auto merge of #14869 : nick29581/rust/tstore, r=nmatsakis

Use ty_rptr/ty_uniq(ty_trait) rather than TraitStore to represent trait types.
Also addresses (but doesn't close) #12470.
Part of the work towards DST (#12938).

Author: bors

src/librustc/metadata/tydecode.rs

@@ -346,10 +346,9 @@ fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
         assert_eq!(next(st), '[');
         let def = parse_def(st, NominalType, |x,y| conv(x,y));
         let substs = parse_substs(st, |x,y| conv(x,y));
-        let store = parse_trait_store(st, |x,y| conv(x,y));
         let bounds = parse_bounds(st, |x,y| conv(x,y));
         assert_eq!(next(st), ']');
-        return ty::mk_trait(st.tcx, def, substs, store, bounds.builtin_bounds);
+        return ty::mk_trait(st.tcx, def, substs, bounds.builtin_bounds);
       }
       'p' => {
         let did = parse_def(st, TypeParameter, |x,y| conv(x,y));

src/librustc/metadata/tyencode.rs

@@ -232,12 +232,10 @@ fn enc_sty(w: &mut MemWriter, cx: &ctxt, st: &ty::sty) {
         ty::ty_trait(box ty::TyTrait {
                 def_id,
                 ref substs,
-                store,
                 bounds
             }) => {
             mywrite!(w, "x[{}|", (cx.ds)(def_id));
             enc_substs(w, cx, substs);
-            enc_trait_store(w, cx, store);
             let bounds = ty::ParamBounds {builtin_bounds: bounds,
                                           trait_bounds: Vec::new()};
             enc_bounds(w, cx, &bounds);

src/librustc/middle/kind.rs

@@ -361,9 +361,12 @@ fn check_bounds_on_type_parameters(cx: &mut Context, e: &Expr) {
 fn check_trait_cast(cx: &mut Context, source_ty: ty::t, target_ty: ty::t, span: Span) {
     check_cast_for_escaping_regions(cx, source_ty, target_ty, span);
     match ty::get(target_ty).sty {
-        ty::ty_trait(box ty::TyTrait { bounds, .. }) => {
-            check_trait_cast_bounds(cx, span, source_ty, bounds);
-        }
+        ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ ty, .. }) => match ty::get(ty).sty {
+            ty::ty_trait(box ty::TyTrait { bounds, .. }) => {
+                check_trait_cast_bounds(cx, span, source_ty, bounds);
+            }
+            _ => {}
+        },
         _ => {}
     }
 }
@@ -530,9 +533,8 @@ pub fn check_cast_for_escaping_regions(
 {
     // Determine what type we are casting to; if it is not a trait, then no
     // worries.
-    match ty::get(target_ty).sty {
-        ty::ty_trait(..) => {}
-        _ => { return; }
+    if !ty::type_is_trait(target_ty) {
+        return;
     }
 
     // Collect up the regions that appear in the target type.  We want to

src/librustc/middle/lint.rs

@@ -980,9 +980,6 @@ fn check_heap_type(cx: &Context, span: Span, ty: ty::t) {
                     n_box += 1;
                 }
                 ty::ty_uniq(_) |
-                ty::ty_trait(box ty::TyTrait {
-                    store: ty::UniqTraitStore, ..
-                }) |
                 ty::ty_closure(box ty::ClosureTy {
                     store: ty::UniqTraitStore,
                     ..

src/librustc/middle/mem_categorization.rs

@@ -174,7 +174,6 @@ pub enum deref_kind {
 pub fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
     match ty::get(t).sty {
         ty::ty_uniq(_) |
-        ty::ty_trait(box ty::TyTrait { store: ty::UniqTraitStore, .. }) |
         ty::ty_closure(box ty::ClosureTy {store: ty::UniqTraitStore, ..}) => {
             Some(deref_ptr(OwnedPtr))
         }
@@ -183,13 +182,6 @@ pub fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
             let kind = ty::BorrowKind::from_mutbl(mt.mutbl);
             Some(deref_ptr(BorrowedPtr(kind, r)))
         }
-        ty::ty_trait(box ty::TyTrait {
-                store: ty::RegionTraitStore(r, mutbl),
-                ..
-            }) => {
-            let kind = ty::BorrowKind::from_mutbl(mutbl);
-            Some(deref_ptr(BorrowedPtr(kind, r)))
-        }
 
