                                     }
                                 }
+                            }
                             None
                         }).collect();
 
@@ -230,7 +225,9 @@ impl<'tcx> MirPass<'tcx> for RestoreSubsliceArrayMoveOut {
                                 None
                             }
                         });
-                        Self::check_and_patch(*candidate, &items, opt_size, &mut patch, dst_place);
+                        let restore_subslice = RestoreSubsliceArrayMoveOut { tcx };
+                        restore_subslice
+                            .check_and_patch(*candidate, &items, opt_size, &mut patch, dst_place);
                     }
                 }
             }
@@ -239,11 +236,16 @@ impl<'tcx> MirPass<'tcx> for RestoreSubsliceArrayMoveOut {
     }
 }
 
-impl RestoreSubsliceArrayMoveOut {
+impl RestoreSubsliceArrayMoveOut<'tcx> {
+    pub fn new(tcx: TyCtxt<'tcx>) -> Self {
+        RestoreSubsliceArrayMoveOut { tcx }
+    }
+
     // Checks that source has size, all locals are inited from same source place and
     // indices is an integer interval. If all checks pass do the replacent.
     // items are Vec<Option<LocalUse, index in source array, source place for init local>>
-    fn check_and_patch<'tcx>(candidate: Location,
+    fn check_and_patch(&self,
+                       candidate: Location,
                        items: &[Option<(&LocalUse, u32, PlaceRef<'_, 'tcx>)>],
                        opt_size: Option<u64>,
                        patch: &mut MirPatch<'tcx>,
@@ -280,43 +282,35 @@ impl RestoreSubsliceArrayMoveOut {
                 dst_place.clone(),
                 Rvalue::Use(Operand::Move(Place {
                     base: src_place.base.clone(),
-                    projection: projection.into_boxed_slice(),
+                    projection: self.tcx.intern_place_elems(&projection),
                 })),
             );
         }
     }
 
-    fn try_get_item_source<'a, 'tcx>(local_use: &LocalUse,
+    fn try_get_item_source<'a>(local_use: &LocalUse,
                                body: &'a Body<'tcx>) -> Option<(u32, PlaceRef<'a, 'tcx>)> {
         if let Some(location) = local_use.first_use {
             let block = &body[location.block];
             if block.statements.len() > location.statement_index {
                 let statement = &block.statements[location.statement_index];
                 if let StatementKind::Assign(
-                    box(
-                        Place {
-                            base: PlaceBase::Local(_),
-                            projection: box [],
-                        },
-                        Rvalue::Use(Operand::Move(Place {
+                    box(place, Rvalue::Use(Operand::Move(src_place)))
+                ) = &statement.kind {
+                    if let (Some(_), PlaceRef {
                         base: _,
-                            projection: box [.., ProjectionElem::ConstantIndex {
+                        projection: &[.., ProjectionElem::ConstantIndex {
                             offset, min_length: _, from_end: false
                         }],
-                        })),
-                    )
-                ) = &statement.kind {
-                    // FIXME remove once we can use slices patterns
+                    }) = (place.as_local(), src_place.as_ref()) {
                         if let StatementKind::Assign(
-                        box(
-                            _,
-                            Rvalue::Use(Operand::Move(Place {
-                                base,
-                                projection: box [proj_base @ .., _],
-                            })),
-                        )
+                            box(_, Rvalue::Use(Operand::Move(place)))
                         ) = &statement.kind {
-                        return Some((*offset, PlaceRef {
+                            if let PlaceRef {
+                                base,
+                                projection: &[ref proj_base @ .., _],
+                            } = place.as_ref() {
+                                return Some((offset, PlaceRef {
                                     base,
                                     projection: proj_base,
                                 }))
@@ -324,6 +318,8 @@ impl RestoreSubsliceArrayMoveOut {
                         }
                     }
                 }
+            }
+        }
         None
     }
 }

src/librustc_mir/util/aggregate.rs

@@ -1,5 +1,5 @@
 use rustc::mir::*;
-use rustc::ty::Ty;
+use rustc::ty::{Ty, TyCtxt};
 use rustc::ty::layout::VariantIdx;
 use rustc_index::vec::Idx;
 
@@ -17,6 +17,7 @@ pub fn expand_aggregate<'tcx>(
     operands: impl Iterator<Item=(Operand<'tcx>, Ty<'tcx>)> + TrustedLen,
     kind: AggregateKind<'tcx>,
     source_info: SourceInfo,
+    tcx: TyCtxt<'tcx>,
 ) -> impl Iterator<Item=Statement<'tcx>> + TrustedLen {
     let mut set_discriminant = None;
     let active_field_index = match kind {
@@ -29,7 +30,7 @@ pub fn expand_aggregate<'tcx>(
                     },
                     source_info,
                 });
-                lhs = lhs.downcast(adt_def, variant_index);
+                lhs = tcx.mk_place_downcast(lhs, adt_def, variant_index);
             }
             active_field_index
         }
@@ -58,7 +59,7 @@ pub fn expand_aggregate<'tcx>(
             // FIXME(eddyb) `offset` should be u64.
             let offset = i as u32;
             assert_eq!(offset as usize, i);
-            lhs.clone().elem(ProjectionElem::ConstantIndex {
+            tcx.mk_place_elem(lhs.clone(), ProjectionElem::ConstantIndex {
                 offset,
                 // FIXME(eddyb) `min_length` doesn't appear to be used.
                 min_length: offset + 1,
@@ -66,7 +67,7 @@ pub fn expand_aggregate<'tcx>(
             })
         } else {
             let field = Field::new(active_field_index.unwrap_or(i));
-            lhs.clone().field(field, ty)
+            tcx.mk_place_field(lhs.clone(), field, ty)
         };
         Statement {
             source_info,

src/librustc_mir/util/alignment.rs

@@ -38,8 +38,8 @@ fn is_within_packed<'tcx, L>(tcx: TyCtxt<'tcx>, local_decls: &L, place: &Place<'
 where
     L: HasLocalDecls<'tcx>,
 {
-    let mut cursor = &*place.projection;
-    while let [proj_base @ .., elem] = cursor {
+    let mut cursor = place.projection.as_ref();
+    while let &[ref proj_base @ .., elem] = cursor {
         cursor = proj_base;
 
         match elem {

src/librustc_mir/util/def_use.rs

@@ -2,6 +2,7 @@
 
 use rustc::mir::{Body, Local, Location, PlaceElem};
 use rustc::mir::visit::{PlaceContext, MutVisitor, Visitor};
+use rustc::ty::TyCtxt;
 use rustc_index::vec::IndexVec;
 use std::mem;
 
