rustc: move closure upvar types to the closure substs

This moves closures to the (DefId, Substs) scheme like all other items,
and saves a word from the size of TyS now that Substs is 2 words.

src/librustc/infer/mod.rs

@@ -1657,7 +1657,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     {
         if let InferTables::Local(tables) = self.tables {
             if let Some(ty) = tables.borrow().closure_tys.get(&def_id) {
-                return ty.subst(self.tcx, substs.func_substs);
+                return ty.subst(self.tcx, substs.substs);
             }
         }
 

src/librustc/lib.rs

@@ -40,6 +40,7 @@
 #![feature(rustc_private)]
 #![feature(slice_patterns)]
 #![feature(staged_api)]
+#![feature(unboxed_closures)]
 #![cfg_attr(stage0, feature(question_mark))]
 #![cfg_attr(test, feature(test))]
 

src/librustc/traits/select.rs

@@ -1912,16 +1912,16 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 tys.to_vec()
             }
 
-            ty::TyClosure(_, ref substs) => {
+            ty::TyClosure(def_id, ref substs) => {
                 // FIXME(#27086). We are invariant w/r/t our
-                // substs.func_substs, but we don't see them as
+                // func_substs, but we don't see them as
                 // constituent types; this seems RIGHT but also like
                 // something that a normal type couldn't simulate. Is
                 // this just a gap with the way that PhantomData and
                 // OIBIT interact? That is, there is no way to say
                 // "make me invariant with respect to this TYPE, but
                 // do not act as though I can reach it"
-                substs.upvar_tys.to_vec()
+                substs.upvar_tys(def_id, self.tcx()).collect()
             }
 
             // for `PhantomData<T>`, we pass `T`

src/librustc/ty/contents.rs

@@ -98,10 +98,11 @@ impl TypeContents {
         TC::OwnsOwned | (*self & TC::OwnsAll)
     }
 
-    pub fn union<T, F>(v: &[T], mut f: F) -> TypeContents where
-        F: FnMut(&T) -> TypeContents,
+    pub fn union<I, T, F>(v: I, mut f: F) -> TypeContents where
+        I: IntoIterator<Item=T>,
+        F: FnMut(T) -> TypeContents,
     {
-        v.iter().fold(TC::None, |tc, ty| tc | f(ty))
+        v.into_iter().fold(TC::None, |tc, ty| tc | f(ty))
     }
 
     pub fn has_dtor(&self) -> bool {
@@ -215,8 +216,10 @@ impl<'a, 'tcx> ty::TyS<'tcx> {
                 }
                 ty::TyStr => TC::None,
 
-                ty::TyClosure(_, ref substs) => {
-                    TypeContents::union(&substs.upvar_tys, |ty| tc_ty(tcx, &ty, cache))
+                ty::TyClosure(def_id, ref substs) => {
+                    TypeContents::union(
+                        substs.upvar_tys(def_id, tcx),
+                        |ty| tc_ty(tcx, &ty, cache))
                 }
 
                 ty::TyTuple(ref tys) => {

src/librustc/ty/context.rs

@@ -1446,12 +1446,10 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     pub fn mk_closure(self,
                       closure_id: DefId,
-                      substs: &'tcx Substs<'tcx>,
-                      tys: &[Ty<'tcx>])
+                      substs: &'tcx Substs<'tcx>)
                       -> Ty<'tcx> {
         self.mk_closure_from_closure_substs(closure_id, ClosureSubsts {
-            func_substs: substs,
-            upvar_tys: self.intern_type_list(tys)
+            substs: substs
         })
     }
 
@@ -1574,4 +1572,3 @@ impl<T, R, E> InternIteratorElement<T, R> for Result<T, E> {
         Ok(f(&iter.collect::<Result<AccumulateVec<[_; 8]>, _>>()?))
     }
 }
-

src/librustc/ty/flags.rs

@@ -88,8 +88,7 @@ impl FlagComputation {
             &ty::TyClosure(_, ref substs) => {
                 self.add_flags(TypeFlags::HAS_TY_CLOSURE);
                 self.add_flags(TypeFlags::HAS_LOCAL_NAMES);
-                self.add_substs(&substs.func_substs);
-                self.add_tys(&substs.upvar_tys);
+                self.add_substs(&substs.substs);
             }
 
