prevent regions from escaping in ifaces; remove &r.T syntax

src/libcore/task.rs

@@ -832,10 +832,10 @@ fn spawn_raw(opts: task_opts, +f: fn~()) {
  * types; arbitrary type coercion is possible this way. The interface is safe
  * as long as all key functions are monomorphic.
  */
-type local_data_key<T> = fn@(+@T);
+type local_data_key<T: owned> = fn@(+@T);
 
 iface local_data { }
-impl<T> of local_data for @T { }
+impl<T: owned> of local_data for @T { }
 
 // We use dvec because it's the best data structure in core. If TLS is used
 // heavily in future, this could be made more efficient with a proper map.
@@ -852,6 +852,7 @@ extern fn cleanup_task_local_map(map_ptr: *libc::c_void) unsafe {
 
 // Gets the map from the runtime. Lazily initialises if not done so already.
 unsafe fn get_task_local_map(task: *rust_task) -> task_local_map {
+
     // Relies on the runtime initialising the pointer to null.
     // NOTE: The map's box lives in TLS invisibly referenced once. Each time
     // we retrieve it for get/set, we make another reference, which get/set
@@ -872,7 +873,9 @@ unsafe fn get_task_local_map(task: *rust_task) -> task_local_map {
     }
 }
 
-unsafe fn key_to_key_value<T>(key: local_data_key<T>) -> *libc::c_void {
+unsafe fn key_to_key_value<T: owned>(
+    key: local_data_key<T>) -> *libc::c_void {
+
     // Keys are closures, which are (fnptr,envptr) pairs. Use fnptr.
     // Use reintepret_cast -- transmute would leak (forget) the closure.
     let pair: (*libc::c_void, *libc::c_void) = unsafe::reinterpret_cast(key);
@@ -880,8 +883,10 @@ unsafe fn key_to_key_value<T>(key: local_data_key<T>) -> *libc::c_void {
 }
 
 // If returning some(..), returns with @T with the map's reference. Careful!
-unsafe fn local_data_lookup<T>(map: task_local_map, key: local_data_key<T>)
+unsafe fn local_data_lookup<T: owned>(
+    map: task_local_map, key: local_data_key<T>)
     -> option<(uint, *libc::c_void)> {
+
     let key_value = key_to_key_value(key);
     let map_pos = (*map).position(|entry|
         alt entry { some((k,_,_)) { k == key_value } none { false } }
@@ -893,8 +898,10 @@ unsafe fn local_data_lookup<T>(map: task_local_map, key: local_data_key<T>)
     }
 }
 
-unsafe fn local_get_helper<T>(task: *rust_task, key: local_data_key<T>,
+unsafe fn local_get_helper<T: owned>(
+    task: *rust_task, key: local_data_key<T>,
     do_pop: bool) -> option<@T> {
+
     let map = get_task_local_map(task);
     // Interpret our findings from the map
     do local_data_lookup(map, key).map |result| {
@@ -912,17 +919,23 @@ unsafe fn local_get_helper<T>(task: *rust_task, key: local_data_key<T>,
     }
 }
 
-unsafe fn local_pop<T>(task: *rust_task,
+unsafe fn local_pop<T: owned>(
+    task: *rust_task,
     key: local_data_key<T>) -> option<@T> {
+
     local_get_helper(task, key, true)
 }
 
-unsafe fn local_get<T>(task: *rust_task,
+unsafe fn local_get<T: owned>(
+    task: *rust_task,
     key: local_data_key<T>) -> option<@T> {
+
     local_get_helper(task, key, false)
 }
 
-unsafe fn local_set<T>(task: *rust_task, key: local_data_key<T>, +data: @T) {
+unsafe fn local_set<T: owned>(
+    task: *rust_task, key: local_data_key<T>, +data: @T) {
+
     let map = get_task_local_map(task);
     // Store key+data as *voids. Data is invisibly referenced once; key isn't.
     let keyval = key_to_key_value(key);
@@ -956,8 +969,10 @@ unsafe fn local_set<T>(task: *rust_task, key: local_data_key<T>, +data: @T) {
     }
 }
 
