librustc: Forbid & pointers (other than &'static) inside @ boxes.

This makes custom borrowing implementations for custom smart pointers
sound.

Author: pcwalton

src/libextra/fun_treemap.rs

@@ -31,10 +31,17 @@ enum TreeNode<K, V> {
 }
 
 /// Create a treemap
-pub fn init<K, V>() -> Treemap<K, V> { @Empty }
+pub fn init<K: 'static, V: 'static>() -> Treemap<K, V> {
+    @Empty
+}
 
 /// Insert a value into the map
-pub fn insert<K:Eq + Ord,V>(m: Treemap<K, V>, k: K, v: V) -> Treemap<K, V> {
+pub fn insert<K:Eq + Ord + 'static,
+              V:'static>(
+              m: Treemap<K, V>,
+              k: K,
+              v: V)
+              -> Treemap<K, V> {
     @match m {
         @Empty => Node(@k, @v, @Empty, @Empty),
         @Node(kk, vv, left, right) => cond!(
@@ -46,7 +53,11 @@ pub fn insert<K:Eq + Ord,V>(m: Treemap<K, V>, k: K, v: V) -> Treemap<K, V> {
 }
 
 /// Find a value based on the key
-pub fn find<K:Eq + Ord,V:Clone>(m: Treemap<K, V>, k: K) -> Option<V> {
+pub fn find<K:Eq + Ord + 'static,
+            V:Clone + 'static>(
+            m: Treemap<K, V>,
+            k: K)
+            -> Option<V> {
     match *m {
         Empty => None,
         Node(kk, v, left, right) => cond!(

src/libextra/list.rs

@@ -25,7 +25,7 @@ pub enum MutList<T> {
 }
 
 /// Create a list from a vector
-pub fn from_vec<T:Clone>(v: &[T]) -> @List<T> {
+pub fn from_vec<T:Clone + 'static>(v: &[T]) -> @List<T> {
     v.rev_iter().fold(@Nil::<T>, |t, h| @Cons((*h).clone(), t))
 }
 
@@ -109,7 +109,7 @@ pub fn head<T:Clone>(ls: @List<T>) -> T {
 }
 
 /// Appends one list to another
-pub fn append<T:Clone>(l: @List<T>, m: @List<T>) -> @List<T> {
+pub fn append<T:Clone + 'static>(l: @List<T>, m: @List<T>) -> @List<T> {
     match *l {
       Nil => return m,
       Cons(ref x, xs) => {

src/libextra/serialize.rs

@@ -423,7 +423,7 @@ impl<S:Encoder,T:Encodable<S>> Encodable<S> for @T {
     }
 }
 
-impl<D:Decoder,T:Decodable<D>> Decodable<D> for @T {
+impl<D:Decoder,T:Decodable<D> + 'static> Decodable<D> for @T {
     fn decode(d: &mut D) -> @T {
         @Decodable::decode(d)
     }
@@ -435,7 +435,7 @@ impl<S:Encoder,T:Encodable<S>> Encodable<S> for @mut T {
     }
 }
 
-impl<D:Decoder,T:Decodable<D>> Decodable<D> for @mut T {
+impl<D:Decoder,T:Decodable<D> + 'static> Decodable<D> for @mut T {
     fn decode(d: &mut D) -> @mut T {
         @mut Decodable::decode(d)
     }

src/librustc/metadata/encoder.rs

@@ -1259,8 +1259,9 @@ fn encode_info_for_items(ecx: &EncodeContext,
 
 // Path and definition ID indexing
 
-fn create_index<T:Clone + Hash + IterBytes>(index: ~[entry<T>])
-                                            -> ~[@~[entry<T>]] {
+fn create_index<T:Clone + Hash + IterBytes + 'static>(
+                index: ~[entry<T>])
+                -> ~[@~[entry<T>]] {
     let mut buckets: ~[@mut ~[entry<T>]] = ~[];
     for uint::range(0u, 256u) |_i| { buckets.push(@mut ~[]); };
     for index.iter().advance |elt| {
@@ -1275,9 +1276,10 @@ fn create_index<T:Clone + Hash + IterBytes>(index: ~[entry<T>])
     return buckets_frozen;
 }
 
