Rollup merge of #65100 - csmoe:generator, r=nikomatsakis

Replace GeneratorSubsts with SubstsRef

Closes #42340
r? @nikomatsakis

Author: tmandry

src/librustc/infer/opaque_types/mod.rs

@@ -733,12 +733,12 @@ where
                 // Skip lifetime parameters of the enclosing item(s)
                 // Also skip the witness type, because that has no free regions.
 
-                for upvar_ty in substs.upvar_tys(def_id, self.tcx) {
+                for upvar_ty in substs.as_generator().upvar_tys(def_id, self.tcx) {
                     upvar_ty.visit_with(self);
                 }
 
-                substs.return_ty(def_id, self.tcx).visit_with(self);
-                substs.yield_ty(def_id, self.tcx).visit_with(self);
+                substs.as_generator().return_ty(def_id, self.tcx).visit_with(self);
+                substs.as_generator().yield_ty(def_id, self.tcx).visit_with(self);
             }
             _ => {
                 ty.super_visit_with(self);
@@ -902,7 +902,7 @@ impl TypeFolder<'tcx> for ReverseMapper<'tcx> {
             ty::Generator(def_id, substs, movability) => {
                 let generics = self.tcx.generics_of(def_id);
                 let substs =
-                    self.tcx.mk_substs(substs.substs.iter().enumerate().map(|(index, &kind)| {
+                    self.tcx.mk_substs(substs.iter().enumerate().map(|(index, &kind)| {
                         if index < generics.parent_count {
                             // Accommodate missing regions in the parent kinds...
                             self.fold_kind_mapping_missing_regions_to_empty(kind)
@@ -912,7 +912,7 @@ impl TypeFolder<'tcx> for ReverseMapper<'tcx> {
                         }
                     }));
 
-                self.tcx.mk_generator(def_id, ty::GeneratorSubsts { substs }, movability)
+                self.tcx.mk_generator(def_id, substs, movability)
             }
 
             ty::Param(..) => {

src/librustc/mir/mod.rs

@@ -15,7 +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, GeneratorSubsts, Region, Ty, TyCtxt,
+    self, AdtDef, CanonicalUserTypeAnnotations, Region, Ty, TyCtxt,
     UserTypeAnnotationIndex,
 };
 
@@ -2189,7 +2189,7 @@ pub enum AggregateKind<'tcx> {
     Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
 
     Closure(DefId, SubstsRef<'tcx>),
-    Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
+    Generator(DefId, SubstsRef<'tcx>, hir::GeneratorMovability),
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]

src/librustc/mir/tcx.rs

@@ -197,7 +197,7 @@ impl<'tcx> Rvalue<'tcx> {
                 let ty = place.ty(local_decls, tcx).ty;
                 match ty.kind {
                     ty::Adt(adt_def, _) => adt_def.repr.discr_type().to_ty(tcx),
-                    ty::Generator(_, substs, _) => substs.discr_ty(tcx),
+                    ty::Generator(_, substs, _) => substs.as_generator().discr_ty(tcx),
                     _ => {
                         // This can only be `0`, for now, so `u8` will suffice.
                         tcx.types.u8

src/librustc/mir/visit.rs

@@ -1,5 +1,5 @@
 use crate::ty::subst::SubstsRef;
-use crate::ty::{CanonicalUserTypeAnnotation, GeneratorSubsts, Ty};
+use crate::ty::{CanonicalUserTypeAnnotation, Ty};
 use crate::mir::*;
 use syntax_pos::Span;
 
@@ -230,12 +230,6 @@ macro_rules! make_mir_visitor {
                 self.super_substs(substs);
             }
 
-            fn visit_generator_substs(&mut self,
-                                      substs: & $($mutability)? GeneratorSubsts<'tcx>,
-                                    _: Location) {
-                self.super_generator_substs(substs);
-            }
-
             fn visit_local_decl(&mut self,
                                 local: Local,
                                 local_decl: & $($mutability)? LocalDecl<'tcx>) {
@@ -628,7 +622,7 @@ macro_rules! make_mir_visitor {
                                 generator_substs,
                                 _movability,
                             ) => {
-                                self.visit_generator_substs(generator_substs, location);
+                                self.visit_substs(generator_substs, location);
                             }
                         }
 
@@ -846,10 +840,6 @@ macro_rules! make_mir_visitor {
             fn super_substs(&mut self, _substs: & $($mutability)? SubstsRef<'tcx>) {
             }
 
