]> git.lizzy.rs Git - rust.git/blobdiff - src/librustc_typeck/check/mod.rs
Rollup merge of #62039 - jeremystucki:needless_lifetimes, r=eddyb
[rust.git] / src / librustc_typeck / check / mod.rs
index ae894a114520571baf2af6e0691ff4f267391703..fb7d681a72da7cf286e7f2c82f642a1ec1d6d103 100644 (file)
@@ -93,6 +93,7 @@
 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
+use rustc::hir::ptr::P;
 use crate::middle::lang_items;
 use crate::namespace::Namespace;
 use rustc::infer::{self, InferCtxt, InferOk, InferResult};
 use rustc::mir::interpret::{ConstValue, GlobalId};
 use rustc::traits::{self, ObligationCause, ObligationCauseCode, TraitEngine};
 use rustc::ty::{
-    self, AdtKind, CanonicalUserType, Ty, TyCtxt, Const, GenericParamDefKind, Visibility,
+    self, AdtKind, CanonicalUserType, Ty, TyCtxt, Const, GenericParamDefKind,
     ToPolyTraitRef, ToPredicate, RegionKind, UserType
 };
 use rustc::ty::adjustment::{
 use syntax::ast;
 use syntax::attr;
 use syntax::feature_gate::{GateIssue, emit_feature_err};
-use syntax::ptr::P;
 use syntax::source_map::{DUMMY_SP, original_sp};
-use syntax::symbol::{Symbol, LocalInternedString, kw, sym};
-use syntax::util::lev_distance::find_best_match_for_name;
+use syntax::symbol::{kw, sym};
 
 use std::cell::{Cell, RefCell, Ref, RefMut};
 use std::collections::hash_map::Entry;
 use std::cmp;
-use std::fmt::Display;
 use std::iter;
 use std::mem::replace;
 use std::ops::{self, Deref};
 use crate::lint;
 use crate::util::captures::Captures;
 use crate::util::common::{ErrorReported, indenter};
-use crate::util::nodemap::{DefIdMap, DefIdSet, FxHashMap, FxHashSet, HirIdMap};
+use crate::util::nodemap::{DefIdMap, DefIdSet, FxHashSet, HirIdMap};
 
 pub use self::Expectation::*;
 use self::autoderef::Autoderef;
@@ -162,7 +160,7 @@ pub struct LocalTy<'tcx> {
 
 /// A wrapper for `InferCtxt`'s `in_progress_tables` field.
 #[derive(Copy, Clone)]
-struct MaybeInProgressTables<'a, 'tcx: 'a> {
+struct MaybeInProgressTables<'a, 'tcx> {
     maybe_tables: Option<&'a RefCell<ty::TypeckTables<'tcx>>>,
 }
 
@@ -195,7 +193,7 @@ fn borrow_mut(self) -> RefMut<'a, ty::TypeckTables<'tcx>> {
 /// Here, the function `foo()` and the closure passed to
 /// `bar()` will each have their own `FnCtxt`, but they will
 /// share the inherited fields.
-pub struct Inherited<'a, 'tcx: 'a> {
+pub struct Inherited<'a, 'tcx> {
     infcx: InferCtxt<'a, 'tcx>,
 
     tables: MaybeInProgressTables<'a, 'tcx>,
@@ -219,7 +217,7 @@ pub struct Inherited<'a, 'tcx: 'a> {
 
     deferred_cast_checks: RefCell<Vec<cast::CastCheck<'tcx>>>,
 
-    deferred_generator_interiors: RefCell<Vec<(hir::BodyId, Ty<'tcx>)>>,
+    deferred_generator_interiors: RefCell<Vec<(hir::BodyId, Ty<'tcx>, hir::GeneratorKind)>>,
 
     // Opaque types found in explicit return types and their
     // associated fresh inference variable. Writeback resolves these
@@ -514,7 +512,7 @@ fn find_breakable(&mut self, target_id: hir::HirId) -> &mut BreakableCtxt<'tcx>
     }
 }
 
-pub struct FnCtxt<'a, 'tcx: 'a> {
+pub struct FnCtxt<'a, 'tcx> {
     body_id: hir::HirId,
 
     /// The parameter environment used for proving trait obligations
@@ -529,6 +527,8 @@ pub struct FnCtxt<'a, 'tcx: 'a> {
     /// checking this function. On exit, if we find that *more* errors
     /// have been reported, we will skip regionck and other work that
     /// expects the types within the function to be consistent.
+    // FIXME(matthewjasper) This should not exist, and it's not correct
+    // if type checking is run in parallel.
     err_count_on_creation: usize,
 
     ret_coercion: Option<RefCell<DynamicCoerceMany<'tcx>>>,
@@ -624,7 +624,7 @@ impl Inherited<'a, 'tcx> {
     fn new(infcx: InferCtxt<'a, 'tcx>, def_id: DefId) -> Self {
         let tcx = infcx.tcx;
         let item_id = tcx.hir().as_local_hir_id(def_id);
-        let body_id = item_id.and_then(|id| tcx.hir().maybe_body_owned_by_by_hir_id(id));
+        let body_id = item_id.and_then(|id| tcx.hir().maybe_body_owned_by(id));
         let implicit_region_bound = body_id.map(|body_id| {
             let body = tcx.hir().body(body_id);
             tcx.mk_region(ty::ReScope(region::Scope {
@@ -698,33 +698,31 @@ fn visit_trait_item(&mut self, _: &'tcx hir::TraitItem) { }
     fn visit_impl_item(&mut self, _: &'tcx hir::ImplItem) { }
 }
 
-pub fn check_wf_new<'tcx>(tcx: TyCtxt<'tcx>) -> Result<(), ErrorReported> {
-    tcx.sess.track_errors(|| {
-        let mut visit = wfcheck::CheckTypeWellFormedVisitor::new(tcx);
-        tcx.hir().krate().par_visit_all_item_likes(&mut visit);
-    })
+pub fn check_wf_new(tcx: TyCtxt<'_>) {
+    let mut visit = wfcheck::CheckTypeWellFormedVisitor::new(tcx);
+    tcx.hir().krate().par_visit_all_item_likes(&mut visit);
 }
 
-fn check_mod_item_types<'tcx>(tcx: TyCtxt<'tcx>, module_def_id: DefId) {
+fn check_mod_item_types(tcx: TyCtxt<'_>, module_def_id: DefId) {
     tcx.hir().visit_item_likes_in_module(module_def_id, &mut CheckItemTypesVisitor { tcx });
 }
 
-fn typeck_item_bodies<'tcx>(tcx: TyCtxt<'tcx>, crate_num: CrateNum) {
+fn typeck_item_bodies(tcx: TyCtxt<'_>, crate_num: CrateNum) {
     debug_assert!(crate_num == LOCAL_CRATE);
     tcx.par_body_owners(|body_owner_def_id| {
         tcx.ensure().typeck_tables_of(body_owner_def_id);
     });
 }
 
-fn check_item_well_formed<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) {
+fn check_item_well_formed(tcx: TyCtxt<'_>, def_id: DefId) {
     wfcheck::check_item_well_formed(tcx, def_id);
 }
 
-fn check_trait_item_well_formed<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) {
+fn check_trait_item_well_formed(tcx: TyCtxt<'_>, def_id: DefId) {
     wfcheck::check_trait_item(tcx, def_id);
 }
 