             &ty::TyInfer(infer) => {

src/librustc/ty/layout.rs

@@ -631,7 +631,9 @@ impl<'a, 'gcx, 'tcx> Struct {
 
             // Perhaps one of the upvars of this closure is non-zero
             // Let's recurse and find out!
-            (_, &ty::TyClosure(_, ty::ClosureSubsts { upvar_tys: tys, .. })) |
+            (_, &ty::TyClosure(def_id, ref substs)) => {
+                Struct::non_zero_field_path(infcx, substs.upvar_tys(def_id, tcx))
+            }
             // Can we use one of the fields in this tuple?
             (_, &ty::TyTuple(tys)) => {
                 Struct::non_zero_field_path(infcx, tys.iter().cloned())
@@ -961,7 +963,13 @@ impl<'a, 'gcx, 'tcx> Layout {
             }
 
             // Tuples and closures.
-            ty::TyClosure(_, ty::ClosureSubsts { upvar_tys: tys, .. }) |
+            ty::TyClosure(def_id, ref substs) => {
+                let mut st = Struct::new(dl, false);
+                let tys = substs.upvar_tys(def_id, tcx);
+                st.extend(dl, tys.map(|ty| ty.layout(infcx)), ty)?;
+                Univariant { variant: st, non_zero: false }
+            }
+
             ty::TyTuple(tys) => {
                 let mut st = Struct::new(dl, false);
                 st.extend(dl, tys.iter().map(|ty| ty.layout(infcx)), ty)?;

src/librustc/ty/mod.rs

@@ -2544,12 +2544,12 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // tables by typeck; else, it will be retreived from
         // the external crate metadata.
         if let Some(ty) = self.tables.borrow().closure_tys.get(&def_id) {
-            return ty.subst(self, substs.func_substs);
+            return ty.subst(self, substs.substs);
         }
 
         let ty = self.sess.cstore.closure_ty(self.global_tcx(), def_id);
         self.tables.borrow_mut().closure_tys.insert(def_id, ty.clone());
-        ty.subst(self, substs.func_substs)
+        ty.subst(self, substs.substs)
     }
 
     /// Given the def_id of an impl, return the def_id of the trait it implements.

src/librustc/ty/outlives.rs

@@ -72,7 +72,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // in the `subtys` iterator (e.g., when encountering a
         // projection).
         match ty.sty {
-            ty::TyClosure(_, ref substs) => {
+            ty::TyClosure(def_id, ref substs) => {
                 // FIXME(#27086). We do not accumulate from substs, since they
                 // don't represent reachable data. This means that, in
                 // practice, some of the lifetime parameters might not
@@ -110,7 +110,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 // what func/type parameters are used and unused,
                 // taking into consideration UFCS and so forth.
 
-                for &upvar_ty in substs.upvar_tys {
+                for upvar_ty in substs.upvar_tys(def_id, *self) {
                     self.compute_components(upvar_ty, out);
                 }
             }

src/librustc/ty/relate.rs

@@ -534,13 +534,8 @@ impl<'tcx> Relate<'tcx> for ty::ClosureSubsts<'tcx> {
                            -> RelateResult<'tcx, ty::ClosureSubsts<'tcx>>
         where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
     {
-        let substs = relate_substs(relation, None, a.func_substs, b.func_substs)?;
-        assert_eq!(a.upvar_tys.len(), b.upvar_tys.len());
-        Ok(ty::ClosureSubsts {
-            func_substs: substs,
-            upvar_tys: relation.tcx().mk_type_list(
-                a.upvar_tys.iter().zip(b.upvar_tys).map(|(a, b)| relation.relate(a, b)))?
-        })
+        let substs = relate_substs(relation, None, a.substs, b.substs)?;
+        Ok(ty::ClosureSubsts { substs: substs })
     }
 }
 

src/librustc/ty/structural_impls.rs

@@ -198,11 +198,8 @@ impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::Binder<T> {
 impl<'a, 'tcx> Lift<'tcx> for ty::ClosureSubsts<'a> {
     type Lifted = ty::ClosureSubsts<'tcx>;
     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(&(self.func_substs, self.upvar_tys)).map(|(substs, upvar_tys)| {
-            ty::ClosureSubsts {
-                func_substs: substs,
-                upvar_tys: upvar_tys
-            }
+        tcx.lift(&self.substs).map(|substs| {
+            ty::ClosureSubsts { substs: substs }
         })
     }
 }
@@ -654,13 +651,12 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Region {
 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureSubsts<'tcx> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
         ty::ClosureSubsts {
-            func_substs: self.func_substs.fold_with(folder),
-            upvar_tys: self.upvar_tys.fold_with(folder),
+            substs: self.substs.fold_with(folder),
         }
     }
 