-unsafe fn local_modify<T>(task: *rust_task, key: local_data_key<T>,
+unsafe fn local_modify<T: owned>(
+    task: *rust_task, key: local_data_key<T>,
     modify_fn: fn(option<@T>) -> option<@T>) {
+
     // Could be more efficient by doing the lookup work, but this is easy.
     let newdata = modify_fn(local_pop(task, key));
     if newdata.is_some() {
@@ -970,29 +985,37 @@ unsafe fn local_modify<T>(task: *rust_task, key: local_data_key<T>,
  * Remove a task-local data value from the table, returning the
  * reference that was originally created to insert it.
  */
-unsafe fn local_data_pop<T>(key: local_data_key<T>) -> option<@T> {
+unsafe fn local_data_pop<T: owned>(
+    key: local_data_key<T>) -> option<@T> {
+
     local_pop(rustrt::rust_get_task(), key)
 }
 /**
  * Retrieve a task-local data value. It will also be kept alive in the
  * table until explicitly removed.
  */
-unsafe fn local_data_get<T>(key: local_data_key<T>) -> option<@T> {
+unsafe fn local_data_get<T: owned>(
+    key: local_data_key<T>) -> option<@T> {
+
     local_get(rustrt::rust_get_task(), key)
 }
 /**
  * Store a value in task-local data. If this key already has a value,
  * that value is overwritten (and its destructor is run).
  */
-unsafe fn local_data_set<T>(key: local_data_key<T>, +data: @T) {
+unsafe fn local_data_set<T: owned>(
+    key: local_data_key<T>, +data: @T) {
+
     local_set(rustrt::rust_get_task(), key, data)
 }
 /**
  * Modify a task-local data value. If the function returns 'none', the
  * data is removed (and its reference dropped).
  */
-unsafe fn local_data_modify<T>(key: local_data_key<T>,
+unsafe fn local_data_modify<T: owned>(
+    key: local_data_key<T>,
     modify_fn: fn(option<@T>) -> option<@T>) {
+
     local_modify(rustrt::rust_get_task(), key, modify_fn)
 }
 

src/libstd/deque.rs

@@ -193,7 +193,9 @@ mod tests {
 
     type eqfn<T> = fn@(T, T) -> bool;
 
-    fn test_parameterized<T: copy>(e: eqfn<T>, a: T, b: T, c: T, d: T) {
+    fn test_parameterized<T: copy owned>(
+        e: eqfn<T>, a: T, b: T, c: T, d: T) {
+
         let deq: deque::t<T> = deque::create::<T>();
         assert (deq.size() == 0u);
         deq.add_front(a);

src/libsyntax/parse/parser.rs

@@ -383,8 +383,7 @@ class parser {
         let name =
             alt copy self.token {
               token::IDENT(sid, _) => {
-                if self.look_ahead(1u) == token::DOT || // backwards compat
+                if self.look_ahead(1u) == token::BINOP(token::SLASH) {
-                    self.look_ahead(1u) == token::BINOP(token::SLASH) {
                     self.bump(); self.bump();
                     some(self.get_str(sid))
                 } else {

src/libsyntax/print/pprust.rs

@@ -345,7 +345,7 @@ fn print_type_ex(s: ps, &&ty: @ast::ty, print_colons: bool) {
       ast::ty_rptr(region, mt) {
         alt region.node {
           ast::re_anon { word(s.s, ~"&"); }
-          _ { print_region(s, region); word(s.s, ~"."); }
+          _ { print_region(s, region); word(s.s, ~"/"); }
         }
         print_mt(s, mt);
       }

src/rustc/metadata/tyencode.rs

@@ -272,7 +272,7 @@ fn enc_sty(w: io::writer, cx: @ctxt, st: ty::sty) {
         w.write_char('I');
         w.write_uint(id.to_uint());
       }
-      ty::ty_param(id, did) {
+      ty::ty_param({idx: id, def_id: did}) {
         w.write_char('p');
         w.write_str(cx.ds(did));
         w.write_char('|');

src/rustc/middle/kind.rs

@@ -115,7 +115,7 @@ fn with_appropriate_checker(cx: ctx, id: node_id, b: fn(check_fn)) {
     fn check_for_box(cx: ctx, id: node_id, fv: option<@freevar_entry>,
                      is_move: bool, var_t: ty::t, sp: span) {
         // all captured data must be owned
-        if !check_owned(cx, var_t, sp) { ret; }
+        if !check_owned(cx.tcx, var_t, sp) { ret; }
 