@@ -47,20 +48,26 @@ impl DefUseAnalysis {
         &self.info[local]
     }
 
-    fn mutate_defs_and_uses(&self, local: Local, body: &mut Body<'_>, new_local: Local) {
+    fn mutate_defs_and_uses(
+        &self,
+        local: Local,
+        body: &mut Body<'tcx>,
+        new_local: Local,
+        tcx: TyCtxt<'tcx>,
+    ) {
         for place_use in &self.info[local].defs_and_uses {
-            MutateUseVisitor::new(local,
-                                  new_local,
-                                  body).visit_location(body, place_use.location)
+            MutateUseVisitor::new(local, new_local, body, tcx)
+                .visit_location(body, place_use.location)
         }
     }
 
     // FIXME(pcwalton): this should update the def-use chains.
     pub fn replace_all_defs_and_uses_with(&self,
                                           local: Local,
-                                          body: &mut Body<'_>,
-                                          new_local: Local) {
-        self.mutate_defs_and_uses(local, body, new_local)
+                                          body: &mut Body<'tcx>,
+                                          new_local: Local,
+                                          tcx: TyCtxt<'tcx>) {
+        self.mutate_defs_and_uses(local, body, new_local, tcx)
     }
 }
 
@@ -114,21 +121,28 @@ impl Info {
     }
 }
 
-struct MutateUseVisitor {
+struct MutateUseVisitor<'tcx> {
     query: Local,
     new_local: Local,
+    tcx: TyCtxt<'tcx>,
 }
 
-impl MutateUseVisitor {
-    fn new(query: Local, new_local: Local, _: &Body<'_>) -> MutateUseVisitor {
-        MutateUseVisitor {
-            query,
-            new_local,
-        }
+impl MutateUseVisitor<'tcx> {
+    fn new(
+        query: Local,
+        new_local: Local,
+        _: &Body<'tcx>,
+        tcx: TyCtxt<'tcx>,
+    ) -> MutateUseVisitor<'tcx> {
+        MutateUseVisitor { query, new_local, tcx }
     }
 }
 
-impl MutVisitor<'_> for MutateUseVisitor {
+impl MutVisitor<'tcx> for MutateUseVisitor<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
     fn visit_local(&mut self,
                     local: &mut Local,
                     _context: PlaceContext,

src/librustc_mir/util/elaborate_drops.rs

@@ -200,13 +200,14 @@ where
         variant.fields.iter().enumerate().map(|(i, f)| {
             let field = Field::new(i);
             let subpath = self.elaborator.field_subpath(variant_path, field);
+            let tcx = self.tcx();
 
             assert_eq!(self.elaborator.param_env().reveal, Reveal::All);
-            let field_ty = self.tcx().normalize_erasing_regions(
+            let field_ty = tcx.normalize_erasing_regions(
                 self.elaborator.param_env(),
-                f.ty(self.tcx(), substs),
+                f.ty(tcx, substs),
             );
-            (base_place.clone().field(field, field_ty), subpath)
+            (tcx.mk_place_field(base_place.clone(), field, field_ty), subpath)
         }).collect()
     }
 
@@ -323,7 +324,7 @@ where
         debug!("open_drop_for_tuple({:?}, {:?})", self, tys);
 
         let fields = tys.iter().enumerate().map(|(i, &ty)| {
-            (self.place.clone().field(Field::new(i), ty),
+            (self.tcx().mk_place_field(self.place.clone(), Field::new(i), ty),
              self.elaborator.field_subpath(self.path, Field::new(i)))
         }).collect();
 
@@ -334,7 +335,7 @@ where
     fn open_drop_for_box(&mut self, adt: &'tcx ty::AdtDef, substs: SubstsRef<'tcx>) -> BasicBlock {
         debug!("open_drop_for_box({:?}, {:?}, {:?})", self, adt, substs);
 
-        let interior = self.place.clone().deref();
+        let interior = self.tcx().mk_place_deref(self.place.clone());
         let interior_path = self.elaborator.deref_subpath(self.path);
 
         let succ = self.succ; // FIXME(#43234)
@@ -406,14 +407,19 @@ where
         };
 
         let mut have_otherwise = false;
+        let tcx = self.tcx();
 
-        for (variant_index, discr) in adt.discriminants(self.tcx()) {
+        for (variant_index, discr) in adt.discriminants(tcx) {
             let subpath = self.elaborator.downcast_subpath(
                 self.path, variant_index);
             if let Some(variant_path) = subpath {
-                let base_place = self.place.clone().elem(
-                    ProjectionElem::Downcast(Some(adt.variants[variant_index].ident.name),
-                                             variant_index));
+                let base_place = tcx.mk_place_elem(
+                    self.place.clone(),
+                    ProjectionElem::Downcast(
+                        Some(adt.variants[variant_index].ident.name),
+                        variant_index,
+                    ),
+                );
                 let fields = self.move_paths_for_fields(
                     &base_place,
                     variant_path,
@@ -586,7 +592,7 @@ where
                 BorrowKind::Mut { allow_two_phase_borrow: false },
                 Place {
                     base: PlaceBase::Local(cur),
-                    projection: Box::new([ProjectionElem::Deref]),
+                    projection: tcx.intern_place_elems(&vec![ProjectionElem::Deref]),
                 }
              ),
              Rvalue::BinaryOp(BinOp::Offset, move_(&Place::from(cur)), one))
@@ -594,7 +600,7 @@ where
             (Rvalue::Ref(
                  tcx.lifetimes.re_erased,
                  BorrowKind::Mut { allow_two_phase_borrow: false },
-                 self.place.clone().index(cur)),
+                 tcx.mk_place_index(self.place.clone(), cur)),
              Rvalue::BinaryOp(BinOp::Add, move_(&Place::from(cur)), one))
         };
 
@@ -627,7 +633,7 @@ where
         let loop_block = self.elaborator.patch().new_block(loop_block);
 
         self.elaborator.patch().patch_terminator(drop_block, TerminatorKind::Drop {
-            location: ptr.clone().deref(),
+            location: tcx.mk_place_deref(ptr.clone()),
             target: loop_block,
             unwind: unwind.into_option()
         });
@@ -644,18 +650,27 @@ where
         //     ptr_based_loop
         // }
 