-fn check_impl_item_well_formed<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) {
+fn check_impl_item_well_formed(tcx: TyCtxt<'_>, def_id: DefId) {
     wfcheck::check_impl_item(tcx, def_id);
 }
 
@@ -744,7 +742,7 @@ pub fn provide(providers: &mut Providers<'_>) {
     };
 }
 
-fn adt_destructor<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<ty::Destructor> {
+fn adt_destructor(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::Destructor> {
     tcx.calculate_dtor(def_id, &mut dropck::check_drop_impl)
 }
 
@@ -757,11 +755,11 @@ fn adt_destructor<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<ty::Destruct
 /// may not succeed. In some cases where this function returns `None`
 /// (notably closures), `typeck_tables(def_id)` would wind up
 /// redirecting to the owning function.
-fn primary_body_of<'tcx>(
-    tcx: TyCtxt<'tcx>,
+fn primary_body_of(
+    tcx: TyCtxt<'_>,
     id: hir::HirId,
-) -> Option<(hir::BodyId, Option<&'tcx hir::FnDecl>)> {
-    match tcx.hir().get_by_hir_id(id) {
+) -> Option<(hir::BodyId, Option<&hir::FnDecl>)> {
+    match tcx.hir().get(id) {
         Node::Item(item) => {
             match item.node {
                 hir::ItemKind::Const(_, body) |
@@ -798,7 +796,7 @@ fn primary_body_of<'tcx>(
     }
 }
 
-fn has_typeck_tables<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool {
+fn has_typeck_tables(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     // Closures' tables come from their outermost function,
     // as they are part of the same "inference environment".
     let outer_def_id = tcx.closure_base_def_id(def_id);
@@ -810,11 +808,11 @@ fn has_typeck_tables<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool {
     primary_body_of(tcx, id).is_some()
 }
 
-fn used_trait_imports<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx DefIdSet {
+fn used_trait_imports(tcx: TyCtxt<'_>, def_id: DefId) -> &DefIdSet {
     &*tcx.typeck_tables_of(def_id).used_trait_imports
 }
 
-fn typeck_tables_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx ty::TypeckTables<'tcx> {
+fn typeck_tables_of(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::TypeckTables<'_> {
     // Closures' tables come from their outermost function,
     // as they are part of the same "inference environment".
     let outer_def_id = tcx.closure_base_def_id(def_id);
@@ -823,7 +821,7 @@ fn typeck_tables_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx ty::TypeckT
     }
 
     let id = tcx.hir().as_local_hir_id(def_id).unwrap();
-    let span = tcx.hir().span_by_hir_id(id);
+    let span = tcx.hir().span(id);
 
     // Figure out what primary body this item has.
     let (body_id, fn_decl) = primary_body_of(tcx, id).unwrap_or_else(|| {
@@ -858,7 +856,8 @@ fn typeck_tables_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx ty::TypeckT
             let revealed_ty = if tcx.features().impl_trait_in_bindings {
                 fcx.instantiate_opaque_types_from_value(
                     id,
-                    &expected_type
+                    &expected_type,
+                    body.value.span,
                 )
             } else {
                 expected_type
@@ -914,14 +913,14 @@ fn typeck_tables_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx ty::TypeckT
     tables
 }
 
-fn check_abi<'tcx>(tcx: TyCtxt<'tcx>, span: Span, abi: Abi) {
+fn check_abi(tcx: TyCtxt<'_>, span: Span, abi: Abi) {
     if !tcx.sess.target.target.is_abi_supported(abi) {
         struct_span_err!(tcx.sess, span, E0570,
             "The ABI `{}` is not supported for the current target", abi).emit()
     }
 }
 
-struct GatherLocalsVisitor<'a, 'tcx: 'a> {
+struct GatherLocalsVisitor<'a, 'tcx> {
     fcx: &'a FnCtxt<'a, 'tcx>,
     parent_id: hir::HirId,
 }
@@ -964,7 +963,8 @@ fn visit_local(&mut self, local: &'tcx hir::Local) {
                 let revealed_ty = if self.fcx.tcx.features().impl_trait_in_bindings {
                     self.fcx.instantiate_opaque_types_from_value(
                         self.parent_id,
-                        &o_ty
+                        &o_ty,
+                        ty.span,
                     )
                 } else {
                     o_ty
@@ -995,10 +995,9 @@ fn visit_pat(&mut self, p: &'tcx hir::Pat) {
         if let PatKind::Binding(_, _, ident, _) = p.node {
             let var_ty = self.assign(p.span, p.hir_id, None);
 
-            let node_id = self.fcx.tcx.hir().hir_to_node_id(p.hir_id);
             if !self.fcx.tcx.features().unsized_locals {
                 self.fcx.require_type_is_sized(var_ty, p.span,
-                                               traits::VariableType(node_id));
+                                               traits::VariableType(p.hir_id));
             }
 
             debug!("Pattern binding {} is assigned to {} with type {:?}",
@@ -1061,7 +1060,11 @@ fn check_fn<'a, 'tcx>(
 
     let declared_ret_ty = fn_sig.output();
     fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType);
-    let revealed_ret_ty = fcx.instantiate_opaque_types_from_value(fn_id, &declared_ret_ty);
+    let revealed_ret_ty = fcx.instantiate_opaque_types_from_value(
+        fn_id,
+        &declared_ret_ty,
+        decl.output.span(),
+    );
     fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(revealed_ret_ty)));
     fn_sig = fcx.tcx.mk_fn_sig(
         fn_sig.inputs().iter().cloned(),
@@ -1073,7 +1076,7 @@ fn check_fn<'a, 'tcx>(
 
     let span = body.value.span;
 
-    if body.is_generator && can_be_generator.is_some() {
+    if body.generator_kind.is_some() && can_be_generator.is_some() {
         let yield_ty = fcx.next_ty_var(TypeVariableOrigin {
             kind: TypeVariableOriginKind::TypeInference,
             span,
@@ -1110,12 +1113,12 @@ fn check_fn<'a, 'tcx>(
     // We insert the deferred_generator_interiors entry after visiting the body.
     // This ensures that all nested generators appear before the entry of this generator.
     // resolve_generator_interiors relies on this property.
-    let gen_ty = if can_be_generator.is_some() && body.is_generator {
+    let gen_ty = if let (Some(_), Some(gen_kind)) = (can_be_generator, body.generator_kind) {
         let interior = fcx.next_ty_var(TypeVariableOrigin {
             kind: TypeVariableOriginKind::MiscVariable,
             span,
         });
-        fcx.deferred_generator_interiors.borrow_mut().push((body.id(), interior));
+        fcx.deferred_generator_interiors.borrow_mut().push((body.id(), interior, gen_kind));
         Some(GeneratorTypes {
             yield_ty: fcx.yield_ty.unwrap(),
             interior,
@@ -1195,7 +1198,7 @@ fn check_fn<'a, 'tcx>(
                 }
 
                 let inputs = fn_sig.inputs();
-                let span = fcx.tcx.hir().span_by_hir_id(fn_id);
+                let span = fcx.tcx.hir().span(fn_id);
                 if inputs.len() == 1 {
                     let arg_is_panic_info = match inputs[0].sty {
                         ty::Ref(region, ty, mutbl) => match ty.sty {
@@ -1216,7 +1219,7 @@ fn check_fn<'a, 'tcx>(
                         );
                     }
 