         // copied in data must be copyable, but moved in data can be anything
         let is_implicit = fv.is_some();
@@ -217,7 +217,13 @@ fn check_expr(e: @expr, cx: ctx, v: visit::vt<ctx>) {
     alt e.node {
       expr_assign(_, ex) |
       expr_unary(box(_), ex) | expr_unary(uniq(_), ex) |
-      expr_ret(some(ex)) | expr_cast(ex, _) { maybe_copy(cx, ex); }
+      expr_ret(some(ex)) {
+        maybe_copy(cx, ex);
+      }
+      expr_cast(source, _) {
+        maybe_copy(cx, source);
+        check_cast_for_escaping_regions(cx, source, e);
+      }
       expr_copy(expr) { check_copy_ex(cx, expr, false); }
       // Vector add copies, but not "implicitly"
       expr_assign_op(_, _, ex) { check_copy_ex(cx, ex, false) }
@@ -440,15 +446,92 @@ fn check_send(cx: ctx, ty: ty::t, sp: span) -> bool {
     }
 }
 
-fn check_owned(cx: ctx, ty: ty::t, sp: span) -> bool {
+// note: also used from middle::typeck::regionck!
-    if !ty::kind_is_owned(ty::type_kind(cx.tcx, ty)) {
+fn check_owned(tcx: ty::ctxt, ty: ty::t, sp: span) -> bool {
-        cx.tcx.sess.span_err(sp, ~"not an owned value");
+    if !ty::kind_is_owned(ty::type_kind(tcx, ty)) {
+        alt ty::get(ty).struct {
+          ty::ty_param(*) {
+            tcx.sess.span_err(sp, ~"value may contain borrowed \
+                                    pointers; use `owned` bound");
+          }
+          _ {
+            tcx.sess.span_err(sp, ~"value may contain borrowed \
+                                    pointers");
+          }
+        }
         false
     } else {
         true
     }
 }
 
+/// This is rather subtle.  When we are casting a value to a
+/// instantiated iface like `a as iface/&r`, regionck already ensures
+/// that any borrowed pointers that appear in the type of `a` are
+/// bounded by `&r`.  However, it is possible that there are *type
+/// parameters* in the type of `a`, and those *type parameters* may
+/// have borrowed pointers within them.  We have to guarantee that the
+/// regions which appear in those type parameters are not obscured.
+///
+/// Therefore, we ensure that one of three conditions holds:
+///
+/// (1) The iface instance cannot escape the current fn.  This is
+/// guaranteed if the region bound `&r` is some scope within the fn
+/// itself.  This case is safe because whatever borrowed pointers are
+/// found within the type parameter, they must enclose the fn body
+/// itself.
+///
+/// (2) The type parameter appears in the type of the iface.  For
+/// example, if the type parameter is `T` and the iface type is
+/// `deque<T>`, then whatever borrowed ptrs may appear in `T` also
+/// appear in `deque<T>`.
+///
+/// (3) The type parameter is owned (and therefore does not contain
+/// borrowed ptrs).
+fn check_cast_for_escaping_regions(
+    cx: ctx,
+    source: @expr,
+    target: @expr) {
+
+    // Determine what type we are casting to; if it is not an iface, then no
+    // worries.
+    let target_ty = ty::expr_ty(cx.tcx, target);
+    let target_substs = alt ty::get(target_ty).struct {
+      ty::ty_trait(_, substs) => {substs}
+      _ => { ret; /* not a cast to a trait */ }
+    };
+
+    // Check, based on the region associated with the iface, whether it can
+    // possibly escape the enclosing fn item (note that all type parameters
+    // must have been declared on the enclosing fn item):
+    alt target_substs.self_r {
+      some(ty::re_scope(*)) => { ret; /* case (1) */ }
+      none | some(ty::re_static) | some(ty::re_free(*)) => {}
+      some(ty::re_bound(*)) | some(ty::re_var(*)) => {
+        cx.tcx.sess.span_bug(
+            source.span,
+            #fmt["bad region found in kind: %?", target_substs.self_r]);
+      }
+    }
+
+    // Assuming the iface instance can escape, then ensure that each parameter
+    // either appears in the iface type or is owned:
+    let target_params = ty::param_tys_in_type(target_ty);
+    let source_ty = ty::expr_ty(cx.tcx, source);
+    do ty::walk_ty(source_ty) |ty| {
+        alt ty::get(ty).struct {
+          ty::ty_param(source_param) => {
+            if target_params.contains(source_param) {
+                /* case (2) */
+            } else {
+                check_owned(cx.tcx, ty, source.span); /* case (3) */
+            }
+          }
+          _ => {}
+        }
+    }
+}
+
 //
 // Local Variables:
 // mode: rust

