auto merge of #11485 : eddyb/rust/sweep-old-rust, r=nikomatsakis

Author: bors

src/librustc/metadata/decoder.rs

@@ -782,7 +782,7 @@ fn get_explicit_self(item: ebml::Doc) -> ast::ExplicitSelf_ {
     match explicit_self_kind as char {
         's' => ast::SelfStatic,
         'v' => ast::SelfValue(get_mutability(string[1])),
-        '@' => ast::SelfBox(get_mutability(string[1])),
+        '@' => ast::SelfBox,
         '~' => ast::SelfUniq(get_mutability(string[1])),
         // FIXME(#4846) expl. region
         '&' => ast::SelfRegion(None, get_mutability(string[1])),

src/librustc/metadata/encoder.rs

@@ -687,9 +687,8 @@ fn encode_explicit_self(ebml_w: &mut writer::Encoder, explicit_self: ast::Explic
             ebml_w.writer.write(&[ '&' as u8 ]);
             encode_mutability(ebml_w, m);
         }
-        SelfBox(m) => {
+        SelfBox => {
             ebml_w.writer.write(&[ '@' as u8 ]);
-            encode_mutability(ebml_w, m);
         }
         SelfUniq(m) => {
             ebml_w.writer.write(&[ '~' as u8 ]);

src/librustc/metadata/tydecode.rs

@@ -343,7 +343,7 @@ fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
         return ty::mk_self(st.tcx, did);
       }
       '@' => return ty::mk_box(st.tcx, parse_ty(st, |x,y| conv(x,y))),
-      '~' => return ty::mk_uniq(st.tcx, parse_mt(st, |x,y| conv(x,y))),
+      '~' => return ty::mk_uniq(st.tcx, parse_ty(st, |x,y| conv(x,y))),
       '*' => return ty::mk_ptr(st.tcx, parse_mt(st, |x,y| conv(x,y))),
       '&' => {
         let r = parse_region(st, |x,y| conv(x,y));

src/librustc/metadata/tyencode.rs

@@ -292,7 +292,7 @@ fn enc_sty(w: &mut MemWriter, cx: @ctxt, st: &ty::sty) {
             mywrite!(w, "]");
         }
         ty::ty_box(typ) => { mywrite!(w, "@"); enc_ty(w, cx, typ); }
-        ty::ty_uniq(mt) => { mywrite!(w, "~"); enc_mt(w, cx, mt); }
+        ty::ty_uniq(typ) => { mywrite!(w, "~"); enc_ty(w, cx, typ); }
         ty::ty_ptr(mt) => { mywrite!(w, "*"); enc_mt(w, cx, mt); }
         ty::ty_rptr(r, mt) => {
             mywrite!(w, "&");

src/librustc/middle/borrowck/doc.rs

@@ -248,7 +248,7 @@ data as mutable).
 2. `LIFETIME(LV, LT, MQ)`: The lifetime of the borrow does not exceed
 the lifetime of the value being borrowed. This pass is also
 responsible for inserting root annotations to keep managed values
-alive and for dynamically freezing `@mut` boxes.
+alive.
 
 3. `RESTRICTIONS(LV, LT, ACTIONS) = RS`: This pass checks and computes the
 restrictions to maintain memory safety. These are the restrictions
@@ -308,22 +308,17 @@ be borrowed if MQ is immutable or const:
 
 ### Checking mutability of mutable pointer types
 
-`&mut T` and `@mut T` can be frozen, so it is acceptable to borrow
-them as either imm or mut:
+`&mut T` can be frozen, so it is acceptable to borrow it as either imm or mut:
 
     MUTABILITY(*LV, MQ)                 // M-Deref-Borrowed-Mut
       TYPE(LV) = &mut Ty
 
-    MUTABILITY(*LV, MQ)                 // M-Deref-Managed-Mut
-      TYPE(LV) = @mut Ty
-
 ## Checking lifetime
 
-These rules aim to ensure that no data is borrowed for a scope that
-exceeds its lifetime. In addition, these rules manage the rooting and
-dynamic freezing of `@` and `@mut` values. These two computations wind
-up being intimately related. Formally, we define a predicate
-`LIFETIME(LV, LT, MQ)`, which states that "the lvalue `LV` can be
+These rules aim to ensure that no data is borrowed for a scope that exceeds
+its lifetime. In addition, these rules manage the rooting of `@` values.
+These two computations wind up being intimately related. Formally, we define
+a predicate `LIFETIME(LV, LT, MQ)`, which states that "the lvalue `LV` can be
 safely borrowed for the lifetime `LT` with mutability `MQ`". The Rust
 code corresponding to this predicate is the module
 `middle::borrowck::gather_loans::lifetime`.
@@ -352,7 +347,7 @@ The scope of a managed referent is also the scope of the pointer.  This
 is a conservative approximation, since there may be other aliases fo
 that same managed box that would cause it to live longer:
 
