Rollup merge of rust-lang#64817 - csmoe:closure, r=nikomatsakis

Replace ClosureSubsts with SubstsRef

Addresses rust-lang#42340 part 3
rust-lang#59312 might benefit from this clean up.
r? @nikomatsakis

src/librustc/infer/error_reporting/need_type_info.rs

@@ -220,7 +220,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
         let ty_msg = match local_visitor.found_ty {
             Some(ty::TyS { kind: ty::Closure(def_id, substs), .. }) => {
-                let fn_sig = substs.closure_sig(*def_id, self.tcx);
+                let fn_sig = substs.as_closure().sig(*def_id, self.tcx);
                 let args = closure_args(&fn_sig);
                 let ret = fn_sig.output().skip_binder().to_string();
                 format!(" for the closure `fn({}) -> {}`", args, ret)
@@ -255,7 +255,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
         let suffix = match local_visitor.found_ty {
             Some(ty::TyS { kind: ty::Closure(def_id, substs), .. }) => {
-                let fn_sig = substs.closure_sig(*def_id, self.tcx);
+                let fn_sig = substs.as_closure().sig(*def_id, self.tcx);
                 let ret = fn_sig.output().skip_binder().to_string();
 
                 if let Some(ExprKind::Closure(_, decl, body_id, ..)) = local_visitor.found_closure {

src/librustc/infer/mod.rs

@@ -1504,9 +1504,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn closure_kind(
         &self,
         closure_def_id: DefId,
-        closure_substs: ty::ClosureSubsts<'tcx>,
+        closure_substs: SubstsRef<'tcx>,
     ) -> Option<ty::ClosureKind> {
-        let closure_kind_ty = closure_substs.closure_kind_ty(closure_def_id, self.tcx);
+        let closure_kind_ty = closure_substs.as_closure().kind_ty(closure_def_id, self.tcx);
         let closure_kind_ty = self.shallow_resolve(closure_kind_ty);
         closure_kind_ty.to_opt_closure_kind()
     }
@@ -1518,9 +1518,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn closure_sig(
         &self,
         def_id: DefId,
-        substs: ty::ClosureSubsts<'tcx>,
+        substs: SubstsRef<'tcx>,
     ) -> ty::PolyFnSig<'tcx> {
-        let closure_sig_ty = substs.closure_sig_ty(def_id, self.tcx);
+        let closure_sig_ty = substs.as_closure().sig_ty(def_id, self.tcx);
         let closure_sig_ty = self.shallow_resolve(closure_sig_ty);
         closure_sig_ty.fn_sig(self.tcx)
     }

src/librustc/infer/opaque_types/mod.rs

@@ -722,11 +722,11 @@ where
             ty::Closure(def_id, ref substs) => {
                 // Skip lifetime parameters of the enclosing item(s)
 
-                for upvar_ty in substs.upvar_tys(def_id, self.tcx) {
+                for upvar_ty in substs.as_closure().upvar_tys(def_id, self.tcx) {
                     upvar_ty.visit_with(self);
                 }
 
-                substs.closure_sig_ty(def_id, self.tcx).visit_with(self);
+                substs.as_closure().sig_ty(def_id, self.tcx).visit_with(self);
             }
 
             ty::Generator(def_id, ref substs, _) => {
@@ -886,7 +886,7 @@ impl TypeFolder<'tcx> for ReverseMapper<'tcx> {
 
                 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)
@@ -896,7 +896,7 @@ impl TypeFolder<'tcx> for ReverseMapper<'tcx> {
                         }
                     }));
 
-                self.tcx.mk_closure(def_id, ty::ClosureSubsts { substs })
+                self.tcx.mk_closure(def_id, substs)
             }
 
             ty::Generator(def_id, substs, movability) => {

src/librustc/middle/mem_categorization.rs

@@ -740,16 +740,18 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         let ty = self.node_ty(fn_hir_id)?;
         let kind = match ty.kind {
             ty::Generator(..) => ty::ClosureKind::FnOnce,
-            ty::Closure(closure_def_id, closure_substs) => {
+            ty::Closure(closure_def_id, substs) => {
                 match self.infcx {
                     // During upvar inference we may not know the
                     // closure kind, just use the LATTICE_BOTTOM value.
                     Some(infcx) =>
-                        infcx.closure_kind(closure_def_id, closure_substs)
-                             .unwrap_or(ty::ClosureKind::LATTICE_BOTTOM),
+                        infcx.closure_kind(
+                            closure_def_id,
+                            substs
+                        ).unwrap_or(ty::ClosureKind::LATTICE_BOTTOM),
 