src/rustc/middle/trans/base.rs

@@ -1317,7 +1317,7 @@ enum copy_action { INIT, DROP_EXISTING, }
 fn type_is_structural_or_param(t: ty::t) -> bool {
     if ty::type_is_structural(t) { ret true; }
     alt ty::get(t).struct {
-      ty::ty_param(_, _) { ret true; }
+      ty::ty_param(*) { ret true; }
       _ { ret false; }
     }
 }

src/rustc/middle/trans/reflect.rs

@@ -272,7 +272,7 @@ impl methods for reflector {
           ty::ty_trait(_, _) { self.leaf(~"trait") }
           ty::ty_var(_) { self.leaf(~"var") }
           ty::ty_var_integral(_) { self.leaf(~"var_integral") }
-          ty::ty_param(n, _) { self.visit(~"param", ~[self.c_uint(n)]) }
+          ty::ty_param(p) { self.visit(~"param", ~[self.c_uint(p.idx)]) }
           ty::ty_self { self.leaf(~"self") }
           ty::ty_type { self.leaf(~"type") }
           ty::ty_opaque_box { self.leaf(~"opaque_box") }

src/rustc/middle/trans/type_use.rs

@@ -137,8 +137,8 @@ fn type_needs_inner(cx: ctx, use: uint, ty: ty::t,
                 }
                 false
               }
-              ty::ty_param(n, _) {
+              ty::ty_param(p) {
-                cx.uses[n] |= use;
+                cx.uses[p.idx] |= use;
                 false
               }
               _ { true }

src/rustc/middle/ty.rs

@@ -166,6 +166,7 @@ export terr_regions_differ, terr_mutability, terr_purity_mismatch;
 export terr_proto_mismatch;
 export terr_ret_style_mismatch;
 export purity_to_str;
+export param_tys_in_type;
 
 // Data types
 
@@ -312,6 +313,8 @@ type fn_ty = {purity: ast::purity,
               output: t,
               ret_style: ret_style};
 
+type param_ty = {idx: uint, def_id: def_id};
+
 // See discussion at head of region.rs
 enum region {
     re_bound(bound_region),
@@ -370,7 +373,7 @@ enum sty {
     ty_var(tv_vid), // type variable during typechecking
     ty_var_integral(tvi_vid), // type variable during typechecking, for
                               // integral types only
-    ty_param(uint, def_id), // type parameter
+    ty_param(param_ty), // type parameter
     ty_self, // special, implicit `self` type parameter
 
     // "Fake" types, used for trans purposes
@@ -579,7 +582,7 @@ fn mk_t_with_id(cx: ctxt, st: sty, o_def_id: option<ast::def_id>) -> t {
       ty_nil | ty_bot | ty_bool | ty_int(_) | ty_float(_) | ty_uint(_) |
       ty_estr(_) | ty_type | ty_opaque_closure_ptr(_) |
       ty_opaque_box {}
-      ty_param(_, _) { flags |= has_params as uint; }
+      ty_param(_) { flags |= has_params as uint; }
       ty_var(_) | ty_var_integral(_) { flags |= needs_infer as uint; }
       ty_self { flags |= has_self as uint; }
       ty_enum(_, substs) | ty_class(_, substs) | ty_trait(_, substs) {
@@ -713,7 +716,9 @@ fn mk_var_integral(cx: ctxt, v: tvi_vid) -> t {
 
 fn mk_self(cx: ctxt) -> t { mk_t(cx, ty_self) }
 
-fn mk_param(cx: ctxt, n: uint, k: def_id) -> t { mk_t(cx, ty_param(n, k)) }
+fn mk_param(cx: ctxt, n: uint, k: def_id) -> t {
+    mk_t(cx, ty_param({idx: n, def_id: k}))
+}
 