-                    if let Node::Item(item) = fcx.tcx.hir().get_by_hir_id(fn_id) {
+                    if let Node::Item(item) = fcx.tcx.hir().get(fn_id) {
                         if let ItemKind::Fn(_, _, ref generics, _) = item.node {
                             if !generics.params.is_empty() {
                                 fcx.tcx.sess.span_err(
@@ -1248,7 +1251,7 @@ fn check_fn<'a, 'tcx>(
                 }
 
                 let inputs = fn_sig.inputs();
-                let span = fcx.tcx.hir().span_by_hir_id(fn_id);
+                let span = fcx.tcx.hir().span(fn_id);
                 if inputs.len() == 1 {
                     let arg_is_alloc_layout = match inputs[0].sty {
                         ty::Adt(ref adt, _) => {
@@ -1264,7 +1267,7 @@ fn check_fn<'a, 'tcx>(
                         );
                     }
 
-                    if let Node::Item(item) = fcx.tcx.hir().get_by_hir_id(fn_id) {
+                    if let Node::Item(item) = fcx.tcx.hir().get(fn_id) {
                         if let ItemKind::Fn(_, _, ref generics, _) = item.node {
                             if !generics.params.is_empty() {
                                 fcx.tcx.sess.span_err(
@@ -1288,7 +1291,7 @@ fn check_fn<'a, 'tcx>(
     (fcx, gen_ty)
 }
 
-fn check_struct<'tcx>(tcx: TyCtxt<'tcx>, id: hir::HirId, span: Span) {
+fn check_struct(tcx: TyCtxt<'_>, id: hir::HirId, span: Span) {
     let def_id = tcx.hir().local_def_id_from_hir_id(id);
     let def = tcx.adt_def(def_id);
     def.destructor(tcx); // force the destructor to be evaluated
@@ -1302,7 +1305,7 @@ fn check_struct<'tcx>(tcx: TyCtxt<'tcx>, id: hir::HirId, span: Span) {
     check_packed(tcx, span, def_id);
 }
 
-fn check_union<'tcx>(tcx: TyCtxt<'tcx>, id: hir::HirId, span: Span) {
+fn check_union(tcx: TyCtxt<'_>, id: hir::HirId, span: Span) {
     let def_id = tcx.hir().local_def_id_from_hir_id(id);
     let def = tcx.adt_def(def_id);
     def.destructor(tcx); // force the destructor to be evaluated
@@ -1450,8 +1453,8 @@ fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: DefId, span: Span)
     };
     let param_env = ty::ParamEnv::reveal_all();
     if let Ok(static_) = tcx.const_eval(param_env.and(cid)) {
-        let alloc = if let ConstValue::ByRef(_, allocation) = static_.val {
-            allocation
+        let alloc = if let ConstValue::ByRef { alloc, .. } = static_.val {
+            alloc
         } else {
             bug!("Matching on non-ByRef static")
         };
@@ -1464,14 +1467,14 @@ fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: DefId, span: Span)
     }
 }
 
-fn check_on_unimplemented<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, item: &hir::Item) {
+fn check_on_unimplemented(tcx: TyCtxt<'_>, trait_def_id: DefId, item: &hir::Item) {
     let item_def_id = tcx.hir().local_def_id_from_hir_id(item.hir_id);
     // an error would be reported if this fails.
     let _ = traits::OnUnimplementedDirective::of_item(tcx, trait_def_id, item_def_id);
 }
 
-fn report_forbidden_specialization<'tcx>(
-    tcx: TyCtxt<'tcx>,
+fn report_forbidden_specialization(
+    tcx: TyCtxt<'_>,
     impl_item: &hir::ImplItem,
     parent_impl: DefId,
 ) {
@@ -1687,7 +1690,7 @@ fn check_impl_items_against_trait<'tcx>(
 /// Checks whether a type can be represented in memory. In particular, it
 /// identifies types that contain themselves without indirection through a
 /// pointer, which would mean their size is unbounded.
-fn check_representable<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, item_def_id: DefId) -> bool {
+fn check_representable(tcx: TyCtxt<'_>, sp: Span, item_def_id: DefId) -> bool {
     let rty = tcx.type_of(item_def_id);
 
     // Check that it is possible to represent this type. This call identifies
@@ -1709,7 +1712,7 @@ fn check_representable<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, item_def_id: DefId) ->
     return true;
 }
 
-pub fn check_simd<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, def_id: DefId) {
+pub fn check_simd(tcx: TyCtxt<'_>, sp: Span, def_id: DefId) {
     let t = tcx.type_of(def_id);
     if let ty::Adt(def, substs) = t.sty {
         if def.is_struct() {
@@ -1738,7 +1741,7 @@ pub fn check_simd<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, def_id: DefId) {
     }
 }
 
-fn check_packed<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, def_id: DefId) {
+fn check_packed(tcx: TyCtxt<'_>, sp: Span, def_id: DefId) {
     let repr = tcx.adt_def(def_id).repr;
     if repr.packed() {
         for attr in tcx.get_attrs(def_id).iter() {
@@ -1762,7 +1765,7 @@ fn check_packed<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, def_id: DefId) {
     }
 }
 
-fn check_packed_inner<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, stack: &mut Vec<DefId>) -> bool {
+fn check_packed_inner(tcx: TyCtxt<'_>, def_id: DefId, stack: &mut Vec<DefId>) -> bool {
     let t = tcx.type_of(def_id);
     if stack.contains(&def_id) {
         debug!("check_packed_inner: {:?} is recursive", t);
@@ -1790,32 +1793,71 @@ fn check_packed_inner<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, stack: &mut Vec<De
     false
 }
 
-fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, def_id: DefId) {
+/// Emit an error when encountering more or less than one variant in a transparent enum.
+fn bad_variant_count<'tcx>(tcx: TyCtxt<'tcx>, adt: &'tcx ty::AdtDef, sp: Span, did: DefId) {
+    let variant_spans: Vec<_> = adt.variants.iter().map(|variant| {
+        tcx.hir().span_if_local(variant.def_id).unwrap()
+    }).collect();
+    let msg = format!(
+        "needs exactly one variant, but has {}",
+        adt.variants.len(),
+    );
+    let mut err = struct_span_err!(tcx.sess, sp, E0731, "transparent enum {}", msg);
+    err.span_label(sp, &msg);
+    if let &[ref start.., ref end] = &variant_spans[..] {
+        for variant_span in start {
+            err.span_label(*variant_span, "");
+        }
+        err.span_label(*end, &format!("too many variants in `{}`", tcx.def_path_str(did)));
+    }
+    err.emit();
+}
+
+/// Emit an error when encountering more or less than one non-zero-sized field in a transparent
+/// enum.
+fn bad_non_zero_sized_fields<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    adt: &'tcx ty::AdtDef,
+    field_count: usize,
+    field_spans: impl Iterator<Item = Span>,
+    sp: Span,
+) {
+    let msg = format!("needs exactly one non-zero-sized field, but has {}", field_count);
+    let mut err = struct_span_err!(
+        tcx.sess,
+        sp,
+        E0690,
+        "{}transparent {} {}",
+        if adt.is_enum() { "the variant of a " } else { "" },
+        adt.descr(),
+        msg,
+    );
+    err.span_label(sp, &msg);
+    for sp in field_spans {
+        err.span_label(sp, "this field is non-zero-sized");
+    }
+    err.emit();
+}
+
+fn check_transparent(tcx: TyCtxt<'_>, sp: Span, def_id: DefId) {
     let adt = tcx.adt_def(def_id);
     if !adt.repr.transparent() {
         return;
     }
+    let sp = tcx.sess.source_map().def_span(sp);
 