-            fn super_generator_substs(&mut self,
-                                      _substs: & $($mutability)? GeneratorSubsts<'tcx>) {
-            }
-
             // Convenience methods
 
             fn visit_location(&mut self, body: & $($mutability)? Body<'tcx>, location: Location) {

src/librustc/traits/mod.rs

@@ -610,7 +610,7 @@ pub struct VtableImplData<'tcx, N> {
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
 pub struct VtableGeneratorData<'tcx, N> {
     pub generator_def_id: DefId,
-    pub substs: ty::GeneratorSubsts<'tcx>,
+    pub substs: SubstsRef<'tcx>,
     /// Nested obligations. This can be non-empty if the generator
     /// signature contains associated types.
     pub nested: Vec<N>

src/librustc/traits/project.rs

@@ -1259,7 +1259,7 @@ fn confirm_generator_candidate<'cx, 'tcx>(
     obligation: &ProjectionTyObligation<'tcx>,
     vtable: VtableGeneratorData<'tcx, PredicateObligation<'tcx>>,
 ) -> Progress<'tcx> {
-    let gen_sig = vtable.substs.poly_sig(vtable.generator_def_id, selcx.tcx());
+    let gen_sig = vtable.substs.as_generator().poly_sig(vtable.generator_def_id, selcx.tcx());
     let Normalized {
         value: gen_sig,
         obligations

src/librustc/traits/select.rs

@@ -2761,8 +2761,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 .collect(),
 
             ty::Generator(def_id, ref substs, _) => {
-                let witness = substs.witness(def_id, self.tcx());
+                let witness = substs.as_generator().witness(def_id, self.tcx());
                 substs
+                    .as_generator()
                     .upvar_tys(def_id, self.tcx())
                     .chain(iter::once(witness))
                     .collect()
@@ -3324,8 +3325,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         )?);
 
         Ok(VtableGeneratorData {
-            generator_def_id: generator_def_id,
-            substs: substs.clone(),
+            generator_def_id,
+            substs,
             nested: obligations,
         })
     }
@@ -3911,9 +3912,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         &mut self,
         obligation: &TraitObligation<'tcx>,
         closure_def_id: DefId,
-        substs: ty::GeneratorSubsts<'tcx>,
+        substs: SubstsRef<'tcx>,
     ) -> ty::PolyTraitRef<'tcx> {
-        let gen_sig = substs.poly_sig(closure_def_id, self.tcx());
+        let gen_sig = substs.as_generator().poly_sig(closure_def_id, self.tcx());
 
         // (1) Feels icky to skip the binder here, but OTOH we know
         // that the self-type is an generator type and hence is

src/librustc/ty/context.rs

@@ -29,7 +29,7 @@ use crate::traits;
 use crate::traits::{Clause, Clauses, GoalKind, Goal, Goals};
 use crate::ty::{self, DefIdTree, Ty, TypeAndMut};
 use crate::ty::{TyS, TyKind, List};
-use crate::ty::{AdtKind, AdtDef, GeneratorSubsts, Region, Const};
+use crate::ty::{AdtKind, AdtDef, Region, Const};
 use crate::ty::{PolyFnSig, InferTy, ParamTy, ProjectionTy, ExistentialPredicate, Predicate};
 use crate::ty::RegionKind;
 use crate::ty::{TyVar, TyVid, IntVar, IntVid, FloatVar, FloatVid, ConstVid};
@@ -2510,7 +2510,7 @@ impl<'tcx> TyCtxt<'tcx> {
     #[inline]
     pub fn mk_generator(self,
                         id: DefId,
-                        generator_substs: GeneratorSubsts<'tcx>,
+                        generator_substs: SubstsRef<'tcx>,
                         movability: hir::GeneratorMovability)
                         -> Ty<'tcx> {
         self.mk_ty(Generator(id, generator_substs, movability))

src/librustc/ty/flags.rs

@@ -94,7 +94,7 @@ impl FlagComputation {
             &ty::Generator(_, ref substs, _) => {
                 self.add_flags(TypeFlags::HAS_TY_CLOSURE);
                 self.add_flags(TypeFlags::HAS_FREE_LOCAL_NAMES);
-                self.add_substs(&substs.substs);
+                self.add_substs(substs);
             }
 
             &ty::GeneratorWitness(ref ts) => {

src/librustc/ty/instance.rs

@@ -71,7 +71,7 @@ impl<'tcx> Instance<'tcx> {
                 ))
             }
             ty::Generator(def_id, substs, _) => {
-                let sig = substs.poly_sig(def_id, tcx);
+                let sig = substs.as_generator().poly_sig(def_id, tcx);
 
                 let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
                 let env_ty = tcx.mk_mut_ref(tcx.mk_region(env_region), ty);
@@ -395,7 +395,7 @@ fn resolve_associated_item<'tcx>(
         traits::VtableGenerator(generator_data) => {
             Some(Instance {
                 def: ty::InstanceDef::Item(generator_data.generator_def_id),
-                substs: generator_data.substs.substs
+                substs: generator_data.substs
             })
         }
         traits::VtableClosure(closure_data) => {