+        let tcx = self.tcx();
+
         if let Some(size) = opt_size {
             let size: u32 = size.try_into().unwrap_or_else(|_| {
                 bug!("move out check isn't implemented for array sizes bigger than u32::MAX");
             });
-            let fields: Vec<(Place<'tcx>, Option<D::Path>)> = (0..size).map(|i| {
-                (self.place.clone().elem(ProjectionElem::ConstantIndex{
+            let fields: Vec<(Place<'tcx>, Option<D::Path>)> = (0..size)
+                .map(|i| {
+                    (
+                        tcx.mk_place_elem(
+                            self.place.clone(),
+                            ProjectionElem::ConstantIndex {
                                 offset: i,
                                 min_length: size,
-                    from_end: false
-                }),
-                 self.elaborator.array_subpath(self.path, i, size))
-            }).collect();
+                                from_end: false,
+                            },
+                        ),
+                        self.elaborator.array_subpath(self.path, i, size),
+                    )
+                })
+                .collect();
 
             if fields.iter().any(|(_,path)| path.is_some()) {
                 let (succ, unwind) = self.drop_ladder_bottom();
@@ -664,7 +679,6 @@ where
         }
 
         let move_ = |place: &Place<'tcx>| Operand::Move(place.clone());
-        let tcx = self.tcx();
         let elem_size = &Place::from(self.new_temp(tcx.types.usize));
         let len = &Place::from(self.new_temp(tcx.types.usize));
 
@@ -900,8 +914,8 @@ where
         );
         let args = adt.variants[VariantIdx::new(0)].fields.iter().enumerate().map(|(i, f)| {
             let field = Field::new(i);
-            let field_ty = f.ty(self.tcx(), substs);
-            Operand::Move(self.place.clone().field(field, field_ty))
+            let field_ty = f.ty(tcx, substs);
+            Operand::Move(tcx.mk_place_field(self.place.clone(), field, field_ty))
         }).collect();
 
         let call = TerminatorKind::Call {

src/librustdoc/clean/mod.rs

@@ -26,9 +26,10 @@ use rustc::ty::{self, DefIdTree, TyCtxt, Region, RegionVid, Ty, AdtKind};
 use rustc::ty::fold::TypeFolder;
 use rustc::ty::layout::VariantIdx;
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
-use syntax::ast::{self, AttrStyle, Ident};
+use syntax::ast::{self, Attribute, AttrStyle, AttrItem, Ident};
 use syntax::attr;
 use syntax_expand::base::MacroKind;
+use syntax::parse::lexer::comments;
 use syntax::source_map::DUMMY_SP;
 use syntax::symbol::{Symbol, kw, sym};
 use syntax_pos::{self, Pos, FileName};
@@ -858,8 +859,31 @@ impl Attributes {
         let mut cfg = Cfg::True;
         let mut doc_line = 0;
 
+        /// Converts `attr` to a normal `#[doc="foo"]` comment, if it is a
+        /// comment like `///` or `/** */`. (Returns `attr` unchanged for
+        /// non-sugared doc attributes.)
+        pub fn with_desugared_doc<T>(attr: &Attribute, f: impl FnOnce(&Attribute) -> T) -> T {
+            if attr.is_sugared_doc {
+                let comment = attr.value_str().unwrap();
+                let meta = attr::mk_name_value_item_str(
+                    Ident::with_dummy_span(sym::doc),
+                    Symbol::intern(&comments::strip_doc_comment_decoration(&comment.as_str())),
+                    DUMMY_SP,
+                );
+                f(&Attribute {
+                    item: AttrItem { path: meta.path, tokens: meta.kind.tokens(meta.span) },
+                    id: attr.id,
+                    style: attr.style,
+                    is_sugared_doc: true,
+                    span: attr.span,
+                })
+            } else {
+                f(attr)
+            }
+        }
+
         let other_attrs = attrs.iter().filter_map(|attr| {
-            attr.with_desugared_doc(|attr| {
+            with_desugared_doc(attr, |attr| {
                 if attr.check_name(sym::doc) {
                     if let Some(mi) = attr.meta() {
                         if let Some(value) = mi.value_str() {

src/librustdoc/html/static/main.js

@@ -79,7 +79,7 @@ function getSearchElement() {
                      "derive",
                      "traitalias"];
 
-    var disableShortcuts = getCurrentValue("rustdoc-disable-shortcuts") !== "true";
+    var disableShortcuts = getCurrentValue("rustdoc-disable-shortcuts") === "true";
     var search_input = getSearchInput();
 
     // On the search screen, so you remain on the last tab you opened.

src/libstd/lib.rs

@@ -283,7 +283,7 @@
 #![feature(needs_panic_runtime)]
 #![feature(never_type)]
 #![feature(nll)]
-#![feature(non_exhaustive)]
+#![cfg_attr(bootstrap, feature(non_exhaustive))]
 #![feature(on_unimplemented)]
 #![feature(optin_builtin_traits)]
 #![feature(panic_info_message)]

src/libstd/path.rs

@@ -1363,20 +1363,24 @@ impl PathBuf {
     }
 
     fn _set_extension(&mut self, extension: &OsStr) -> bool {
-        if self.file_name().is_none() {
-            return false;
-        }
-
-        let mut stem = match self.file_stem() {
-            Some(stem) => stem.to_os_string(),
-            None => OsString::new(),
+        let file_stem = match self.file_stem() {
+            None => return false,
+            Some(f) => os_str_as_u8_slice(f),
         };
 
-        if !os_str_as_u8_slice(extension).is_empty() {
-            stem.push(".");
-            stem.push(extension);
+        // truncate until right after the file stem
+        let end_file_stem = file_stem[file_stem.len()..].as_ptr() as usize;
+        let start = os_str_as_u8_slice(&self.inner).as_ptr() as usize;
+        let v = self.as_mut_vec();
+        v.truncate(end_file_stem.wrapping_sub(start));
+
+        // add the new extension, if any
+        let new = os_str_as_u8_slice(extension);
+        if !new.is_empty() {
+            v.reserve_exact(new.len() + 1);
+            v.push(b'.');
+            v.extend_from_slice(new);
         }
-        self.set_file_name(&stem);
 
         true
     }

src/libstd/sys/unix/fs.rs

@@ -105,11 +105,14 @@ cfg_has_statx! {{
         flags: i32,
         mask: u32,
     ) -> Option<io::Result<FileAttr>> {
-        use crate::sync::atomic::{AtomicBool, Ordering};
+        use crate::sync::atomic::{AtomicU8, Ordering};
 
         // Linux kernel prior to 4.11 or glibc prior to glibc 2.28 don't support `statx`
-        // We store the availability in a global to avoid unnecessary syscalls
-        static HAS_STATX: AtomicBool = AtomicBool::new(true);
+        // We store the availability in global to avoid unnecessary syscalls.
+        // 0: Unknown
+        // 1: Not available
+        // 2: Available
+        static STATX_STATE: AtomicU8 = AtomicU8::new(0);
         syscall! {
             fn statx(
                 fd: c_int,
@@ -120,21 +123,33 @@ cfg_has_statx! {{
             ) -> c_int
         }
 