     if adt.is_enum() {
         if !tcx.features().transparent_enums {
-            emit_feature_err(&tcx.sess.parse_sess,
-                             sym::transparent_enums,
-                             sp,
-                             GateIssue::Language,
-                             "transparent enums are unstable");
+            emit_feature_err(
+                &tcx.sess.parse_sess,
+                sym::transparent_enums,
+                sp,
+                GateIssue::Language,
+                "transparent enums are unstable",
+            );
         }
         if adt.variants.len() != 1 {
-            let variant_spans: Vec<_> = adt.variants.iter().map(|variant| {
-                tcx.hir().span_if_local(variant.def_id).unwrap()
-            }).collect();
-            let mut err = struct_span_err!(tcx.sess, sp, E0731,
-                            "transparent enum needs exactly one variant, but has {}",
-                            adt.variants.len());
-            if !variant_spans.is_empty() {
-                err.span_note(variant_spans, &format!("the following variants exist on `{}`",
-                                                      tcx.def_path_str(def_id)));
-            }
-            err.emit();
+            bad_variant_count(tcx, adt, sp, def_id);
             if adt.variants.is_empty() {
                 // Don't bother checking the fields. No variants (and thus no fields) exist.
                 return;
@@ -1843,28 +1885,24 @@ fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, def_id: DefId) {
         (span, zst, align1)
     });
 
-    let non_zst_fields = field_infos.clone().filter(|(_span, zst, _align1)| !*zst);
+    let non_zst_fields = field_infos.clone().filter_map(|(span, zst, _align1)| if !zst {
+        Some(span)
+    } else {
+        None
+    });
     let non_zst_count = non_zst_fields.clone().count();
     if non_zst_count != 1 {
-        let field_spans: Vec<_> = non_zst_fields.map(|(span, _zst, _align1)| span).collect();
-
-        let mut err = struct_span_err!(tcx.sess, sp, E0690,
-                         "{}transparent {} needs exactly one non-zero-sized field, but has {}",
-                         if adt.is_enum() { "the variant of a " } else { "" },
-                         adt.descr(),
-                         non_zst_count);
-        if !field_spans.is_empty() {
-            err.span_note(field_spans,
-                          &format!("the following non-zero-sized fields exist on `{}`:",
-                                   tcx.def_path_str(def_id)));
-        }
-        err.emit();
+        bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, sp);
     }
     for (span, zst, align1) in field_infos {
         if zst && !align1 {
-            span_err!(tcx.sess, span, E0691,
-                      "zero-sized field in transparent {} has alignment larger than 1",
-                      adt.descr());
+            struct_span_err!(
+                tcx.sess,
+                span,
+                E0691,
+                "zero-sized field in transparent {} has alignment larger than 1",
+                adt.descr(),
+            ).span_label(span, "has alignment larger than 1").emit();
         }
     }
 }
@@ -1903,6 +1941,25 @@ pub fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, vs: &'tcx [hir::Variant], i
         }
     }
 
+    if tcx.adt_def(def_id).repr.int.is_none() && tcx.features().arbitrary_enum_discriminant {
+        let is_unit =
+            |var: &hir::Variant| match var.node.data {
+                hir::VariantData::Unit(..) => true,
+                _ => false
+            };
+
+        let has_disr = |var: &hir::Variant| var.node.disr_expr.is_some();
+        let has_non_units = vs.iter().any(|var| !is_unit(var));
+        let disr_units = vs.iter().any(|var| is_unit(&var) && has_disr(&var));
+        let disr_non_unit = vs.iter().any(|var| !is_unit(&var) && has_disr(&var));
+
+        if disr_non_unit || (disr_units && has_non_units) {
+            let mut err = struct_span_err!(tcx.sess, sp, E0732,
+                                           "`#[repr(inttype)]` must be specified");
+            err.emit();
+        }
+    }
+
     let mut disr_vals: Vec<Discr<'tcx>> = Vec::with_capacity(vs.len());
     for ((_, discr), v) in def.discriminants(tcx).zip(vs) {
         // Check for duplicate discriminant values
@@ -1911,11 +1968,11 @@ pub fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, vs: &'tcx [hir::Variant], i
             let variant_i_hir_id = tcx.hir().as_local_hir_id(variant_did).unwrap();
             let variant_i = tcx.hir().expect_variant(variant_i_hir_id);
             let i_span = match variant_i.node.disr_expr {
-                Some(ref expr) => tcx.hir().span_by_hir_id(expr.hir_id),
-                None => tcx.hir().span_by_hir_id(variant_i_hir_id)
+                Some(ref expr) => tcx.hir().span(expr.hir_id),
+                None => tcx.hir().span(variant_i_hir_id)
             };
             let span = match v.node.disr_expr {
-                Some(ref expr) => tcx.hir().span_by_hir_id(expr.hir_id),
+                Some(ref expr) => tcx.hir().span(expr.hir_id),
                 None => v.span
             };
             struct_span_err!(tcx.sess, span, E0081,
@@ -1931,7 +1988,7 @@ pub fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, vs: &'tcx [hir::Variant], i
     check_transparent(tcx, sp, def_id);
 }
 
-fn report_unexpected_variant_res<'tcx>(tcx: TyCtxt<'tcx>, res: Res, span: Span, qpath: &QPath) {
+fn report_unexpected_variant_res(tcx: TyCtxt<'_>, res: Res, span: Span, qpath: &QPath) {
     span_err!(tcx.sess, span, E0533,
               "expected unit struct/variant or constant, found {} `{}`",
               res.descr(),
@@ -2096,8 +2153,8 @@ pub fn sess(&self) -> &Session {
         &self.tcx.sess
     }
 
-    pub fn err_count_since_creation(&self) -> usize {
-        self.tcx.sess.err_count() - self.err_count_on_creation
+    pub fn errors_reported_since_creation(&self) -> bool {
+        self.tcx.sess.err_count() > self.err_count_on_creation
     }
 
     /// Produces warning on the given node, if the current point in the
@@ -2183,7 +2240,7 @@ pub fn tag(&self) -> String {
     pub fn local_ty(&self, span: Span, nid: hir::HirId) -> LocalTy<'tcx> {
         self.locals.borrow().get(&nid).cloned().unwrap_or_else(||
             span_bug!(span, "no type for local variable {}",
-                      self.tcx.hir().hir_to_string(nid))
+                      self.tcx.hir().node_to_string(nid))
         )
     }
 
@@ -2394,6 +2451,7 @@ fn instantiate_opaque_types_from_value<T: TypeFoldable<'tcx>>(
         &self,
         parent_id: hir::HirId,
         value: &T,
+        value_span: Span,
     ) -> T {
         let parent_def_id = self.tcx.hir().local_def_id_from_hir_id(parent_id);
         debug!("instantiate_opaque_types_from_value(parent_def_id={:?}, value={:?})",
@@ -2406,6 +2464,7 @@ fn instantiate_opaque_types_from_value<T: TypeFoldable<'tcx>>(
                 self.body_id,
                 self.param_env,
                 value,
+                value_span,
             )
         );
 