-fn encode_index<T>(ebml_w: &mut writer::Encoder,
-                   buckets: ~[@~[entry<T>]],
-                   write_fn: &fn(@io::Writer, &T)) {
+fn encode_index<T:'static>(
+                ebml_w: &mut writer::Encoder,
+                buckets: ~[@~[entry<T>]],
+                write_fn: &fn(@io::Writer, &T)) {
     let writer = ebml_w.writer;
     ebml_w.start_tag(tag_index);
     let mut bucket_locs: ~[uint] = ~[];

src/librustc/middle/kind.rs

@@ -285,6 +285,10 @@ pub fn check_expr(e: @expr, (cx, v): (Context, visit::vt<Context>)) {
     }
 
     match e.node {
+        expr_unary(_, box(_), interior) => {
+            let interior_type = ty::expr_ty(cx.tcx, interior);
+            let _ = check_durable(cx.tcx, interior_type, interior.span);
+        }
         expr_cast(source, _) => {
             check_cast_for_escaping_regions(cx, source, e);
             match ty::get(ty::expr_ty(cx.tcx, e)).sty {

src/librustc/middle/subst.rs

@@ -79,7 +79,7 @@ impl<T:Subst> Subst for ~[T] {
     }
 }
 
-impl<T:Subst> Subst for @T {
+impl<T:Subst + 'static> Subst for @T {
     fn subst(&self, tcx: ty::ctxt, substs: &ty::substs) -> @T {
         match self {
             &@ref t => @t.subst(tcx, substs)

src/librustc/middle/ty.rs

@@ -858,7 +858,7 @@ fn mk_rcache() -> creader_cache {
     return @mut HashMap::new();
 }
 
-pub fn new_ty_hash<V>() -> @mut HashMap<t, V> {
+pub fn new_ty_hash<V:'static>() -> @mut HashMap<t, V> {
     @mut HashMap::new()
 }
 

src/libstd/clone.rs

@@ -112,15 +112,15 @@ impl<T: DeepClone> DeepClone for ~T {
 }
 
 // FIXME: #6525: should also be implemented for `T: Send + DeepClone`
-impl<T: Freeze + DeepClone> DeepClone for @T {
+impl<T: Freeze + DeepClone + 'static> DeepClone for @T {
     /// Return a deep copy of the managed box. The `Freeze` trait is required to prevent performing
     /// a deep clone of a potentially cyclical type.
     #[inline]
     fn deep_clone(&self) -> @T { @(**self).deep_clone() }
 }
 
 // FIXME: #6525: should also be implemented for `T: Send + DeepClone`
-impl<T: Freeze + DeepClone> DeepClone for @mut T {
+impl<T: Freeze + DeepClone + 'static> DeepClone for @mut T {
     /// Return a deep copy of the managed box. The `Freeze` trait is required to prevent performing
     /// a deep clone of a potentially cyclical type.
     #[inline]

src/libstd/num/num.rs

@@ -446,12 +446,12 @@ pub fn pow_with_uint<T:NumCast+One+Zero+Div<T,T>+Mul<T,T>>(radix: uint, pow: uin
     total
 }
 
-impl<T: Zero> Zero for @mut T {
+impl<T: Zero + 'static> Zero for @mut T {
     fn zero() -> @mut T { @mut Zero::zero() }
     fn is_zero(&self) -> bool { (**self).is_zero() }
 }
 
-impl<T: Zero> Zero for @T {
+impl<T: Zero + 'static> Zero for @T {
     fn zero() -> @T { @Zero::zero() }
     fn is_zero(&self) -> bool { (**self).is_zero() }
 }

src/libstd/rand.rs

@@ -242,7 +242,7 @@ impl<T: Rand> Rand for ~T {
     fn rand<R: Rng>(rng: &mut R) -> ~T { ~rng.gen() }
 }
 
-impl<T: Rand> Rand for @T {
+impl<T: Rand + 'static> Rand for @T {
     #[inline]
     fn rand<R: Rng>(rng: &mut R) -> @T { @rng.gen() }
 }