-      SCOPE(*LV) = SCOPE(LV) if LV has type @T or @mut T
+      SCOPE(*LV) = SCOPE(LV) if LV has type @T
 
 The scope of a borrowed referent is the scope associated with the
 pointer.  This is a conservative approximation, since the data that
@@ -441,29 +436,6 @@ makes a note in a side-table that the box `LV` must be rooted into the
 stack when `*LV` is evaluated, and that this root can be released when
 the scope `LT` exits.
 
-### Checking lifetime for derefs of managed, mutable pointers
-
-Loans of the contents of mutable managed pointers are simpler in some
-ways that loans of immutable managed pointers, because we can never
-rely on the user to root them (since the contents are, after all,
-mutable). This means that the burden always falls to the compiler, so
-there is only one rule:
-
-    LIFETIME(*LV, LT, MQ)              // L-Deref-Managed-Mut-Compiler-Root
-      TYPE(LV) = @mut Ty
-      LT <= innermost enclosing loop/func
-      ROOT LV at *LV for LT
-      LOCK LV at *LV as MQ for LT
-
-Note that there is an additional clause this time `LOCK LV at *LV as
-MQ for LT`.  This clause states that in addition to rooting `LV`, the
-compiler should also "lock" the box dynamically, meaning that we
-register that the box has been borrowed as mutable or immutable,
-depending on `MQ`. This lock will fail if the box has already been
-borrowed and either the old loan or the new loan is a mutable loan
-(multiple immutable loans are okay). The lock is released as we exit
-the scope `LT`.
-
 ## Computing the restrictions
 
 The final rules govern the computation of *restrictions*, meaning that
@@ -835,15 +807,6 @@ prohibited from both freezes and claims. This would avoid the need to
 prevent `const` borrows of the base pointer when the referent is
 borrowed.
 
-### Restrictions for loans of mutable managed referents
-
-With `@mut` referents, we don't make any static guarantees.  But as a
-convenience, we still register a restriction against `*LV`, because
-that way if we *can* find a simple static error, we will:
-
-    RESTRICTIONS(*LV, LT, ACTIONS) = [*LV, ACTIONS]   // R-Deref-Managed-Borrowed
-      TYPE(LV) = @mut Ty
-
 # Moves and initialization
 
 The borrow checker is also in charge of ensuring that:

src/librustc/middle/borrowck/gather_loans/lifetime.rs

@@ -137,7 +137,7 @@ impl<'a> GuaranteeLifetimeContext<'a> {
                 //
                 // As a second example, consider *this* scenario:
                 //
-                //    let x = @mut @Some(3);
+                //    let x = @@Some(3);
                 //    match x { @@Some(y) {...} @@None {...} }
                 //
                 // Here again, `x` need only be rooted in the `some` arm.
@@ -156,7 +156,7 @@ impl<'a> GuaranteeLifetimeContext<'a> {
                 // with a second basic block.  However, the naive approach
                 // also yielded suboptimal results for patterns like:
                 //
-                //    let x = @mut @...;
+                //    let x = @@...;
                 //    match x { @@some_variant(y) | @@some_other_variant(y) =>
                 //
                 // The reason is that we would root the value once for

src/librustc/middle/liveness.rs

@@ -409,7 +409,7 @@ fn visit_fn(v: &mut LivenessVisitor,
     match *fk {
         visit::FkMethod(_, _, method) => {
             match method.explicit_self.node {
-                SelfValue(_) | SelfRegion(..) | SelfBox(_) | SelfUniq(_) => {
+                SelfValue(_) | SelfRegion(..) | SelfBox | SelfUniq(_) => {
                     fn_maps.add_variable(Arg(method.self_id,
                                              special_idents::self_));
                 }

src/librustc/middle/trans/base.rs

@@ -357,20 +357,18 @@ pub fn malloc_raw_dyn<'a>(
         rslt(r.bcx, PointerCast(r.bcx, r.val, llty_value.ptr_to()))
     } else {
         // we treat ~fn, @fn and @[] as @ here, which isn't ideal
-        let (mk_fn, langcall) = match heap {
+        let langcall = match heap {
             heap_managed | heap_managed_unique => {
-                (ty::mk_imm_box,
-                 require_alloc_fn(bcx, t, MallocFnLangItem))
+                require_alloc_fn(bcx, t, MallocFnLangItem)
             }
             heap_exchange_closure => {
-                (ty::mk_imm_box,
-                 require_alloc_fn(bcx, t, ClosureExchangeMallocFnLangItem))
+                require_alloc_fn(bcx, t, ClosureExchangeMallocFnLangItem)
             }
             _ => fail!("heap_exchange already handled")
         };
 