@@ -2519,9 +2578,8 @@ pub fn node_ty(&self, id: hir::HirId) -> Ty<'tcx> {
             Some(&t) => t,
             None if self.is_tainted_by_errors() => self.tcx.types.err,
             None => {
-                let node_id = self.tcx.hir().hir_to_node_id(id);
                 bug!("no type for node {}: {} in fcx {}",
-                     node_id, self.tcx.hir().node_to_string(node_id),
+                     id, self.tcx.hir().node_to_string(id),
                      self.tag());
             }
         }
@@ -2601,9 +2659,9 @@ fn check_casts(&self) {
 
     fn resolve_generator_interiors(&self, def_id: DefId) {
         let mut generators = self.deferred_generator_interiors.borrow_mut();
-        for (body_id, interior) in generators.drain(..) {
+        for (body_id, interior, kind) in generators.drain(..) {
             self.select_obligations_where_possible(false);
-            generator_interior::resolve_interior(self, def_id, body_id, interior);
+            generator_interior::resolve_interior(self, def_id, body_id, interior, kind);
         }
     }
 
@@ -3266,407 +3324,6 @@ fn expected_inputs_for_expected_output(&self,
         expect_args
     }
 
-    // Check field access expressions
-    fn check_field(
-        &self,
-        expr: &'tcx hir::Expr,
-        needs: Needs,
-        base: &'tcx hir::Expr,
-        field: ast::Ident,
-    ) -> Ty<'tcx> {
-        let expr_t = self.check_expr_with_needs(base, needs);
-        let expr_t = self.structurally_resolved_type(base.span,
-                                                     expr_t);
-        let mut private_candidate = None;
-        let mut autoderef = self.autoderef(expr.span, expr_t);
-        while let Some((base_t, _)) = autoderef.next() {
-            match base_t.sty {
-                ty::Adt(base_def, substs) if !base_def.is_enum() => {
-                    debug!("struct named {:?}",  base_t);
-                    let (ident, def_scope) =
-                        self.tcx.adjust_ident_and_get_scope(field, base_def.did, self.body_id);
-                    let fields = &base_def.non_enum_variant().fields;
-                    if let Some(index) = fields.iter().position(|f| f.ident.modern() == ident) {
-                        let field = &fields[index];
-                        let field_ty = self.field_ty(expr.span, field, substs);
-                        // Save the index of all fields regardless of their visibility in case
-                        // of error recovery.
-                        self.write_field_index(expr.hir_id, index);
-                        if field.vis.is_accessible_from(def_scope, self.tcx) {
-                            let adjustments = autoderef.adjust_steps(self, needs);
-                            self.apply_adjustments(base, adjustments);
-                            autoderef.finalize(self);
-
-                            self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span);
-                            return field_ty;
-                        }
-                        private_candidate = Some((base_def.did, field_ty));
-                    }
-                }
-                ty::Tuple(ref tys) => {
-                    let fstr = field.as_str();
-                    if let Ok(index) = fstr.parse::<usize>() {
-                        if fstr == index.to_string() {
-                            if let Some(field_ty) = tys.get(index) {
-                                let adjustments = autoderef.adjust_steps(self, needs);
-                                self.apply_adjustments(base, adjustments);
-                                autoderef.finalize(self);
-
-                                self.write_field_index(expr.hir_id, index);
-                                return field_ty.expect_ty();
-                            }
-                        }
-                    }
-                }
-                _ => {}
-            }
-        }
-        autoderef.unambiguous_final_ty(self);
-
-        if let Some((did, field_ty)) = private_candidate {
-            let struct_path = self.tcx().def_path_str(did);
-            let mut err = struct_span_err!(self.tcx().sess, expr.span, E0616,
-                                           "field `{}` of struct `{}` is private",
-                                           field, struct_path);
-            // Also check if an accessible method exists, which is often what is meant.
-            if self.method_exists(field, expr_t, expr.hir_id, false)
-                && !self.expr_in_place(expr.hir_id)
-            {
-                self.suggest_method_call(
-                    &mut err,
-                    &format!("a method `{}` also exists, call it with parentheses", field),
-                    field,
-                    expr_t,
-                    expr.hir_id,
-                );
-            }
-            err.emit();
-            field_ty
-        } else if field.name == kw::Invalid {
-            self.tcx().types.err
-        } else if self.method_exists(field, expr_t, expr.hir_id, true) {
-            let mut err = type_error_struct!(self.tcx().sess, field.span, expr_t, E0615,
-                               "attempted to take value of method `{}` on type `{}`",
-                               field, expr_t);
-
-            if !self.expr_in_place(expr.hir_id) {
-                self.suggest_method_call(
-                    &mut err,
-                    "use parentheses to call the method",
-                    field,
-                    expr_t,
-                    expr.hir_id
-                );
-            } else {
-                err.help("methods are immutable and cannot be assigned to");
-            }
-
-            err.emit();
-            self.tcx().types.err
-        } else {
-            if !expr_t.is_primitive_ty() {
-                let mut err = self.no_such_field_err(field.span, field, expr_t);
-
-                match expr_t.sty {
-                    ty::Adt(def, _) if !def.is_enum() => {
-                        if let Some(suggested_field_name) =
-                            Self::suggest_field_name(def.non_enum_variant(),
-                                                     &field.as_str(), vec![]) {
-                                err.span_suggestion(
-                                    field.span,
-                                    "a field with a similar name exists",
-                                    suggested_field_name.to_string(),
-                                    Applicability::MaybeIncorrect,
-                                );
-                            } else {
-                                err.span_label(field.span, "unknown field");
-                                let struct_variant_def = def.non_enum_variant();
-                                let field_names = self.available_field_names(struct_variant_def);
-                                if !field_names.is_empty() {
-                                    err.note(&format!("available fields are: {}",
-                                                      self.name_series_display(field_names)));
-                                }
-                            };
-                    }
-                    ty::Array(_, len) => {
-                        if let (Some(len), Ok(user_index)) = (
-                            len.assert_usize(self.tcx),
-                            field.as_str().parse::<u64>()
-                        ) {
-                            let base = self.tcx.sess.source_map()
-                                .span_to_snippet(base.span)
-                                .unwrap_or_else(|_|
-                                    self.tcx.hir().hir_to_pretty_string(base.hir_id));
-                            let help = "instead of using tuple indexing, use array indexing";
-                            let suggestion = format!("{}[{}]", base, field);
-                            let applicability = if len < user_index {
-                                Applicability::MachineApplicable
-                            } else {
-                                Applicability::MaybeIncorrect
-                            };
-                            err.span_suggestion(
-                                expr.span, help, suggestion, applicability
-                            );
-                        }
-                    }
-                    ty::RawPtr(..) => {
-                        let base = self.tcx.sess.source_map()
-                            .span_to_snippet(base.span)
-                            .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
-                        let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
-                        let suggestion = format!("(*{}).{}", base, field);
-                        err.span_suggestion(
-                            expr.span,
-                            &msg,
-                            suggestion,
-                            Applicability::MaybeIncorrect,
-                        );
-                    }
-                    _ => {}
-                }
-                err
-            } else {
-                type_error_struct!(self.tcx().sess, field.span, expr_t, E0610,
-                                   "`{}` is a primitive type and therefore doesn't have fields",
-                                   expr_t)
-            }.emit();
-            self.tcx().types.err
-        }
-    }
-
-    // Return an hint about the closest match in field names
-    fn suggest_field_name(variant: &'tcx ty::VariantDef,
-                          field: &str,
-                          skip: Vec<LocalInternedString>)