-        if !HAS_STATX.load(Ordering::Relaxed) {
+        match STATX_STATE.load(Ordering::Relaxed) {
+            0 => {
+                // It is a trick to call `statx` with NULL pointers to check if the syscall
+                // is available. According to the manual, it is expected to fail with EFAULT.
+                // We do this mainly for performance, since it is nearly hundreds times
+                // faster than a normal successfull call.
+                let err = cvt(statx(0, ptr::null(), 0, libc::STATX_ALL, ptr::null_mut()))
+                    .err()
+                    .and_then(|e| e.raw_os_error());
+                // We don't check `err == Some(libc::ENOSYS)` because the syscall may be limited
+                // and returns `EPERM`. Listing all possible errors seems not a good idea.
+                // See: https://github.com/rust-lang/rust/issues/65662
+                if err != Some(libc::EFAULT) {
+                    STATX_STATE.store(1, Ordering::Relaxed);
                     return None;
                 }
+                STATX_STATE.store(2, Ordering::Relaxed);
+            }
+            1 => return None,
+            _ => {}
+        }
 
         let mut buf: libc::statx = mem::zeroed();
-        let ret = cvt(statx(fd, path, flags, mask, &mut buf));
-        match ret {
-            Err(err) => match err.raw_os_error() {
-                Some(libc::ENOSYS) => {
-                    HAS_STATX.store(false, Ordering::Relaxed);
-                    return None;
+        if let Err(err) = cvt(statx(fd, path, flags, mask, &mut buf)) {
+            return Some(Err(err));
         }
-                _ => return Some(Err(err)),
-            }
-            Ok(_) => {
+
         // We cannot fill `stat64` exhaustively because of private padding fields.
         let mut stat: stat64 = mem::zeroed();
         // `c_ulong` on gnu-mips, `dev_t` otherwise
@@ -163,8 +178,6 @@ cfg_has_statx! {{
 
         Some(Ok(FileAttr { stat, statx_extra_fields: Some(extra) }))
     }
-        }
-    }
 
 } else {
     #[derive(Clone)]

src/libsyntax/attr/mod.rs

@@ -13,8 +13,8 @@ use crate::ast::{AttrItem, AttrId, AttrStyle, Name, Ident, Path, PathSegment};
 use crate::ast::{MetaItem, MetaItemKind, NestedMetaItem};
 use crate::ast::{Lit, LitKind, Expr, Item, Local, Stmt, StmtKind, GenericParam};
 use crate::mut_visit::visit_clobber;
-use crate::source_map::{BytePos, Spanned, DUMMY_SP};
-use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
+use crate::source_map::{BytePos, Spanned};
+use crate::parse::lexer::comments::doc_comment_style;
 use crate::parse::parser::Parser;
 use crate::parse::PResult;
 use crate::parse::token::{self, Token};
@@ -312,31 +312,6 @@ impl Attribute {
             span: self.span,
         })
     }
-
-    /// Converts `self` to a normal `#[doc="foo"]` comment, if it is a
-    /// comment like `///` or `/** */`. (Returns `self` unchanged for
-    /// non-sugared doc attributes.)
-    pub fn with_desugared_doc<T, F>(&self, f: F) -> T where
-        F: FnOnce(&Attribute) -> T,
-    {
-        if self.is_sugared_doc {
-            let comment = self.value_str().unwrap();
-            let meta = mk_name_value_item_str(
-                Ident::with_dummy_span(sym::doc),
-                Symbol::intern(&strip_doc_comment_decoration(&comment.as_str())),
-                DUMMY_SP,
-            );
-            f(&Attribute {
-                item: AttrItem { path: meta.path, tokens: meta.kind.tokens(meta.span) },
-                id: self.id,
-                style: self.style,
-                is_sugared_doc: true,
-                span: self.span,
-            })
-        } else {
-            f(self)
-        }
-    }
 }
 
 /* Constructors */

src/libsyntax/feature_gate/accepted.rs

@@ -245,8 +245,10 @@ declare_features! (
     (accepted, bind_by_move_pattern_guards, "1.39.0", Some(15287), None),
     /// Allows attributes in formal function parameters.
     (accepted, param_attrs, "1.39.0", Some(60406), None),
-    // Allows macro invocations in `extern {}` blocks.
+    /// Allows macro invocations in `extern {}` blocks.
     (accepted, macros_in_extern, "1.40.0", Some(49476), None),
+    /// Allows future-proofing enums/structs with the `#[non_exhaustive]` attribute (RFC 2008).
+    (accepted, non_exhaustive, "1.40.0", Some(44109), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features

src/libsyntax/feature_gate/active.rs

@@ -383,9 +383,6 @@ declare_features! (
     /// Allows `#[doc(include = "some-file")]`.
     (active, external_doc, "1.22.0", Some(44732), None),
 
-    /// Allows future-proofing enums/structs with the `#[non_exhaustive]` attribute (RFC 2008).
-    (active, non_exhaustive, "1.22.0", Some(44109), None),
-
     /// Allows using `crate` as visibility modifier, synonymous with `pub(crate)`.
     (active, crate_visibility_modifier, "1.23.0", Some(53120), None),
 

src/libsyntax/feature_gate/builtin_attrs.rs

@@ -252,6 +252,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ungated!(path, Normal, template!(NameValueStr: "file")),
     ungated!(no_std, CrateLevel, template!(Word)),
     ungated!(no_implicit_prelude, Normal, template!(Word)),
+    ungated!(non_exhaustive, Whitelisted, template!(Word)),
 
     // Runtime
     ungated!(windows_subsystem, Whitelisted, template!(NameValueStr: "windows|console")),
@@ -314,9 +315,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         test_runner, CrateLevel, template!(List: "path"), custom_test_frameworks,
         "custom test frameworks are an unstable feature",
     ),
-
-    // RFC #2008
-    gated!(non_exhaustive, Whitelisted, template!(Word), experimental!(non_exhaustive)),
     // RFC #1268
     gated!(marker, Normal, template!(Word), marker_trait_attr, experimental!(marker)),
     gated!(

src/libsyntax/json.rs

@@ -25,6 +25,9 @@ use std::sync::{Arc, Mutex};
 
 use rustc_serialize::json::{as_json, as_pretty_json};
 
+#[cfg(test)]
+mod tests;
+
 pub struct JsonEmitter {
     dst: Box<dyn Write + Send>,
     registry: Option<Registry>,
@@ -336,8 +339,8 @@ impl DiagnosticSpan {
 