 fn mk_type(cx: ctxt) -> t { mk_t(cx, ty_type) }
 
@@ -761,7 +766,7 @@ fn maybe_walk_ty(ty: t, f: fn(t) -> bool) {
       ty_nil | ty_bot | ty_bool | ty_int(_) | ty_uint(_) | ty_float(_) |
       ty_estr(_) | ty_type | ty_opaque_box | ty_self |
       ty_opaque_closure_ptr(_) | ty_var(_) | ty_var_integral(_) |
-      ty_param(_, _) {
+      ty_param(_) {
       }
       ty_box(tm) | ty_evec(tm, _) | ty_unboxed_vec(tm) |
       ty_ptr(tm) | ty_rptr(_, tm) {
@@ -982,7 +987,7 @@ fn subst_tps(cx: ctxt, tps: ~[t], typ: t) -> t {
     let tb = ty::get(typ);
     if !tbox_has_flag(tb, has_params) { ret typ; }
     alt tb.struct {
-      ty_param(idx, _) { tps[idx] }
+      ty_param(p) { tps[p.idx] }
       sty { fold_sty_to_ty(cx, sty, |t| subst_tps(cx, tps, t)) }
     }
 }
@@ -1019,7 +1024,7 @@ fn subst(cx: ctxt,
         let tb = get(typ);
         if !tbox_has_flag(tb, needs_subst) { ret typ; }
         alt tb.struct {
-          ty_param(idx, _) {substs.tps[idx]}
+          ty_param(p) {substs.tps[p.idx]}
           ty_self {substs.self_ty.get()}
           _ {
             fold_regions_and_ty(
@@ -1608,8 +1613,8 @@ fn type_kind(cx: ctxt, ty: t) -> kind {
         lowest
       }
 
-      ty_param(_, did) {
+      ty_param(p) {
-        param_bounds_to_kind(cx.ty_param_bounds.get(did.node))
+        param_bounds_to_kind(cx.ty_param_bounds.get(p.def_id.node))
       }
 
       // self is a special type parameter that can only appear in ifaces; it
@@ -1666,7 +1671,7 @@ fn is_instantiable(cx: ctxt, r_ty: t) -> bool {
           ty_fn(_) |
           ty_var(_) |
           ty_var_integral(_) |
-          ty_param(_, _) |
+          ty_param(_) |
           ty_self |
           ty_type |
           ty_opaque_box |
@@ -1855,7 +1860,7 @@ fn type_is_pod(cx: ctxt, ty: t) -> bool {
       ty_evec(mt, vstore_fixed(_)) | ty_unboxed_vec(mt) {
         result = type_is_pod(cx, mt.ty);
       }
-      ty_param(_, _) { result = false; }
+      ty_param(_) { result = false; }
       ty_opaque_closure_ptr(_) { result = true; }
       ty_class(did, substs) {
         result = vec::any(lookup_class_fields(cx, did), |f| {
@@ -1899,7 +1904,7 @@ fn type_is_c_like_enum(cx: ctxt, ty: t) -> bool {
 
 fn type_param(ty: t) -> option<uint> {
     alt get(ty).struct {
-      ty_param(id, _) { ret some(id); }
+      ty_param(p) { ret some(p.idx); }
       _ {/* fall through */ }
     }
     ret none;
@@ -2038,7 +2043,7 @@ fn hash_type_structure(st: sty) -> uint {
       ty_self { 28u }
       ty_var(v) { hash_uint(29u, v.to_uint()) }
       ty_var_integral(v) { hash_uint(30u, v.to_uint()) }
-      ty_param(pid, did) { hash_def(hash_uint(31u, pid), did) }
+      ty_param(p) { hash_def(hash_uint(31u, p.idx), p.def_id) }
       ty_type { 32u }
       ty_bot { 34u }
       ty_ptr(mt) { hash_subty(35u, mt.ty) }
@@ -2219,6 +2224,22 @@ fn method_idx(id: ast::ident, meths: ~[method]) -> option<uint> {
     ret none;
 }
 
+/// Returns a vector containing the indices of all type parameters that appear
+/// in `ty`.  The vector may contain duplicates.  Probably should be converted
+/// to a bitset or some other representation.
+fn param_tys_in_type(ty: t) -> ~[param_ty] {
+    let mut rslt = ~[];
+    do walk_ty(ty) |ty| {
+        alt get(ty).struct {
+          ty_param(p) {
+            vec::push(rslt, p);
+          }
+          _ { }
+        }
+    }
+    rslt
+}
+
 fn occurs_check(tcx: ctxt, sp: span, vid: tv_vid, rt: t) {
 