         ty::ty_closure(box ty::ClosureTy {
                 store: ty::RegionTraitStore(r, _),

src/librustc/middle/trans/adt.rs

@@ -292,12 +292,11 @@ impl Case {
     fn find_ptr(&self) -> Option<uint> {
         self.tys.iter().position(|&ty| {
             match ty::get(ty).sty {
-                ty::ty_rptr(_, mt) => match ty::get(mt.ty).sty {
-                    ty::ty_vec(_, None) | ty::ty_str => false,
+                ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ty, ..}) => match ty::get(ty).sty {
+                    ty::ty_vec(_, None) | ty::ty_str| ty::ty_trait(..) => false,
                     _ => true,
                 },
-                ty::ty_uniq(..) | ty::ty_box(..) |
-                ty::ty_bare_fn(..) => true,
+                ty::ty_box(..) | ty::ty_bare_fn(..) => true,
                 // Is that everything?  Would closures or slices qualify?
                 _ => false
             }

src/librustc/middle/trans/base.rs

@@ -1794,6 +1794,9 @@ pub fn get_fn_llvm_attributes(ccx: &CrateContext, fn_ty: ty::t) -> Vec<(uint, u6
         match ty::get(ret_ty).sty {
             // `~` pointer return values never alias because ownership
             // is transferred
+            ty::ty_uniq(it)  if match ty::get(it).sty {
+                ty::ty_str | ty::ty_vec(..) | ty::ty_trait(..) => true, _ => false
+            } => {}
             ty::ty_uniq(_) => {
                 attrs.push((lib::llvm::ReturnIndex as uint, lib::llvm::NoAliasAttribute as u64));
             }
@@ -1803,9 +1806,9 @@ pub fn get_fn_llvm_attributes(ccx: &CrateContext, fn_ty: ty::t) -> Vec<(uint, u6
         // We can also mark the return value as `nonnull` in certain cases
         match ty::get(ret_ty).sty {
             // These are not really pointers but pairs, (pointer, len)
-            ty::ty_rptr(_, ty::mt { ty: it, .. }) |
+            ty::ty_uniq(it) |
             ty::ty_rptr(_, ty::mt { ty: it, .. }) if match ty::get(it).sty {
-                ty::ty_str | ty::ty_vec(..) => true, _ => false
+                ty::ty_str | ty::ty_vec(..) | ty::ty_trait(..) => true, _ => false
             } => {}
             ty::ty_uniq(_) | ty::ty_rptr(_, _) => {
                 attrs.push((lib::llvm::ReturnIndex as uint, lib::llvm::NonNullAttribute as u64));

src/librustc/middle/trans/common.rs

@@ -67,7 +67,7 @@ pub fn type_is_immediate(ccx: &CrateContext, ty: ty::t) -> bool {
         ty::type_is_unique(ty) || ty::type_is_region_ptr(ty) ||
         type_is_newtype_immediate(ccx, ty) || ty::type_is_bot(ty) ||
         ty::type_is_simd(tcx, ty);
-    if simple {
+    if simple && !ty::type_is_trait(ty) {
         return true;
     }
     match ty::get(ty).sty {

src/librustc/middle/trans/consts.rs

@@ -143,7 +143,9 @@ fn const_deref(cx: &CrateContext, v: ValueRef, t: ty::t, explicit: bool)
             let dv = match ty::get(t).sty {
                 ty::ty_ptr(mt) | ty::ty_rptr(_, mt) => {
                     match ty::get(mt.ty).sty {
-                        ty::ty_vec(_, None) | ty::ty_str => cx.sess().bug("unexpected slice"),
+                        ty::ty_vec(_, None) | ty::ty_str | ty::ty_trait(..) => {
+                            cx.sess().bug("unexpected unsized type")
+                        }
                         _ => const_deref_ptr(cx, v),
                     }
                 }

src/librustc/middle/trans/datum.rs

@@ -157,9 +157,7 @@ pub fn appropriate_rvalue_mode(ccx: &CrateContext, ty: ty::t) -> RvalueMode {
      * on whether type is immediate or not.
      */
 
-    if type_is_zero_size(ccx, ty) {
-        ByValue
-    } else if type_is_immediate(ccx, ty) {
+    if type_is_immediate(ccx, ty) {
         ByValue
     } else {
         ByRef