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        self.func_substs.visit_with(visitor) || self.upvar_tys.visit_with(visitor)
+        self.substs.visit_with(visitor)
     }
 }
 

src/librustc/ty/sty.rs

@@ -11,6 +11,7 @@
 //! This module contains TypeVariants and its major components
 
 use hir::def_id::DefId;
+
 use middle::region;
 use ty::subst::Substs;
 use ty::{self, AdtDef, ToPredicate, TypeFlags, Ty, TyCtxt, TypeFoldable};
@@ -254,15 +255,23 @@ pub enum TypeVariants<'tcx> {
 /// handle). Plus it fixes an ICE. :P
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
 pub struct ClosureSubsts<'tcx> {
-    /// Lifetime and type parameters from the enclosing function.
+    /// Lifetime and type parameters from the enclosing function,
+    /// concatenated with the types of the upvars.
+    ///
     /// These are separated out because trans wants to pass them around
     /// when monomorphizing.
-    pub func_substs: &'tcx Substs<'tcx>,
+    pub substs: &'tcx Substs<'tcx>,
+}
 
-    /// The types of the upvars. The list parallels the freevars and
-    /// `upvar_borrows` lists. These are kept distinct so that we can
-    /// easily index into them.
-    pub upvar_tys: &'tcx Slice<Ty<'tcx>>
+impl<'a, 'gcx, 'acx, 'tcx> ClosureSubsts<'tcx> {
+    #[inline]
+    pub fn upvar_tys(self, def_id: DefId, tcx: TyCtxt<'a, 'gcx, 'acx>) ->
+        impl Iterator<Item=Ty<'tcx>> + 'tcx
+    {
+        let generics = tcx.item_generics(def_id);
+        self.substs[self.substs.len()-generics.own_count()..].iter().map(
+            |t| t.as_type().expect("unexpected region in upvars"))
+    }
 }
 
 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
@@ -1234,7 +1243,7 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
                 substs.regions().collect()
             }
             TyClosure(_, ref substs) => {
-                substs.func_substs.regions().collect()
+                substs.substs.regions().collect()
             }
             TyProjection(ref data) => {
                 data.trait_ref.substs.regions().collect()

src/librustc/ty/subst.rs

@@ -274,6 +274,20 @@ impl<'a, 'gcx, 'tcx> Substs<'tcx> {
         let defs = tcx.item_generics(source_ancestor);
         tcx.mk_substs(target_substs.iter().chain(&self[defs.own_count()..]).cloned())
     }
+
+    pub fn extend_with_types(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
+                             types: &[Ty<'tcx>])
+                             -> &'tcx Substs<'tcx> {
+        tcx.mk_substs(
+            self[..].iter().cloned().chain(
+                types.iter().map(|a| Kind::from(*a)))
+        )
+    }
+
+    pub fn truncate_to(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, generics: &ty::Generics<'tcx>)
+                       -> &'tcx Substs<'tcx> {
+        tcx.mk_substs(self.iter().take(generics.count()).cloned())
+    }
 }
 
 impl<'tcx> TypeFoldable<'tcx> for &'tcx Substs<'tcx> {

src/librustc/ty/util.rs

@@ -11,6 +11,7 @@
 //! misc. type-system utilities too small to deserve their own file
 
 use hir::def_id::DefId;
+use hir::map::DefPathData;
 use infer::InferCtxt;
 use hir::map as ast_map;
 use hir::pat_util;
@@ -390,6 +391,16 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // (e.g. calling `foo.0.clone()` of `Foo<T:Clone>`).
         return !self.has_attr(dtor_method, "unsafe_destructor_blind_to_params");
     }
+
+    pub fn closure_base_def_id(&self, def_id: DefId) -> DefId {
+        let mut def_id = def_id;
+        while self.def_key(def_id).disambiguated_data.data == DefPathData::ClosureExpr {
+            def_id = self.parent_def_id(def_id).unwrap_or_else(|| {
+                bug!("closure {:?} has no parent", def_id);
+            });
+        }
+        def_id
+    }
 }
 