         // Grab the TypeRef type of box_ptr_ty.
-        let box_ptr_ty = mk_fn(bcx.tcx(), t);
+        let box_ptr_ty = ty::mk_box(bcx.tcx(), t);
         let llty = type_of(ccx, box_ptr_ty);
 
         // Get the tydesc for the body:

src/librustc/middle/trans/closure.rs

@@ -131,11 +131,6 @@ impl EnvValue {
     }
 }
 
-pub fn mk_tuplified_uniq_cbox_ty(tcx: ty::ctxt, cdata_ty: ty::t) -> ty::t {
-    let cbox_ty = tuplify_box_ty(tcx, cdata_ty);
-    return ty::mk_imm_uniq(tcx, cbox_ty);
-}
-
 // Given a closure ty, emits a corresponding tuple ty
 pub fn mk_closure_tys(tcx: ty::ctxt,
                       bound_values: &[EnvValue])

src/librustc/middle/trans/datum.rs

@@ -569,7 +569,7 @@ impl Datum {
 
         let (content_ty, header) = match ty::get(self.ty).sty {
             ty::ty_box(typ) => (typ, true),
-            ty::ty_uniq(mt) => (mt.ty, false),
+            ty::ty_uniq(typ) => (typ, false),
             ty::ty_vec(_, ty::vstore_uniq) | ty::ty_str(ty::vstore_uniq) => {
                 let unit_ty = ty::sequence_element_type(bcx.tcx(), self.ty);
                 let unboxed_vec_ty = ty::mk_mut_unboxed_vec(bcx.tcx(), unit_ty);

src/librustc/middle/trans/debuginfo.rs

@@ -2164,12 +2164,15 @@ fn type_metadata(cx: &CrateContext,
                 }
             }
         },
-        ty::ty_uniq(ref mt) if ty::type_contents(cx.tcx, mt.ty).owns_managed() => {
-            create_pointer_to_box_metadata(cx, t, mt.ty)
-        },
-        ty::ty_uniq(ref mt)    |
-        ty::ty_ptr(ref mt)     |
-        ty::ty_rptr(_, ref mt) => {
+        ty::ty_uniq(typ) => {
+            if ty::type_contents(cx.tcx, typ).owns_managed() {
+                create_pointer_to_box_metadata(cx, t, typ)
+            } else {
+                let pointee = type_metadata(cx, typ, usage_site_span);
+                pointer_type_metadata(cx, t, pointee)
+            }
+        }
+        ty::ty_ptr(ref mt) | ty::ty_rptr(_, ref mt) => {
             let pointee = type_metadata(cx, mt.ty, usage_site_span);
             pointer_type_metadata(cx, t, pointee)
         },
@@ -2193,7 +2196,7 @@ fn type_metadata(cx: &CrateContext,
 
     let mut created_types = debug_context(cx).created_types.borrow_mut();
     created_types.get().insert(cache_id, type_metadata);
-    return type_metadata;
+    type_metadata
 }
 
 #[deriving(Eq)]

src/librustc/middle/trans/glue.rs

@@ -108,22 +108,26 @@ fn simplified_glue_type(tcx: ty::ctxt, field: uint, t: ty::t) -> ty::t {
     }
 
     if field == abi::tydesc_field_take_glue && ty::type_is_boxed(t) {
-        return ty::mk_imm_box(tcx, ty::mk_nil());
+        return ty::mk_box(tcx, ty::mk_nil());
     }
 
     if field == abi::tydesc_field_drop_glue {
         match ty::get(t).sty {
             ty::ty_box(typ)
                 if !ty::type_needs_drop(tcx, typ) =>
-            return ty::mk_imm_box(tcx, ty::mk_nil()),
+            return ty::mk_box(tcx, ty::mk_nil()),
 
             ty::ty_vec(mt, ty::vstore_box)
                 if !ty::type_needs_drop(tcx, mt.ty) =>
-            return ty::mk_imm_box(tcx, ty::mk_nil()),
+            return ty::mk_box(tcx, ty::mk_nil()),
 