-                          -> Option<Symbol> {
-        let names = variant.fields.iter().filter_map(|field| {
-            // ignore already set fields and private fields from non-local crates
-            if skip.iter().any(|x| *x == field.ident.as_str()) ||
-               (!variant.def_id.is_local() && field.vis != Visibility::Public)
-            {
-                None
-            } else {
-                Some(&field.ident.name)
-            }
-        });
-
-        find_best_match_for_name(names, field, None)
-    }
-
-    fn available_field_names(&self, variant: &'tcx ty::VariantDef) -> Vec<ast::Name> {
-        variant.fields.iter().filter(|field| {
-            let def_scope =
-                self.tcx.adjust_ident_and_get_scope(field.ident, variant.def_id, self.body_id).1;
-            field.vis.is_accessible_from(def_scope, self.tcx)
-        })
-        .map(|field| field.ident.name)
-        .collect()
-    }
-
-    fn name_series_display(&self, names: Vec<ast::Name>) -> String {
-        // dynamic limit, to never omit just one field
-        let limit = if names.len() == 6 { 6 } else { 5 };
-        let mut display = names.iter().take(limit)
-            .map(|n| format!("`{}`", n)).collect::<Vec<_>>().join(", ");
-        if names.len() > limit {
-            display = format!("{} ... and {} others", display, names.len() - limit);
-        }
-        display
-    }
-
-    fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS<'_>)
-        -> DiagnosticBuilder<'_> {
-        type_error_struct!(self.tcx().sess, span, expr_t, E0609,
-                           "no field `{}` on type `{}`",
-                           field, expr_t)
-    }
-
-    fn report_unknown_field(
-        &self,
-        ty: Ty<'tcx>,
-        variant: &'tcx ty::VariantDef,
-        field: &hir::Field,
-        skip_fields: &[hir::Field],
-        kind_name: &str,
-    ) {
-        if variant.recovered {
-            return;
-        }
-        let mut err = self.type_error_struct_with_diag(
-            field.ident.span,
-            |actual| match ty.sty {
-                ty::Adt(adt, ..) if adt.is_enum() => {
-                    struct_span_err!(self.tcx.sess, field.ident.span, E0559,
-                                     "{} `{}::{}` has no field named `{}`",
-                                     kind_name, actual, variant.ident, field.ident)
-                }
-                _ => {
-                    struct_span_err!(self.tcx.sess, field.ident.span, E0560,
-                                     "{} `{}` has no field named `{}`",
-                                     kind_name, actual, field.ident)
-                }
-            },
-            ty);
-        // prevent all specified fields from being suggested
-        let skip_fields = skip_fields.iter().map(|ref x| x.ident.as_str());
-        if let Some(field_name) = Self::suggest_field_name(variant,
-                                                           &field.ident.as_str(),
-                                                           skip_fields.collect()) {
-            err.span_suggestion(
-                field.ident.span,
-                "a field with a similar name exists",
-                field_name.to_string(),
-                Applicability::MaybeIncorrect,
-            );
-        } else {
-            match ty.sty {
-                ty::Adt(adt, ..) => {
-                    if adt.is_enum() {
-                        err.span_label(field.ident.span,
-                                       format!("`{}::{}` does not have this field",
-                                               ty, variant.ident));
-                    } else {
-                        err.span_label(field.ident.span,
-                                       format!("`{}` does not have this field", ty));
-                    }
-                    let available_field_names = self.available_field_names(variant);
-                    if !available_field_names.is_empty() {
-                        err.note(&format!("available fields are: {}",
-                                          self.name_series_display(available_field_names)));
-                    }
-                }
-                _ => bug!("non-ADT passed to report_unknown_field")
-            }
-        };
-        err.emit();
-    }
-
-    fn check_expr_struct_fields(
-        &self,
-        adt_ty: Ty<'tcx>,
-        expected: Expectation<'tcx>,
-        expr_id: hir::HirId,
-        span: Span,
-        variant: &'tcx ty::VariantDef,
-        ast_fields: &'tcx [hir::Field],
-        check_completeness: bool,
-    ) -> bool {
-        let tcx = self.tcx;
-
-        let adt_ty_hint =
-            self.expected_inputs_for_expected_output(span, expected, adt_ty, &[adt_ty])
-                .get(0).cloned().unwrap_or(adt_ty);
-        // re-link the regions that EIfEO can erase.
-        self.demand_eqtype(span, adt_ty_hint, adt_ty);
-
-        let (substs, adt_kind, kind_name) = match &adt_ty.sty {
-            &ty::Adt(adt, substs) => {
-                (substs, adt.adt_kind(), adt.variant_descr())
-            }
-            _ => span_bug!(span, "non-ADT passed to check_expr_struct_fields")
-        };
-
-        let mut remaining_fields = variant.fields.iter().enumerate().map(|(i, field)|
-            (field.ident.modern(), (i, field))
-        ).collect::<FxHashMap<_, _>>();
-
-        let mut seen_fields = FxHashMap::default();
-
-        let mut error_happened = false;
-
-        // Type-check each field.
-        for field in ast_fields {
-            let ident = tcx.adjust_ident(field.ident, variant.def_id);
-            let field_type = if let Some((i, v_field)) = remaining_fields.remove(&ident) {
-                seen_fields.insert(ident, field.span);
-                self.write_field_index(field.hir_id, i);
-
-                // We don't look at stability attributes on
-                // struct-like enums (yet...), but it's definitely not
-                // a bug to have constructed one.
-                if adt_kind != AdtKind::Enum {
-                    tcx.check_stability(v_field.did, Some(expr_id), field.span);
-                }
-
-                self.field_ty(field.span, v_field, substs)
-            } else {
-                error_happened = true;
-                if let Some(prev_span) = seen_fields.get(&ident) {
-                    let mut err = struct_span_err!(self.tcx.sess,
-                                                   field.ident.span,
-                                                   E0062,
-                                                   "field `{}` specified more than once",
-                                                   ident);
-
-                    err.span_label(field.ident.span, "used more than once");
-                    err.span_label(*prev_span, format!("first use of `{}`", ident));
-
-                    err.emit();
-                } else {
-                    self.report_unknown_field(adt_ty, variant, field, ast_fields, kind_name);
-                }
-
-                tcx.types.err
-            };
-
-            // Make sure to give a type to the field even if there's
-            // an error, so we can continue type-checking.
-            self.check_expr_coercable_to_type(&field.expr, field_type);
-        }
-
-        // Make sure the programmer specified correct number of fields.
-        if kind_name == "union" {
-            if ast_fields.len() != 1 {
-                tcx.sess.span_err(span, "union expressions should have exactly one field");
-            }
-        } else if check_completeness && !error_happened && !remaining_fields.is_empty() {
-            let len = remaining_fields.len();
-
-            let mut displayable_field_names = remaining_fields
-                                              .keys()
-                                              .map(|ident| ident.as_str())
-                                              .collect::<Vec<_>>();
-
-            displayable_field_names.sort();
-
-            let truncated_fields_error = if len <= 3 {
-                String::new()
-            } else {
-                format!(" and {} other field{}", (len - 3), if len - 3 == 1 {""} else {"s"})
-            };
-
-            let remaining_fields_names = displayable_field_names.iter().take(3)
-                                        .map(|n| format!("`{}`", n))
-                                        .collect::<Vec<_>>()
-                                        .join(", ");
-
-            struct_span_err!(tcx.sess, span, E0063,
-                             "missing field{} {}{} in initializer of `{}`",
-                             if remaining_fields.len() == 1 { "" } else { "s" },
-                             remaining_fields_names,
-                             truncated_fields_error,
-                             adt_ty)
-                .span_label(span, format!("missing {}{}",
-                                          remaining_fields_names,
-                                          truncated_fields_error))
-                .emit();
-        }
-        error_happened
-    }
-
-    fn check_struct_fields_on_error(
-        &self,
-        fields: &'tcx [hir::Field],
-        base_expr: &'tcx Option<P<hir::Expr>>,
-    ) {
-        for field in fields {
-            self.check_expr(&field.expr);
-        }
-        if let Some(ref base) = *base_expr {
-            self.check_expr(&base);
-        }
-    }
-
     pub fn check_struct_path(&self,
                              qpath: &QPath,
                              hir_id: hir::HirId)
@@ -3767,7 +3424,7 @@ fn finish_resolving_struct_path(&self,
         }
     }
 
