1 files changed, 39 insertions, 32 deletions

diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index cf420bafe..9cbda95a4 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -17,9 +17,11 @@ use rustc_data_structures::captures::Captures;
 use rustc_data_structures::intern::Interned;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
+use rustc_hir::LangItem;
 use rustc_index::vec::Idx;
 use rustc_macros::HashStable;
 use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::Span;
 use rustc_target::abi::VariantIdx;
 use rustc_target::spec::abi;
 use std::borrow::Cow;
@@ -58,7 +60,7 @@ pub struct FreeRegion {
 #[derive(HashStable)]
 pub enum BoundRegionKind {
     /// An anonymous region parameter for a given fn (&T)
-    BrAnon(u32),
+    BrAnon(u32, Option<Span>),
 
     /// Named region parameters for functions (a in &'a T)
     ///
@@ -81,7 +83,9 @@ pub struct BoundRegion {
 impl BoundRegionKind {
     pub fn is_named(&self) -> bool {
         match *self {
-            BoundRegionKind::BrNamed(_, name) => name != kw::UnderscoreLifetime,
+            BoundRegionKind::BrNamed(_, name) => {
+                name != kw::UnderscoreLifetime && name != kw::Empty
+            }
             _ => false,
         }
     }
@@ -702,7 +706,9 @@ impl<'tcx> ExistentialPredicate<'tcx> {
     }
 }
 
-impl<'tcx> Binder<'tcx, ExistentialPredicate<'tcx>> {
+pub type PolyExistentialPredicate<'tcx> = Binder<'tcx, ExistentialPredicate<'tcx>>;
+
+impl<'tcx> PolyExistentialPredicate<'tcx> {
     /// Given an existential predicate like `?Self: PartialEq<u32>` (e.g., derived from `dyn PartialEq<u32>`),
     /// and a concrete type `self_ty`, returns a full predicate where the existentially quantified variable `?Self`
     /// has been replaced with `self_ty` (e.g., `self_ty: PartialEq<u32>`, in our example).
@@ -716,17 +722,23 @@ impl<'tcx> Binder<'tcx, ExistentialPredicate<'tcx>> {
                 self.rebind(p.with_self_ty(tcx, self_ty)).to_predicate(tcx)
             }
             ExistentialPredicate::AutoTrait(did) => {
-                let trait_ref = self.rebind(ty::TraitRef {
-                    def_id: did,
-                    substs: tcx.mk_substs_trait(self_ty, &[]),
-                });
-                trait_ref.without_const().to_predicate(tcx)
+                let generics = tcx.generics_of(did);
+                let trait_ref = if generics.params.len() == 1 {
+                    tcx.mk_trait_ref(did, [self_ty])
+                } else {
+                    // If this is an ill-formed auto trait, then synthesize
+                    // new error substs for the missing generics.
+                    let err_substs =
+                        ty::InternalSubsts::extend_with_error(tcx, did, &[self_ty.into()]);
+                    tcx.mk_trait_ref(did, err_substs)
+                };
+                self.rebind(trait_ref).without_const().to_predicate(tcx)
             }
         }
     }
 }
 
-impl<'tcx> List<ty::Binder<'tcx, ExistentialPredicate<'tcx>>> {
+impl<'tcx> List<ty::PolyExistentialPredicate<'tcx>> {
     /// Returns the "principal `DefId`" of this set of existential predicates.
     ///
     /// A Rust trait object type consists (in addition to a lifetime bound)
@@ -811,6 +823,13 @@ impl<'tcx> TraitRef<'tcx> {
         TraitRef { def_id, substs }
     }
 