                     None =>
-                        closure_substs.closure_kind(closure_def_id, self.tcx),
+                        substs.as_closure().kind(closure_def_id, self.tcx),
                 }
             }
             _ => span_bug!(span, "unexpected type for fn in mem_categorization: {:?}", ty),

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, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt,
+    self, AdtDef, CanonicalUserTypeAnnotations, GeneratorSubsts, Region, Ty, TyCtxt,
     UserTypeAnnotationIndex,
 };
 
@@ -2188,7 +2188,7 @@ pub enum AggregateKind<'tcx> {
     /// active field index would identity the field `c`
     Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
 
-    Closure(DefId, ClosureSubsts<'tcx>),
+    Closure(DefId, SubstsRef<'tcx>),
     Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
 }
 

src/librustc/mir/visit.rs

@@ -1,5 +1,5 @@
 use crate::ty::subst::SubstsRef;
-use crate::ty::{CanonicalUserTypeAnnotation, ClosureSubsts, GeneratorSubsts, Ty};
+use crate::ty::{CanonicalUserTypeAnnotation, GeneratorSubsts, Ty};
 use crate::mir::*;
 use syntax_pos::Span;
 
@@ -230,12 +230,6 @@ macro_rules! make_mir_visitor {
                 self.super_substs(substs);
             }
 
-            fn visit_closure_substs(&mut self,
-                                    substs: & $($mutability)? ClosureSubsts<'tcx>,
-                                    _: Location) {
-                self.super_closure_substs(substs);
-            }
-
             fn visit_generator_substs(&mut self,
                                       substs: & $($mutability)? GeneratorSubsts<'tcx>,
                                     _: Location) {
@@ -627,7 +621,7 @@ macro_rules! make_mir_visitor {
                                 _,
                                 closure_substs
                             ) => {
-                                self.visit_closure_substs(closure_substs, location);
+                                self.visit_substs(closure_substs, location);
                             }
                             AggregateKind::Generator(
                                 _,
@@ -856,10 +850,6 @@ macro_rules! make_mir_visitor {
                                       _substs: & $($mutability)? GeneratorSubsts<'tcx>) {
             }
 
-            fn super_closure_substs(&mut self,
-                                    _substs: & $($mutability)? ClosureSubsts<'tcx>) {
-            }
-
             // Convenience methods
 
             fn visit_location(&mut self, body: & $($mutability)? Body<'tcx>, location: Location) {

src/librustc/traits/mod.rs

@@ -619,7 +619,7 @@ pub struct VtableGeneratorData<'tcx, N> {
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
 pub struct VtableClosureData<'tcx, N> {
     pub closure_def_id: DefId,
-    pub substs: ty::ClosureSubsts<'tcx>,
+    pub substs: SubstsRef<'tcx>,
     /// Nested obligations. This can be non-empty if the closure
     /// signature contains associated types.
     pub nested: Vec<N>

src/librustc/traits/project.rs

@@ -1334,7 +1334,8 @@ fn confirm_closure_candidate<'cx, 'tcx>(
 ) -> Progress<'tcx> {
     let tcx = selcx.tcx();
     let infcx = selcx.infcx();
-    let closure_sig_ty = vtable.substs.closure_sig_ty(vtable.closure_def_id, tcx);
+    let closure_sig_ty = vtable.substs
+        .as_closure().sig_ty(vtable.closure_def_id, tcx);
     let closure_sig = infcx.shallow_resolve(closure_sig_ty).fn_sig(tcx);
     let Normalized {
         value: closure_sig,

src/librustc/traits/query/dropck_outlives.rs

@@ -213,6 +213,7 @@ pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
         // check if *any* of those are trivial.
         ty::Tuple(ref tys) => tys.iter().all(|t| trivial_dropck_outlives(tcx, t.expect_ty())),
         ty::Closure(def_id, ref substs) => substs
+            .as_closure()
             .upvar_tys(def_id, tcx)
             .all(|t| trivial_dropck_outlives(tcx, t)),
 