-    /// Resolves associated value path into a base type and associated constant or method
+    /// Resolves an associated value path into a base type and associated constant, or method
     /// resolution. The newly resolved definition is written into `type_dependent_defs`.
     pub fn resolve_ty_and_res_ufcs<'b>(&self,
                                        qpath: &'b QPath,
@@ -4046,7 +3703,7 @@ fn check_block_with_expected(
     }
 
     fn parent_item_span(&self, id: hir::HirId) -> Option<Span> {
-        let node = self.tcx.hir().get_by_hir_id(self.tcx.hir().get_parent_item(id));
+        let node = self.tcx.hir().get(self.tcx.hir().get_parent_item(id));
         match node {
             Node::Item(&hir::Item {
                 node: hir::ItemKind::Fn(_, _, _, body_id), ..
@@ -4065,43 +3722,43 @@ fn parent_item_span(&self, id: hir::HirId) -> Option<Span> {
     }
 
     /// Given a function block's `HirId`, returns its `FnDecl` if it exists, or `None` otherwise.
-    fn get_parent_fn_decl(&self, blk_id: hir::HirId) -> Option<(hir::FnDecl, ast::Ident)> {
-        let parent = self.tcx.hir().get_by_hir_id(self.tcx.hir().get_parent_item(blk_id));
+    fn get_parent_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl, ast::Ident)> {
+        let parent = self.tcx.hir().get(self.tcx.hir().get_parent_item(blk_id));
         self.get_node_fn_decl(parent).map(|(fn_decl, ident, _)| (fn_decl, ident))
     }
 
     /// Given a function `Node`, return its `FnDecl` if it exists, or `None` otherwise.
-    fn get_node_fn_decl(&self, node: Node<'_>) -> Option<(hir::FnDecl, ast::Ident, bool)> {
+    fn get_node_fn_decl(&self, node: Node<'tcx>) -> Option<(&'tcx hir::FnDecl, ast::Ident, bool)> {
         match node {
             Node::Item(&hir::Item {
                 ident, node: hir::ItemKind::Fn(ref decl, ..), ..
-            }) => decl.clone().and_then(|decl| {
+            }) => {
                 // This is less than ideal, it will not suggest a return type span on any
                 // method called `main`, regardless of whether it is actually the entry point,
                 // but it will still present it as the reason for the expected type.
                 Some((decl, ident, ident.name != sym::main))
-            }),
+            }
             Node::TraitItem(&hir::TraitItem {
                 ident, node: hir::TraitItemKind::Method(hir::MethodSig {
                     ref decl, ..
                 }, ..), ..
-            }) => decl.clone().and_then(|decl| Some((decl, ident, true))),
+            }) => Some((decl, ident, true)),
             Node::ImplItem(&hir::ImplItem {
                 ident, node: hir::ImplItemKind::Method(hir::MethodSig {
                     ref decl, ..
                 }, ..), ..
-            }) => decl.clone().and_then(|decl| Some((decl, ident, false))),
+            }) => Some((decl, ident, false)),
             _ => None,
         }
     }
 
     /// Given a `HirId`, return the `FnDecl` of the method it is enclosed by and whether a
     /// suggestion can be made, `None` otherwise.
-    pub fn get_fn_decl(&self, blk_id: hir::HirId) -> Option<(hir::FnDecl, bool)> {
+    pub fn get_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl, bool)> {
         // Get enclosing Fn, if it is a function or a trait method, unless there's a `loop` or
         // `while` before reaching it, as block tail returns are not available in them.
         self.tcx.hir().get_return_block(blk_id).and_then(|blk_id| {
-            let parent = self.tcx.hir().get_by_hir_id(blk_id);
+            let parent = self.tcx.hir().get(blk_id);
             self.get_node_fn_decl(parent).map(|(fn_decl, _, is_main)| (fn_decl, is_main))
         })
     }
@@ -4283,6 +3940,72 @@ fn suggest_missing_return_type(
         }
     }
 
+    /// A possible error is to forget to add `.await` when using futures:
+    ///
+    /// ```
+    /// #![feature(async_await)]
+    ///
+    /// async fn make_u32() -> u32 {
+    ///     22
+    /// }
+    ///
+    /// fn take_u32(x: u32) {}
+    ///
+    /// async fn foo() {
+    ///     let x = make_u32();
+    ///     take_u32(x);
+    /// }
+    /// ```
+    ///
+    /// This routine checks if the found type `T` implements `Future<Output=U>` where `U` is the
+    /// expected type. If this is the case, and we are inside of an async body, it suggests adding
+    /// `.await` to the tail of the expression.
+    fn suggest_missing_await(
+        &self,
+        err: &mut DiagnosticBuilder<'tcx>,
+        expr: &hir::Expr,
+        expected: Ty<'tcx>,
+        found: Ty<'tcx>,
+    ) {
+        // `.await` is not permitted outside of `async` bodies, so don't bother to suggest if the
+        // body isn't `async`.
+        let item_id = self.tcx().hir().get_parent_node(self.body_id);
+        if let Some(body_id) = self.tcx().hir().maybe_body_owned_by(item_id) {
+            let body = self.tcx().hir().body(body_id);
+            if let Some(hir::GeneratorKind::Async) = body.generator_kind {
+                let sp = expr.span;
+                // Check for `Future` implementations by constructing a predicate to
+                // prove: `<T as Future>::Output == U`
+                let future_trait = self.tcx.lang_items().future_trait().unwrap();
+                let item_def_id = self.tcx.associated_items(future_trait).next().unwrap().def_id;
+                let predicate = ty::Predicate::Projection(ty::Binder::bind(ty::ProjectionPredicate {
+                    // `<T as Future>::Output`
+                    projection_ty: ty::ProjectionTy {
+                        // `T`
+                        substs: self.tcx.mk_substs_trait(
+                            found,
+                            self.fresh_substs_for_item(sp, item_def_id)
+                        ),
+                        // `Future::Output`
+                        item_def_id,
+                    },
+                    ty: expected,
+                }));
+                let obligation = traits::Obligation::new(self.misc(sp), self.param_env, predicate);
+                if self.infcx.predicate_may_hold(&obligation) {
+                    if let Ok(code) = self.sess().source_map().span_to_snippet(sp) {
+                        err.span_suggestion(
+                            sp,
+                            "consider using `.await` here",
+                            format!("{}.await", code),
+                            Applicability::MaybeIncorrect,
+                        );
+                    }
+                }
+            }
+        }
+    }
+
     /// A common error is to add an extra semicolon:
     ///
     /// ```
@@ -4326,52 +4049,6 @@ fn could_remove_semicolon(&self, blk: &'tcx hir::Block, expected_ty: Ty<'tcx>) -
         Some(original_span.with_lo(original_span.hi() - BytePos(1)))
     }
 