 /// When hashing a type this ends up affecting properties like symbol names. We

src/librustc/ty/walk.rs

@@ -97,8 +97,7 @@ fn push_subtypes<'tcx>(stack: &mut Vec<Ty<'tcx>>, parent_ty: Ty<'tcx>) {
             stack.extend(substs.types().rev());
         }
         ty::TyClosure(_, ref substs) => {
-            stack.extend(substs.func_substs.types().rev());
-            stack.extend(substs.upvar_tys.iter().cloned().rev());
+            stack.extend(substs.substs.types().rev());
         }
         ty::TyTuple(ts) => {
             stack.extend(ts.iter().cloned().rev());

src/librustc/util/ppaux.rs

@@ -907,13 +907,14 @@ impl<'tcx> fmt::Display for ty::TypeVariants<'tcx> {
             }
             TyStr => write!(f, "str"),
             TyClosure(did, substs) => ty::tls::with(|tcx| {
+                let upvar_tys = substs.upvar_tys(did, tcx);
                 write!(f, "[closure")?;
 
                 if let Some(node_id) = tcx.map.as_local_node_id(did) {
                     write!(f, "@{:?}", tcx.map.span(node_id))?;
                     let mut sep = " ";
                     tcx.with_freevars(node_id, |freevars| {
-                        for (freevar, upvar_ty) in freevars.iter().zip(substs.upvar_tys) {
+                        for (freevar, upvar_ty) in freevars.iter().zip(upvar_tys) {
                             let def_id = freevar.def.def_id();
                             let node_id = tcx.map.as_local_node_id(def_id).unwrap();
                             write!(f,
@@ -930,7 +931,7 @@ impl<'tcx> fmt::Display for ty::TypeVariants<'tcx> {
                     // visible in trans bug reports, I imagine.
                     write!(f, "@{:?}", did)?;
                     let mut sep = " ";
-                    for (index, upvar_ty) in substs.upvar_tys.iter().enumerate() {
+                    for (index, upvar_ty) in upvar_tys.enumerate() {
                         write!(f, "{}{}:{}", sep, index, upvar_ty)?;
                         sep = ", ";
                     }

src/librustc_borrowck/borrowck/mir/elaborate_drops.rs

@@ -709,9 +709,11 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
             ty::TyAdt(def, substs) => {
                 self.open_drop_for_adt(c, def, substs)
             }
-            ty::TyTuple(tys) | ty::TyClosure(_, ty::ClosureSubsts {
-                upvar_tys: tys, ..
-            }) => {
+            ty::TyClosure(def_id, substs) => {
+                let tys : Vec<_> = substs.upvar_tys(def_id, self.tcx).collect();
+                self.open_drop_for_tuple(c, &tys)
+            }
+            ty::TyTuple(tys) => {
                 self.open_drop_for_tuple(c, tys)
             }
             ty::TyBox(ty) => {

src/librustc_metadata/encoder.rs

@@ -1059,7 +1059,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             ty: None,
             inherent_impls: LazySeq::empty(),
             variances: LazySeq::empty(),
-            generics: None,
+            generics: Some(self.encode_generics(def_id)),
             predicates: None,
 
             ast: None,

src/librustc_mir/hair/cx/expr.rs

@@ -521,8 +521,8 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             };
             let upvars = cx.tcx.with_freevars(expr.id, |freevars| {
                 freevars.iter()
-                    .enumerate()
-                    .map(|(i, fv)| capture_freevar(cx, expr, fv, substs.upvar_tys[i]))
+                    .zip(substs.upvar_tys(def_id, cx.tcx))
+                    .map(|(fv, ty)| capture_freevar(cx, expr, fv, ty))
                     .collect()
             });
             ExprKind::Closure {

src/librustc_mir/transform/type_check.rs

@@ -274,9 +274,15 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
                 ty::TyAdt(adt_def, substs) if adt_def.is_univariant() => {
                         (&adt_def.variants[0], substs)
                     }
-                ty::TyTuple(tys) | ty::TyClosure(_, ty::ClosureSubsts {
-                    upvar_tys: tys, ..
-                }) => {
+                ty::TyClosure(def_id, substs) => {
+                    return match substs.upvar_tys(def_id, tcx).nth(field.index()) {
+                        Some(ty) => Ok(ty),
+                        None => Err(FieldAccessError::OutOfRange {
+                            field_count: substs.upvar_tys(def_id, tcx).count()
+                        })
+                    }
+                }
+                ty::TyTuple(tys) => {
                     return match tys.get(field.index()) {
                         Some(&ty) => Ok(ty),
                         None => Err(FieldAccessError::OutOfRange {

src/librustc_trans/adt.rs

@@ -108,9 +108,9 @@ fn compute_fields<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>,
             }).collect::<Vec<_>>()
         },
         ty::TyTuple(fields) => fields.to_vec(),
-        ty::TyClosure(_, substs) => {
+        ty::TyClosure(def_id, substs) => {
             if variant_index > 0 { bug!("{} is a closure, which only has one variant", t);}
-            substs.upvar_tys.to_vec()
+            substs.upvar_tys(def_id, cx.tcx()).collect()
         },
         _ => bug!("{} is not a type that can have fields.", t)
     }