src/librustc/traits/select.rs

@@ -2051,7 +2051,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     "assemble_unboxed_candidates: kind={:?} obligation={:?}",
                     kind, obligation
                 );
-                match self.infcx.closure_kind(closure_def_id, closure_substs) {
+                match self.infcx.closure_kind(
+                    closure_def_id,
+                    closure_substs
+                ) {
                     Some(closure_kind) => {
                         debug!(
                             "assemble_unboxed_candidates: closure_kind = {:?}",
@@ -2669,7 +2672,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             ty::Closure(def_id, substs) => {
                 // (*) binder moved here
                 Where(ty::Binder::bind(
-                    substs.upvar_tys(def_id, self.tcx()).collect(),
+                    substs.as_closure().upvar_tys(def_id, self.tcx()).collect(),
                 ))
             }
 
@@ -2753,7 +2756,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 tys.iter().map(|k| k.expect_ty()).collect()
             }
 
-            ty::Closure(def_id, ref substs) => substs.upvar_tys(def_id, self.tcx()).collect(),
+            ty::Closure(def_id, ref substs) => substs.as_closure()
+                .upvar_tys(def_id, self.tcx())
+                .collect(),
 
             ty::Generator(def_id, ref substs, _) => {
                 let witness = substs.witness(def_id, self.tcx());
@@ -3370,17 +3375,22 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         )?);
 
         // FIXME: chalk
+
         if !self.tcx().sess.opts.debugging_opts.chalk {
             obligations.push(Obligation::new(
                 obligation.cause.clone(),
                 obligation.param_env,
-                ty::Predicate::ClosureKind(closure_def_id, substs, kind),
+                ty::Predicate::ClosureKind(
+                    closure_def_id,
+                    substs,
+                    kind
+                ),
             ));
         }
 
         Ok(VtableClosureData {
             closure_def_id,
-            substs: substs.clone(),
+            substs: substs,
             nested: obligations,
         })
     }
@@ -3869,7 +3879,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         &mut self,
         obligation: &TraitObligation<'tcx>,
         closure_def_id: DefId,
-        substs: ty::ClosureSubsts<'tcx>,
+        substs: SubstsRef<'tcx>,
     ) -> ty::PolyTraitRef<'tcx> {
         debug!(
             "closure_trait_ref_unnormalized(obligation={:?}, closure_def_id={:?}, substs={:?})",

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, ClosureSubsts, GeneratorSubsts, Region, Const};
+use crate::ty::{AdtKind, AdtDef, GeneratorSubsts, 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};
@@ -2502,7 +2502,7 @@ impl<'tcx> TyCtxt<'tcx> {
         }
 
     #[inline]
-    pub fn mk_closure(self, closure_id: DefId, closure_substs: ClosureSubsts<'tcx>)
+    pub fn mk_closure(self, closure_id: DefId, closure_substs: SubstsRef<'tcx>)
                       -> Ty<'tcx> {
         self.mk_ty(Closure(closure_id, closure_substs))
     }

src/librustc/ty/flags.rs

@@ -106,7 +106,7 @@ impl FlagComputation {
             &ty::Closure(_, 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::Bound(debruijn, _) => {

src/librustc/ty/instance.rs

@@ -59,7 +59,7 @@ impl<'tcx> Instance<'tcx> {
             // Shims currently have type FnPtr. Not sure this should remain.
             ty::FnPtr(_) => ty.fn_sig(tcx),
             ty::Closure(def_id, substs) => {
-                let sig = substs.closure_sig(def_id, tcx);
+                let sig = substs.as_closure().sig(def_id, tcx);
 
                 let env_ty = tcx.closure_env_ty(def_id, substs).unwrap();
                 sig.map_bound(|sig| tcx.mk_fn_sig(
@@ -315,14 +315,14 @@ impl<'tcx> Instance<'tcx> {
     pub fn resolve_closure(
         tcx: TyCtxt<'tcx>,
         def_id: DefId,
-        substs: ty::ClosureSubsts<'tcx>,
+        substs: ty::SubstsRef<'tcx>,
         requested_kind: ty::ClosureKind,
     ) -> Instance<'tcx> {
-        let actual_kind = substs.closure_kind(def_id, tcx);
+        let actual_kind = substs.as_closure().kind(def_id, tcx);
 
         match needs_fn_once_adapter_shim(actual_kind, requested_kind) {
             Ok(true) => Instance::fn_once_adapter_instance(tcx, def_id, substs),
-            _ => Instance::new(def_id, substs.substs)
+            _ => Instance::new(def_id, substs)
         }
     }
 