         DiagnosticSpan {
             file_name: start.file.name.to_string(),
-            byte_start: span.lo().0 - start.file.start_pos.0,
-            byte_end: span.hi().0 - start.file.start_pos.0,
+            byte_start: start.file.original_relative_byte_pos(span.lo()).0,
+            byte_end: start.file.original_relative_byte_pos(span.hi()).0,
             line_start: start.line,
             line_end: end.line,
             column_start: start.col.0 + 1,

src/libsyntax/json/tests.rs

@@ -0,0 +1,186 @@
+use super::*;
+
+use crate::json::JsonEmitter;
+use crate::source_map::{FilePathMapping, SourceMap};
+use crate::tests::Shared;
+use crate::with_default_globals;
+
+use errors::emitter::{ColorConfig, HumanReadableErrorType};
+use errors::Handler;
+use rustc_serialize::json::decode;
+use syntax_pos::{BytePos, Span};
+
+use std::str;
+
+#[derive(RustcDecodable, Debug, PartialEq, Eq)]
+struct TestData {
+    spans: Vec<SpanTestData>,
+}
+
+#[derive(RustcDecodable, Debug, PartialEq, Eq)]
+struct SpanTestData {
+    pub byte_start: u32,
+    pub byte_end: u32,
+    pub line_start: u32,
+    pub column_start: u32,
+    pub line_end: u32,
+    pub column_end: u32,
+}
+
+/// Test the span yields correct positions in JSON.
+fn test_positions(code: &str, span: (u32, u32), expected_output: SpanTestData) {
+    let expected_output = TestData { spans: vec![expected_output] };
+
+    with_default_globals(|| {
+        let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
+        sm.new_source_file(Path::new("test.rs").to_owned().into(), code.to_owned());
+
+        let output = Arc::new(Mutex::new(Vec::new()));
+        let je = JsonEmitter::new(
+            Box::new(Shared { data: output.clone() }),
+            None,
+            sm,
+            true,
+            HumanReadableErrorType::Short(ColorConfig::Never),
+            false,
+        );
+
+        let span = Span::with_root_ctxt(BytePos(span.0), BytePos(span.1));
+        let handler = Handler::with_emitter(true, None, Box::new(je));
+        handler.span_err(span, "foo");
+
+        let bytes = output.lock().unwrap();
+        let actual_output = str::from_utf8(&bytes).unwrap();
+        let actual_output: TestData = decode(actual_output).unwrap();
+
+        assert_eq!(expected_output, actual_output)
+    })
+}
+
+#[test]
+fn empty() {
+    test_positions(
+        " ",
+        (0, 1),
+        SpanTestData {
+            byte_start: 0,
+            byte_end: 1,
+            line_start: 1,
+            column_start: 1,
+            line_end: 1,
+            column_end: 2,
+        },
+    )
+}
+
+#[test]
+fn bom() {
+    test_positions(
+        "\u{feff} ",
+        (0, 1),
+        SpanTestData {
+            byte_start: 3,
+            byte_end: 4,
+            line_start: 1,
+            column_start: 1,
+            line_end: 1,
+            column_end: 2,
+        },
+    )
+}
+
+#[test]
+fn lf_newlines() {
+    test_positions(
+        "\nmod foo;\nmod bar;\n",
+        (5, 12),
+        SpanTestData {
+            byte_start: 5,
+            byte_end: 12,
+            line_start: 2,
+            column_start: 5,
+            line_end: 3,
+            column_end: 3,
+        },
+    )
+}
+
+#[test]
+fn crlf_newlines() {
+    test_positions(
+        "\r\nmod foo;\r\nmod bar;\r\n",
+        (5, 12),
+        SpanTestData {
+            byte_start: 6,
+            byte_end: 14,
+            line_start: 2,
+            column_start: 5,
+            line_end: 3,
+            column_end: 3,
+        },
+    )
+}
+
+#[test]
+fn crlf_newlines_with_bom() {
+    test_positions(
+        "\u{feff}\r\nmod foo;\r\nmod bar;\r\n",
+        (5, 12),
+        SpanTestData {
+            byte_start: 9,
+            byte_end: 17,
+            line_start: 2,
+            column_start: 5,
+            line_end: 3,
+            column_end: 3,
+        },
+    )
+}
+
+#[test]
+fn span_before_crlf() {
+    test_positions(
+        "foo\r\nbar",
+        (2, 3),
+        SpanTestData {
+            byte_start: 2,
+            byte_end: 3,
+            line_start: 1,
+            column_start: 3,
+            line_end: 1,
+            column_end: 4,
+        },
+    )
+}
+
+#[test]
+fn span_on_crlf() {
+    test_positions(
+        "foo\r\nbar",
+        (3, 4),
+        SpanTestData {
+            byte_start: 3,
+            byte_end: 5,
+            line_start: 1,
+            column_start: 4,
+            line_end: 2,
+            column_end: 1,
+        },
+    )
+}
+
+#[test]
+fn span_after_crlf() {
+    test_positions(
+        "foo\r\nbar",
+        (4, 5),
+        SpanTestData {
+            byte_start: 5,
+            byte_end: 6,
+            line_start: 2,
+            column_start: 1,
+            line_end: 2,
+            column_end: 2,
+        },
+    )
+}

src/libsyntax/lib.rs

@@ -31,23 +31,6 @@ mod tests;
 
 pub const MACRO_ARGUMENTS: Option<&'static str> = Some("macro arguments");
 
-// A variant of 'panictry!' that works on a Vec<Diagnostic> instead of a single DiagnosticBuilder.
-macro_rules! panictry_buffer {
-    ($handler:expr, $e:expr) => ({
-        use std::result::Result::{Ok, Err};
-        use errors::FatalError;
-        match $e {
-            Ok(e) => e,
-            Err(errs) => {
-                for e in errs {
-                    $handler.emit_diagnostic(&e);
-                }
-                FatalError.raise()
-            }
-        }
-    })
-}
-
 #[macro_export]
 macro_rules! unwrap_or {
     ($opt:expr, $default:expr) => {

src/libsyntax/parse/lexer/comments.rs

@@ -176,7 +176,7 @@ fn split_block_comment_into_lines(
 
 // it appears this function is called only from pprust... that's
 // probably not a good thing.
-pub fn gather_comments(sess: &ParseSess, path: FileName, src: String) -> Vec<Comment> {
+crate fn gather_comments(sess: &ParseSess, path: FileName, src: String) -> Vec<Comment> {
     let cm = SourceMap::new(sess.source_map().path_mapping().clone());
     let source_file = cm.new_source_file(path, src);
     let text = (*source_file.src.as_ref().unwrap()).clone();

src/libsyntax/parse/lexer/tokentrees.rs

@@ -1,8 +1,9 @@
 use rustc_data_structures::fx::FxHashMap;
 use syntax_pos::Span;
 
+use super::{StringReader, UnmatchedBrace};
+
 use crate::print::pprust::token_to_string;
-use crate::parse::lexer::{StringReader, UnmatchedBrace};
 use crate::parse::token::{self, Token};
 use crate::parse::PResult;
 use crate::tokenstream::{DelimSpan, IsJoint::{self, *}, TokenStream, TokenTree, TreeAndJoint};

src/libsyntax/parse/mod.rs

@@ -59,6 +59,23 @@ pub enum DirectoryOwnership {
 // uses a HOF to parse anything, and <source> includes file and
 // `source_str`.
 