+    pub fn with_self_type(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self {
+        tcx.mk_trait_ref(
+            self.def_id,
+            [self_ty.into()].into_iter().chain(self.substs.iter().skip(1)),
+        )
+    }
+
     /// Returns a `TraitRef` of the form `P0: Foo<P1..Pn>` where `Pi`
     /// are the parameters defined on trait.
     pub fn identity(tcx: TyCtxt<'tcx>, def_id: DefId) -> Binder<'tcx, TraitRef<'tcx>> {
@@ -845,23 +864,6 @@ impl<'tcx> PolyTraitRef<'tcx> {
     pub fn def_id(&self) -> DefId {
         self.skip_binder().def_id
     }
-
-    pub fn to_poly_trait_predicate(&self) -> ty::PolyTraitPredicate<'tcx> {
-        self.map_bound(|trait_ref| ty::TraitPredicate {
-            trait_ref,
-            constness: ty::BoundConstness::NotConst,
-            polarity: ty::ImplPolarity::Positive,
-        })
-    }
-
-    /// Same as [`PolyTraitRef::to_poly_trait_predicate`] but sets a negative polarity instead.
-    pub fn to_poly_trait_predicate_negative_polarity(&self) -> ty::PolyTraitPredicate<'tcx> {
-        self.map_bound(|trait_ref| ty::TraitPredicate {
-            trait_ref,
-            constness: ty::BoundConstness::NotConst,
-            polarity: ty::ImplPolarity::Negative,
-        })
-    }
 }
 
 impl rustc_errors::IntoDiagnosticArg for PolyTraitRef<'_> {
@@ -906,7 +908,7 @@ impl<'tcx> ExistentialTraitRef<'tcx> {
         // otherwise the escaping vars would be captured by the binder
         // debug_assert!(!self_ty.has_escaping_bound_vars());
 
-        ty::TraitRef { def_id: self.def_id, substs: tcx.mk_substs_trait(self_ty, self.substs) }
+        tcx.mk_trait_ref(self.def_id, [self_ty.into()].into_iter().chain(self.substs.iter()))
     }
 }
 
@@ -1282,6 +1284,12 @@ impl<'tcx> ParamTy {
     pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
         tcx.mk_ty_param(self.index, self.name)
     }
+
+    pub fn span_from_generics(&self, tcx: TyCtxt<'tcx>, item_with_generics: DefId) -> Span {
+        let generics = tcx.generics_of(item_with_generics);
+        let type_param = generics.type_param(self, tcx);
+        tcx.def_span(type_param.def_id)
+    }
 }
 
 #[derive(Copy, Clone, Hash, TyEncodable, TyDecodable, Eq, PartialEq, Ord, PartialOrd)]
@@ -1603,7 +1611,7 @@ impl<'tcx> Region<'tcx> {
 impl<'tcx> Ty<'tcx> {
     #[inline(always)]
     pub fn kind(self) -> &'tcx TyKind<'tcx> {
-        &self.0.0.kind
+        &self.0.0
     }
 
     #[inline(always)]
@@ -2095,7 +2103,7 @@ impl<'tcx> Ty<'tcx> {
 
             ty::Str | ty::Slice(_) => (tcx.types.usize, false),
             ty::Dynamic(..) => {
-                let dyn_metadata = tcx.lang_items().dyn_metadata().unwrap();
+                let dyn_metadata = tcx.require_lang_item(LangItem::DynMetadata, None);
                 (tcx.bound_type_of(dyn_metadata).subst(tcx, &[tail.into()]), false)
             },
 
@@ -2117,8 +2125,7 @@ impl<'tcx> Ty<'tcx> {
     /// parameter. This is kind of a phantom type, except that the
     /// most convenient thing for us to are the integral types. This
     /// function converts such a special type into the closure
-    /// kind. To go the other way, use
-    /// `tcx.closure_kind_ty(closure_kind)`.
+    /// kind. To go the other way, use `closure_kind.to_ty(tcx)`.
     ///
     /// Note that during type checking, we use an inference variable
     /// to represent the closure kind, because it has not yet been
@@ -2244,7 +2251,7 @@ impl<'tcx> Ty<'tcx> {
         }
     }
 
-    // If `self` is a primitive, return its [`Symbol`].
+    /// If `self` is a primitive, return its [`Symbol`].
     pub fn primitive_symbol(self) -> Option<Symbol> {
         match self.kind() {
             ty::Bool => Some(sym::bool),