-    // Rewrite `SelfCtor` to `Ctor`
-    pub fn rewrite_self_ctor(
-        &self,
-        res: Res,
-        span: Span,
-    ) -> Result<Res, ErrorReported> {
-        let tcx = self.tcx;
-        if let Res::SelfCtor(impl_def_id) = res {
-            let ty = self.impl_self_ty(span, impl_def_id).ty;
-            let adt_def = ty.ty_adt_def();
-
-            match adt_def {
-                Some(adt_def) if adt_def.has_ctor() => {
-                    let variant = adt_def.non_enum_variant();
-                    let ctor_def_id = variant.ctor_def_id.unwrap();
-                    Ok(Res::Def(DefKind::Ctor(CtorOf::Struct, variant.ctor_kind), ctor_def_id))
-                }
-                _ => {
-                    let mut err = tcx.sess.struct_span_err(span,
-                        "the `Self` constructor can only be used with tuple or unit structs");
-                    if let Some(adt_def) = adt_def {
-                        match adt_def.adt_kind() {
-                            AdtKind::Enum => {
-                                err.help("did you mean to use one of the enum's variants?");
-                            },
-                            AdtKind::Struct |
-                            AdtKind::Union => {
-                                err.span_suggestion(
-                                    span,
-                                    "use curly brackets",
-                                    String::from("Self { /* fields */ }"),
-                                    Applicability::HasPlaceholders,
-                                );
-                            }
-                        }
-                    }
-                    err.emit();
-
-                    Err(ErrorReported)
-                }
-            }
-        } else {
-            Ok(res)
-        }
-    }
-
     // Instantiates the given path, which must refer to an item with the given
     // number of type parameters and type.
     pub fn instantiate_value_path(&self,
@@ -4391,12 +4068,8 @@ pub fn instantiate_value_path(&self,
 
         let tcx = self.tcx;
 
-        let res = match self.rewrite_self_ctor(res, span) {
-            Ok(res) => res,
-            Err(ErrorReported) => return (tcx.types.err, res),
-        };
         let path_segs = match res {
-            Res::Local(_) => vec![],
+            Res::Local(_) | Res::SelfCtor(_) => vec![],
             Res::Def(kind, def_id) =>
                 AstConv::def_ids_for_value_path_segments(self, segments, self_ty, kind, def_id),
             _ => bug!("instantiate_value_path on {:?}", res),
@@ -4501,13 +4174,53 @@ pub fn instantiate_value_path(&self,
             tcx.generics_of(*def_id).has_self
         }).unwrap_or(false);
 
+        let (res, self_ctor_substs) = if let Res::SelfCtor(impl_def_id) = res {
+            let ty = self.impl_self_ty(span, impl_def_id).ty;
+            let adt_def = ty.ty_adt_def();
+
+            match ty.sty {
+                ty::Adt(adt_def, substs) if adt_def.has_ctor() => {
+                    let variant = adt_def.non_enum_variant();
+                    let ctor_def_id = variant.ctor_def_id.unwrap();
+                    (
+                        Res::Def(DefKind::Ctor(CtorOf::Struct, variant.ctor_kind), ctor_def_id),
+                        Some(substs),
+                    )
+                }
+                _ => {
+                    let mut err = tcx.sess.struct_span_err(span,
+                        "the `Self` constructor can only be used with tuple or unit structs");
+                    if let Some(adt_def) = adt_def {
+                        match adt_def.adt_kind() {
+                            AdtKind::Enum => {
+                                err.help("did you mean to use one of the enum's variants?");
+                            },
+                            AdtKind::Struct |
+                            AdtKind::Union => {
+                                err.span_suggestion(
+                                    span,
+                                    "use curly brackets",
+                                    String::from("Self { /* fields */ }"),
+                                    Applicability::HasPlaceholders,
+                                );
+                            }
+                        }
+                    }
+                    err.emit();
+
+                    return (tcx.types.err, res)
+                }
+            }
+        } else {
+            (res, None)
+        };
         let def_id = res.def_id();
 
         // The things we are substituting into the type should not contain
         // escaping late-bound regions, and nor should the base type scheme.
         let ty = tcx.type_of(def_id);
 
-        let substs = AstConv::create_substs_for_generic_args(
+        let substs = self_ctor_substs.unwrap_or_else(|| AstConv::create_substs_for_generic_args(
             tcx,
             def_id,
             &[][..],
@@ -4577,7 +4290,7 @@ pub fn instantiate_value_path(&self,
                     }
                 }
             },
-        );
+        ));
         assert!(!substs.has_escaping_bound_vars());
         assert!(!ty.has_escaping_bound_vars());
 
@@ -4638,8 +4351,8 @@ fn check_rustc_args_require_const(&self,
 
         // If our calling expression is indeed the function itself, we're good!
         // If not, generate an error that this can only be called directly.
-        if let Node::Expr(expr) = self.tcx.hir().get_by_hir_id(
-            self.tcx.hir().get_parent_node_by_hir_id(hir_id))
+        if let Node::Expr(expr) = self.tcx.hir().get(
+            self.tcx.hir().get_parent_node(hir_id))
         {
             if let ExprKind::Call(ref callee, ..) = expr.node {
                 if callee.hir_id == hir_id {
@@ -4714,7 +4427,7 @@ fn expr_in_place(&self, mut expr_id: hir::HirId) -> bool {
         let mut contained_in_place = false;
 
         while let hir::Node::Expr(parent_expr) =
-            self.tcx.hir().get_by_hir_id(self.tcx.hir().get_parent_node_by_hir_id(expr_id))
+            self.tcx.hir().get(self.tcx.hir().get_parent_node(expr_id))
         {
             match &parent_expr.node {
                 hir::ExprKind::Assign(lhs, ..) | hir::ExprKind::AssignOp(_, lhs, ..) => {
@@ -4755,7 +4468,7 @@ pub fn check_bounds_are_used<'tcx>(tcx: TyCtxt<'tcx>, generics: &ty::Generics, t
         } else if let ty::Error = leaf_ty.sty {
             // If there is already another error, do not emit
             // an error for not using a type Parameter.
-            assert!(tcx.sess.err_count() > 0);
+            assert!(tcx.sess.has_errors());
             return;
         }
     }
@@ -4767,7 +4480,7 @@ pub fn check_bounds_are_used<'tcx>(tcx: TyCtxt<'tcx>, generics: &ty::Generics, t
     for (&used, param) in types_used.iter().zip(types) {
         if !used {
             let id = tcx.hir().as_local_hir_id(param.def_id).unwrap();
-            let span = tcx.hir().span_by_hir_id(id);
+            let span = tcx.hir().span(id);
             struct_span_err!(tcx.sess, span, E0091, "type parameter `{}` is unused", param.name)
                 .span_label(span, "unused type parameter")
                 .emit();