+/// A variant of 'panictry!' that works on a Vec<Diagnostic> instead of a single DiagnosticBuilder.
+macro_rules! panictry_buffer {
+    ($handler:expr, $e:expr) => ({
+        use std::result::Result::{Ok, Err};
+        use errors::FatalError;
+        match $e {
+            Ok(e) => e,
+            Err(errs) => {
+                for e in errs {
+                    $handler.emit_diagnostic(&e);
+                }
+                FatalError.raise()
+            }
+        }
+    })
+}
+
 pub fn parse_crate_from_file<'a>(input: &Path, sess: &'a ParseSess) -> PResult<'a, ast::Crate> {
     let mut parser = new_parser_from_file(sess, input);
     parser.parse_crate_mod()

src/libsyntax/parse/parser.rs

@@ -1368,25 +1368,6 @@ impl<'a> Parser<'a> {
             }
         }
     }
-
-    fn report_invalid_macro_expansion_item(&self) {
-        self.struct_span_err(
-            self.prev_span,
-            "macros that expand to items must be delimited with braces or followed by a semicolon",
-        ).multipart_suggestion(
-            "change the delimiters to curly braces",
-            vec![
-                (self.prev_span.with_hi(self.prev_span.lo() + BytePos(1)), String::from(" {")),
-                (self.prev_span.with_lo(self.prev_span.hi() - BytePos(1)), '}'.to_string()),
-            ],
-            Applicability::MaybeIncorrect,
-        ).span_suggestion(
-            self.sess.source_map().next_point(self.prev_span),
-            "add a semicolon",
-            ';'.to_string(),
-            Applicability::MaybeIncorrect,
-        ).emit();
-    }
 }
 
 pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, handler: &errors::Handler) {

src/libsyntax/parse/parser/item.rs

@@ -19,6 +19,7 @@ use log::debug;
 use std::mem;
 use rustc_target::spec::abi::Abi;
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId, StashKey};
+use syntax_pos::BytePos;
 
 /// Whether the type alias or associated type is a concrete type or an opaque type.
 #[derive(Debug)]
@@ -1739,6 +1740,25 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn report_invalid_macro_expansion_item(&self) {
+        self.struct_span_err(
+            self.prev_span,
+            "macros that expand to items must be delimited with braces or followed by a semicolon",
+        ).multipart_suggestion(
+            "change the delimiters to curly braces",
+            vec![
+                (self.prev_span.with_hi(self.prev_span.lo() + BytePos(1)), String::from(" {")),
+                (self.prev_span.with_lo(self.prev_span.hi() - BytePos(1)), '}'.to_string()),
+            ],
+            Applicability::MaybeIncorrect,
+        ).span_suggestion(
+            self.sess.source_map().next_point(self.prev_span),
+            "add a semicolon",
+            ';'.to_string(),
+            Applicability::MaybeIncorrect,
+        ).emit();
+    }
+
     fn mk_item(&self, span: Span, ident: Ident, kind: ItemKind, vis: Visibility,
                attrs: Vec<Attribute>) -> P<Item> {
         P(Item {

src/libsyntax/source_map.rs

@@ -283,6 +283,7 @@ impl SourceMap {
         mut file_local_lines: Vec<BytePos>,
         mut file_local_multibyte_chars: Vec<MultiByteChar>,
         mut file_local_non_narrow_chars: Vec<NonNarrowChar>,
+        mut file_local_normalized_pos: Vec<NormalizedPos>,
     ) -> Lrc<SourceFile> {
         let start_pos = self.next_start_pos();
 
@@ -301,6 +302,10 @@ impl SourceMap {
             *swc = *swc + start_pos;
         }
 
+        for nc in &mut file_local_normalized_pos {
+            nc.pos = nc.pos + start_pos;
+        }
+
         let source_file = Lrc::new(SourceFile {
             name: filename,
             name_was_remapped,
@@ -314,6 +319,7 @@ impl SourceMap {
             lines: file_local_lines,
             multibyte_chars: file_local_multibyte_chars,
             non_narrow_chars: file_local_non_narrow_chars,
+            normalized_pos: file_local_normalized_pos,
             name_hash,
         });
 

src/libsyntax/tests.rs

@@ -111,8 +111,8 @@ struct SpanLabel {
     label: &'static str,
 }
 
-struct Shared<T: Write> {
-    data: Arc<Mutex<T>>,
+crate struct Shared<T: Write> {
+    pub data: Arc<Mutex<T>>,
 }
 
 impl<T: Write> Write for Shared<T> {

src/libsyntax_pos/lib.rs

@@ -9,7 +9,7 @@
 #![feature(const_fn)]
 #![feature(crate_visibility_modifier)]
 #![feature(nll)]
-#![feature(non_exhaustive)]
+#![cfg_attr(bootstrap, feature(non_exhaustive))]
 #![feature(optin_builtin_traits)]
 #![feature(rustc_attrs)]
 #![cfg_attr(bootstrap, feature(proc_macro_hygiene))]
@@ -855,6 +855,15 @@ impl Sub<BytePos> for NonNarrowChar {
     }
 }
 