@@ -335,7 +335,7 @@ impl<'tcx> Instance<'tcx> {
     pub fn fn_once_adapter_instance(
         tcx: TyCtxt<'tcx>,
         closure_did: DefId,
-        substs: ty::ClosureSubsts<'tcx>,
+        substs: ty::SubstsRef<'tcx>,
     ) -> Instance<'tcx> {
         debug!("fn_once_adapter_shim({:?}, {:?})",
                closure_did,
@@ -348,7 +348,7 @@ impl<'tcx> Instance<'tcx> {
 
         let self_ty = tcx.mk_closure(closure_did, substs);
 
-        let sig = substs.closure_sig(closure_did, tcx);
+        let sig = substs.as_closure().sig(closure_did, tcx);
         let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
         assert_eq!(sig.inputs().len(), 1);
         let substs = tcx.mk_substs_trait(self_ty, &[sig.inputs()[0].into()]);

src/librustc/ty/layout.rs

@@ -674,7 +674,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
             ty::Generator(def_id, substs, _) => self.generator_layout(ty, def_id, &substs)?,
 
             ty::Closure(def_id, ref substs) => {
-                let tys = substs.upvar_tys(def_id, tcx);
+                let tys = substs.as_closure().upvar_tys(def_id, tcx);
                 univariant(&tys.map(|ty| self.layout_of(ty)).collect::<Result<Vec<_>, _>>()?,
                     &ReprOptions::default(),
                     StructKind::AlwaysSized)?
@@ -2147,7 +2147,7 @@ where
 
             // Tuples, generators and closures.
             ty::Closure(def_id, ref substs) => {
-                substs.upvar_tys(def_id, tcx).nth(i).unwrap()
+                substs.as_closure().upvar_tys(def_id, tcx).nth(i).unwrap()
             }
 
             ty::Generator(def_id, ref substs, _) => {

src/librustc/ty/mod.rs

@@ -1111,7 +1111,7 @@ pub enum Predicate<'tcx> {
     /// No direct syntax. May be thought of as `where T: FnFoo<...>`
     /// for some substitutions `...` and `T` being a closure type.
     /// Satisfied (or refuted) once we know the closure's kind.
-    ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
+    ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
 
     /// `T1 <: T2`
     Subtype(PolySubtypePredicate<'tcx>),
@@ -1458,7 +1458,7 @@ impl<'tcx> Predicate<'tcx> {
                 WalkTysIter::None
             }
             ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
-                WalkTysIter::Types(closure_substs.substs.types())
+                WalkTysIter::Types(closure_substs.types())
             }
             ty::Predicate::ConstEvaluatable(_, substs) => {
                 WalkTysIter::Types(substs.types())

src/librustc/ty/outlives.rs

@@ -62,7 +62,7 @@ impl<'tcx> TyCtxt<'tcx> {
         // projection).
         match ty.kind {
             ty::Closure(def_id, ref substs) => {
-                for upvar_ty in substs.upvar_tys(def_id, *self) {
+                for upvar_ty in substs.as_closure().upvar_tys(def_id, *self) {
                     self.compute_components(upvar_ty, out);
                 }
             }

src/librustc/ty/print/obsolete.rs

@@ -8,7 +8,7 @@
 use rustc::hir::def_id::DefId;
 use rustc::mir::interpret::ConstValue;
 use rustc::ty::subst::SubstsRef;
-use rustc::ty::{self, ClosureSubsts, Const, GeneratorSubsts, Instance, Ty, TyCtxt};
+use rustc::ty::{self, Const, GeneratorSubsts, Instance, Ty, TyCtxt};
 use rustc::{bug, hir};
 use std::fmt::Write;
 use std::iter;
@@ -154,8 +154,8 @@ impl DefPathBasedNames<'tcx> {
                     self.push_type_name(sig.output(), output, debug);
                 }
             }
-            ty::Generator(def_id, GeneratorSubsts { ref substs }, _)
-            | ty::Closure(def_id, ClosureSubsts { ref substs }) => {
+            ty::Generator(def_id, GeneratorSubsts { substs }, _)
+            | ty::Closure(def_id, substs) => {
                 self.push_def_path(def_id, output);
                 let generics = self.tcx.generics_of(self.tcx.closure_base_def_id(def_id));
                 let substs = substs.truncate_to(self.tcx, generics);