-            ty::ty_uniq(mt) | ty::ty_vec(mt, ty::vstore_uniq)
+            ty::ty_uniq(typ)
+                if !ty::type_needs_drop(tcx, typ) =>
+            return ty::mk_uniq(tcx, ty::mk_nil()),
+
+            ty::ty_vec(mt, ty::vstore_uniq)
                 if !ty::type_needs_drop(tcx, mt.ty) =>
-            return ty::mk_imm_uniq(tcx, ty::mk_nil()),
+            return ty::mk_uniq(tcx, ty::mk_nil()),
 
             _ => {}
         }

src/librustc/middle/trans/reflect.rs

@@ -176,6 +176,7 @@ impl<'a> Reflector<'a> {
               self.visit("vec", values)
           }
 
+          // Should rename to str_*/vec_*.
           ty::ty_str(vst) => {
               let (name, extra) = self.vstore_name_and_extra(t, vst);
               self.visit(~"estr_" + name, extra)
@@ -189,15 +190,19 @@ impl<'a> Reflector<'a> {
                   self.visit(~"evec_" + name, extra)
               }
           }
+          // Should remove mt from box and uniq.
           ty::ty_box(typ) => {
               let extra = self.c_mt(&ty::mt {
                   ty: typ,
                   mutbl: ast::MutImmutable,
               });
               self.visit("box", extra)
           }
-          ty::ty_uniq(ref mt) => {
-              let extra = self.c_mt(mt);
+          ty::ty_uniq(typ) => {
+              let extra = self.c_mt(&ty::mt {
+                  ty: typ,
+                  mutbl: ast::MutImmutable,
+              });
               if ty::type_contents(bcx.tcx(), t).owns_managed() {
                   self.visit("uniq_managed", extra)
               } else {

src/librustc/middle/trans/tvec.rs

@@ -39,14 +39,14 @@ pub fn expand_boxed_vec_ty(tcx: ty::ctxt, t: ty::t) -> ty::t {
     let unit_ty = ty::sequence_element_type(tcx, t);
     let unboxed_vec_ty = ty::mk_mut_unboxed_vec(tcx, unit_ty);
     match ty::get(t).sty {
-      ty::ty_str(ty::vstore_uniq) | ty::ty_vec(_, ty::vstore_uniq) => {
-        ty::mk_imm_uniq(tcx, unboxed_vec_ty)
-      }
-      ty::ty_str(ty::vstore_box) | ty::ty_vec(_, ty::vstore_box) => {
-        ty::mk_imm_box(tcx, unboxed_vec_ty)
-      }
-      _ => tcx.sess.bug("non boxed-vec type \
-                         in tvec::expand_boxed_vec_ty")
+        ty::ty_str(ty::vstore_uniq) | ty::ty_vec(_, ty::vstore_uniq) => {
+            ty::mk_uniq(tcx, unboxed_vec_ty)
+        }
+        ty::ty_str(ty::vstore_box) | ty::ty_vec(_, ty::vstore_box) => {
+            ty::mk_box(tcx, unboxed_vec_ty)
+        }
+        _ => tcx.sess.bug("non boxed-vec type \
+                           in tvec::expand_boxed_vec_ty")
     }
 }
 

src/librustc/middle/trans/type_of.rs

@@ -244,9 +244,9 @@ pub fn type_of(cx: &CrateContext, t: ty::t) -> Type {
           let ty = type_of(cx, typ);
           Type::smart_ptr(cx, &ty).ptr_to()
       }
-      ty::ty_uniq(ref mt) => {
-          let ty = type_of(cx, mt.ty);
-          if ty::type_contents(cx.tcx, mt.ty).owns_managed() {
+      ty::ty_uniq(typ) => {
+          let ty = type_of(cx, typ);
+          if ty::type_contents(cx.tcx, typ).owns_managed() {
               Type::unique(cx, &ty).ptr_to()
           } else {
               ty.ptr_to()

src/librustc/middle/trans/write_guard.rs

@@ -8,8 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-//! Logic relating to rooting and write guards for managed values
-//! (`@` and `@mut`). This code is primarily for use by datum;
+//! Logic relating to rooting and write guards for managed values.
+//! This code is primarily for use by datum;
 //! it exists in its own module both to keep datum.rs bite-sized
 //! and for each in debugging (e.g., so you can use
 //! `RUST_LOG=rustc::middle::trans::write_guard`).