+/// Identifies an offset of a character that was normalized away from `SourceFile`.
+#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq, Debug)]
+pub struct NormalizedPos {
+    /// The absolute offset of the character in the `SourceMap`.
+    pub pos: BytePos,
+    /// The difference between original and normalized string at position.
+    pub diff: u32,
+}
+
 /// The state of the lazy external source loading mechanism of a `SourceFile`.
 #[derive(PartialEq, Eq, Clone)]
 pub enum ExternalSource {
@@ -918,6 +927,8 @@ pub struct SourceFile {
     pub multibyte_chars: Vec<MultiByteChar>,
     /// Width of characters that are not narrow in the source code.
     pub non_narrow_chars: Vec<NonNarrowChar>,
+    /// Locations of characters removed during normalization.
+    pub normalized_pos: Vec<NormalizedPos>,
     /// A hash of the filename, used for speeding up hashing in incremental compilation.
     pub name_hash: u128,
 }
@@ -984,6 +995,9 @@ impl Encodable for SourceFile {
             })?;
             s.emit_struct_field("name_hash", 8, |s| {
                 self.name_hash.encode(s)
+            })?;
+            s.emit_struct_field("normalized_pos", 9, |s| {
+                self.normalized_pos.encode(s)
             })
         })
     }
@@ -1034,6 +1048,8 @@ impl Decodable for SourceFile {
                 d.read_struct_field("non_narrow_chars", 7, |d| Decodable::decode(d))?;
             let name_hash: u128 =
                 d.read_struct_field("name_hash", 8, |d| Decodable::decode(d))?;
+            let normalized_pos: Vec<NormalizedPos> =
+                d.read_struct_field("normalized_pos", 9, |d| Decodable::decode(d))?;
             Ok(SourceFile {
                 name,
                 name_was_remapped,
@@ -1050,6 +1066,7 @@ impl Decodable for SourceFile {
                 lines,
                 multibyte_chars,
                 non_narrow_chars,
+                normalized_pos,
                 name_hash,
             })
         })
@@ -1068,8 +1085,7 @@ impl SourceFile {
                unmapped_path: FileName,
                mut src: String,
                start_pos: BytePos) -> Result<SourceFile, OffsetOverflowError> {
-        remove_bom(&mut src);
-        normalize_newlines(&mut src);
+        let normalized_pos = normalize_src(&mut src, start_pos);
 
         let src_hash = {
             let mut hasher: StableHasher = StableHasher::new();
@@ -1102,6 +1118,7 @@ impl SourceFile {
             lines,
             multibyte_chars,
             non_narrow_chars,
+            normalized_pos,
             name_hash,
         })
     }
@@ -1228,12 +1245,44 @@ impl SourceFile {
     pub fn contains(&self, byte_pos: BytePos) -> bool {
         byte_pos >= self.start_pos && byte_pos <= self.end_pos
     }
+
+    /// Calculates the original byte position relative to the start of the file
+    /// based on the given byte position.
+    pub fn original_relative_byte_pos(&self, pos: BytePos) -> BytePos {
+
+        // Diff before any records is 0. Otherwise use the previously recorded
+        // diff as that applies to the following characters until a new diff
+        // is recorded.
+        let diff = match self.normalized_pos.binary_search_by(
+                            |np| np.pos.cmp(&pos)) {
+            Ok(i) => self.normalized_pos[i].diff,
+            Err(i) if i == 0 => 0,
+            Err(i) => self.normalized_pos[i-1].diff,
+        };
+
+        BytePos::from_u32(pos.0 - self.start_pos.0 + diff)
+    }
+}
+
+/// Normalizes the source code and records the normalizations.
+fn normalize_src(src: &mut String, start_pos: BytePos) -> Vec<NormalizedPos> {
+    let mut normalized_pos = vec![];
+    remove_bom(src, &mut normalized_pos);
+    normalize_newlines(src, &mut normalized_pos);
+
+    // Offset all the positions by start_pos to match the final file positions.
+    for np in &mut normalized_pos {
+        np.pos.0 += start_pos.0;
+    }
+
+    normalized_pos
 }
 
 /// Removes UTF-8 BOM, if any.
-fn remove_bom(src: &mut String) {
+fn remove_bom(src: &mut String, normalized_pos: &mut Vec<NormalizedPos>) {
     if src.starts_with("\u{feff}") {
         src.drain(..3);
+        normalized_pos.push(NormalizedPos { pos: BytePos(0), diff: 3 });
     }
 }
 
@@ -1241,7 +1290,7 @@ fn remove_bom(src: &mut String) {
 /// Replaces `\r\n` with `\n` in-place in `src`.
 ///
 /// Returns error if there's a lone `\r` in the string
-fn normalize_newlines(src: &mut String) {
+fn normalize_newlines(src: &mut String, normalized_pos: &mut Vec<NormalizedPos>) {
     if !src.as_bytes().contains(&b'\r') {
         return;
     }
@@ -1254,6 +1303,8 @@ fn normalize_newlines(src: &mut String) {
     let mut buf = std::mem::replace(src, String::new()).into_bytes();
     let mut gap_len = 0;
     let mut tail = buf.as_mut_slice();
+    let mut cursor = 0;
+    let original_gap = normalized_pos.last().map_or(0, |l| l.diff);
     loop {
         let idx = match find_crlf(&tail[gap_len..]) {
             None => tail.len(),
@@ -1264,7 +1315,12 @@ fn normalize_newlines(src: &mut String) {
         if tail.len() == gap_len {
             break;
         }
+        cursor += idx - gap_len;
         gap_len += 1;
+        normalized_pos.push(NormalizedPos {
+            pos: BytePos::from_usize(cursor + 1),
+            diff: original_gap + gap_len as u32,
+        });
     }
 
     // Account for removed `\r`.

src/libsyntax_pos/tests.rs

@@ -19,20 +19,25 @@ fn test_lookup_line() {
 
 #[test]
 fn test_normalize_newlines() {
-    fn check(before: &str, after: &str) {
+    fn check(before: &str, after: &str, expected_positions: &[u32]) {
         let mut actual = before.to_string();
-        normalize_newlines(&mut actual);
+        let mut actual_positions = vec![];
+        normalize_newlines(&mut actual, &mut actual_positions);
+        let actual_positions : Vec<_> = actual_positions
+            .into_iter()
+            .map(|nc| nc.pos.0).collect();
         assert_eq!(actual.as_str(), after);
+        assert_eq!(actual_positions, expected_positions);
     }
-    check("", "");
-    check("\n", "\n");
-    check("\r", "\r");
-    check("\r\r", "\r\r");
-    check("\r\n", "\n");
-    check("hello world", "hello world");
-    check("hello\nworld", "hello\nworld");
-    check("hello\r\nworld", "hello\nworld");
-    check("\r\nhello\r\nworld\r\n", "\nhello\nworld\n");
-    check("\r\r\n", "\r\n");
-    check("hello\rworld", "hello\rworld");
+    check("", "", &[]);
+    check("\n", "\n", &[]);
+    check("\r", "\r", &[]);
+    check("\r\r", "\r\r", &[]);
+    check("\r\n", "\n", &[1]);
+    check("hello world", "hello world", &[]);
+    check("hello\nworld", "hello\nworld", &[]);
+    check("hello\r\nworld", "hello\nworld", &[6]);
+    check("\r\nhello\r\nworld\r\n", "\nhello\nworld\n", &[1, 7, 13]);
+    check("\r\r\n", "\r\n", &[2]);
+    check("hello\rworld", "hello\rworld", &[]);
 }

src/test/ui/.gitattributes

@@ -1,3 +1,6 @@
 lexer-crlf-line-endings-string-literal-doc-comment.rs -text
+json-bom-plus-crlf.rs -text
+json-bom-plus-crlf-multifile.rs -text
+json-bom-plus-crlf-multifile-aux.rs -text
 trailing-carriage-return-in-string.rs -text
 *.bin -text

src/test/ui/feature-gates/feature-gate-non_exhaustive.rs

@@ -1,10 +0,0 @@
-//#![feature(non_exhaustive)]
-
-#[non_exhaustive] //~ERROR the `#[non_exhaustive]` attribute is an experimental feature
-pub enum NonExhaustiveEnum {
-    Unit,
-    Tuple(u32),
-    Struct { field: u32 }
-}
-
-fn main() { }

src/test/ui/feature-gates/feature-gate-non_exhaustive.stderr

@@ -1,12 +0,0 @@
-error[E0658]: the `#[non_exhaustive]` attribute is an experimental feature
-  --> $DIR/feature-gate-non_exhaustive.rs:3:1
-   |
-LL | #[non_exhaustive]
-   | ^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/44109
-   = help: add `#![feature(non_exhaustive)]` to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.

src/test/ui/json-bom-plus-crlf-multifile-aux.rs

@@ -0,0 +1,27 @@
+// (This line has BOM so it's ignored by compiletest for directives)
+//
+// ignore-test Not a test. Used by other tests
+// ignore-tidy-cr
+
+// For easier verifying, the byte offsets in this file should match those
+// in the json-bom-plus-crlf.rs - given the actual fn is identical (just with
+// a different, but equally sized name), the easiest way to do this is to
+// ensure the two files are of equal size on disk.
+// Padding............................
+
+// N.B., this file needs CRLF line endings. The .gitattributes file in
+// this directory should enforce it.
+
+pub fn test() {
+
+    let s : String = 1;  // Error in the middle of line.
+
+    let s : String = 1
+    ;  // Error before the newline.
+
+    let s : String =
+1;  // Error after the newline.
+
+    let s : String = (
+    );  // Error spanning the newline.
+}

src/test/ui/json-bom-plus-crlf-multifile.rs

@@ -0,0 +1,12 @@
+// (This line has BOM so it's ignored by compiletest for directives)
+//
+// build-fail
+// compile-flags: --json=diagnostic-short --error-format=json
+// ignore-tidy-cr
+
+#[path = "json-bom-plus-crlf-multifile-aux.rs"]
+mod json_bom_plus_crlf_multifile_aux;
+
+fn main() {
+    json_bom_plus_crlf_multifile_aux::test();
+}

src/test/ui/json-bom-plus-crlf-multifile.stderr

@@ -0,0 +1,86 @@
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:17:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:19:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:23:1: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":801,"byte_end":809,"line_start":25,"line_end":26,"column_start":22,"column_end":6,"is_primary":true,"text":[{"text":"    let s : String = (","highlight_start":22,"highlight_end":23},{"text":"    );  // Error spanning the newline.","highlight_start":1,"highlight_end":6}],"label":"expected struct `std::string::String`, found ()","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `()`","code":null,"level":"note","spans":[],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:25:22: error[E0308]: mismatched types
+"}
+{"message":"aborting due to 4 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to 4 previous errors
+"}

src/test/ui/json-bom-plus-crlf.rs

@@ -0,0 +1,27 @@
+// (This line has BOM so it's ignored by compiletest for directives)
+//
+// build-fail
+// compile-flags: --json=diagnostic-short --error-format=json
+// ignore-tidy-cr
+
+// For easier verifying, the byte offsets in this file should match those
+// in the json_bom_plus_crlf_multifile_aux.rs - given the actual fn is
+// identical (just with a different, but equally sized name), the easiest way
+// to do this is to ensure the two files are of equal size on disk.
+
+// N.B., this file needs CRLF line endings. The .gitattributes file in
+// this directory should enforce it.
+
+fn main() {
+
+    let s : String = 1;  // Error in the middle of line.
+
+    let s : String = 1
+    ;  // Error before the newline.
+
+    let s : String =
+1;  // Error after the newline.
+
+    let s : String = (
+    );  // Error spanning the newline.
+}

src/test/ui/json-bom-plus-crlf.stderr

@@ -0,0 +1,86 @@
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:17:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:19:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:23:1: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":801,"byte_end":809,"line_start":25,"line_end":26,"column_start":22,"column_end":6,"is_primary":true,"text":[{"text":"    let s : String = (","highlight_start":22,"highlight_end":23},{"text":"    );  // Error spanning the newline.","highlight_start":1,"highlight_end":6}],"label":"expected struct `std::string::String`, found ()","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `()`","code":null,"level":"note","spans":[],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:25:22: error[E0308]: mismatched types
+"}
+{"message":"aborting due to 4 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to 4 previous errors
+"}

src/test/ui/rfc-2008-non-exhaustive/auxiliary/enums.rs

@@ -1,5 +1,4 @@
 #![crate_type = "rlib"]
-#![feature(non_exhaustive)]
 
 #[non_exhaustive]
 pub enum NonExhaustiveEnum {

src/test/ui/rfc-2008-non-exhaustive/auxiliary/structs.rs

@@ -1,5 +1,3 @@
-#![feature(non_exhaustive)]
-
 #[non_exhaustive]
 pub struct NormalStruct {
     pub first_field: u16,

src/test/ui/rfc-2008-non-exhaustive/auxiliary/variants.rs

@@ -1,5 +1,4 @@
 #![crate_type = "rlib"]
-#![feature(non_exhaustive)]
 
 pub enum NonExhaustiveVariants {
     #[non_exhaustive] Unit,

src/test/ui/rfc-2008-non-exhaustive/enum_same_crate.rs

@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(non_exhaustive)]
-
 #[non_exhaustive]
 pub enum NonExhaustiveEnum {
     Unit,

src/test/ui/rfc-2008-non-exhaustive/improper_ctypes/auxiliary/types.rs

@@ -1,5 +1,3 @@
-#![feature(non_exhaustive)]
-
 #[non_exhaustive]
 #[repr(C)]
 pub enum NonExhaustiveEnum {

src/test/ui/rfc-2008-non-exhaustive/improper_ctypes/same_crate_proper.rs

@@ -1,5 +1,4 @@
 // check-pass
-#![feature(non_exhaustive)]
 #![deny(improper_ctypes)]
 
 // This test checks that non-exhaustive types with `#[repr(C)]` are considered proper within

src/test/ui/rfc-2008-non-exhaustive/invalid-attribute.rs

@@ -1,5 +1,3 @@
-#![feature(non_exhaustive)]
-
 #[non_exhaustive(anything)]
 //~^ ERROR malformed `non_exhaustive` attribute
 struct Foo;