     // Returns a vec of all the type variables occurring in `ty`. It may
@@ -2341,7 +2362,7 @@ fn ty_sort_str(cx: ctxt, t: t) -> ~str {
       ty_tup(_) { ~"tuple" }
       ty_var(_) { ~"variable" }
       ty_var_integral(_) { ~"integral variable" }
-      ty_param(_, _) { ~"type parameter" }
+      ty_param(_) { ~"type parameter" }
       ty_self { ~"self" }
     }
 }

src/rustc/middle/typeck/astconv.rs

@@ -68,7 +68,7 @@ fn get_region_reporting_err(tcx: ty::ctxt,
     }
 }
 
-fn ast_region_to_region<AC: ast_conv, RS: region_scope>(
+fn ast_region_to_region<AC: ast_conv, RS: region_scope copy owned>(
     self: AC, rscope: RS, span: span, a_r: @ast::region) -> ty::region {
 
     let res = alt a_r.node {
@@ -79,7 +79,7 @@ fn ast_region_to_region<AC: ast_conv, RS: region_scope>(
     get_region_reporting_err(self.tcx(), span, res)
 }
 
-fn ast_path_to_substs_and_ty<AC: ast_conv, RS: region_scope copy>(
+fn ast_path_to_substs_and_ty<AC: ast_conv, RS: region_scope copy owned>(
     self: AC, rscope: RS, did: ast::def_id,
     path: @ast::path) -> ty_param_substs_and_ty {
 
@@ -128,7 +128,7 @@ fn ast_path_to_substs_and_ty<AC: ast_conv, RS: region_scope copy>(
     {substs: substs, ty: ty::subst(tcx, substs, decl_ty)}
 }
 
-fn ast_path_to_ty<AC: ast_conv, RS: region_scope copy>(
+fn ast_path_to_ty<AC: ast_conv, RS: region_scope copy owned>(
     self: AC,
     rscope: RS,
     did: ast::def_id,
@@ -151,10 +151,10 @@ const NO_TPS: uint = 2u;
 // Parses the programmer's textual representation of a type into our
 // internal notion of a type. `getter` is a function that returns the type
 // corresponding to a definition ID:
-fn ast_ty_to_ty<AC: ast_conv, RS: region_scope copy>(
+fn ast_ty_to_ty<AC: ast_conv, RS: region_scope copy owned>(
     self: AC, rscope: RS, &&ast_ty: @ast::ty) -> ty::t {
 
-    fn ast_mt_to_mt<AC: ast_conv, RS: region_scope copy>(
+    fn ast_mt_to_mt<AC: ast_conv, RS: region_scope copy owned>(
         self: AC, rscope: RS, mt: ast::mt) -> ty::mt {
 
         ret {ty: ast_ty_to_ty(self, rscope, mt.ty), mutbl: mt.mutbl};
@@ -162,7 +162,7 @@ fn ast_ty_to_ty<AC: ast_conv, RS: region_scope copy>(
 
     // Handle @, ~, and & being able to mean estrs and evecs.
     // If a_seq_ty is a str or a vec, make it an estr/evec
-    fn mk_maybe_vstore<AC: ast_conv, RS: region_scope copy>(
+    fn mk_maybe_vstore<AC: ast_conv, RS: region_scope copy owned>(
         self: AC, rscope: RS, a_seq_ty: ast::mt, vst: ty::vstore,
         constr: fn(ty::mt) -> ty::t) -> ty::t {
 
@@ -351,7 +351,7 @@ fn ast_ty_to_ty<AC: ast_conv, RS: region_scope copy>(
     ret typ;
 }
 
-fn ty_of_arg<AC: ast_conv, RS: region_scope copy>(
+fn ty_of_arg<AC: ast_conv, RS: region_scope copy owned>(
     self: AC, rscope: RS, a: ast::arg,
     expected_ty: option<ty::arg>) -> ty::arg {
 
@@ -394,7 +394,7 @@ fn ty_of_arg<AC: ast_conv, RS: region_scope copy>(
 type expected_tys = option<{inputs: ~[ty::arg],
                             output: ty::t}>;
 
-fn ty_of_fn_decl<AC: ast_conv, RS: region_scope copy>(
+fn ty_of_fn_decl<AC: ast_conv, RS: region_scope copy owned>(
     self: AC, rscope: RS,
     proto: ast::proto,
     decl: ast::fn_decl,

src/rustc/middle/typeck/check.rs

@@ -2154,7 +2154,7 @@ fn check_bounds_are_used(ccx: @crate_ctxt,
         |_r| {},
         |t| {
             alt ty::get(t).struct {
-              ty::ty_param(idx, _) { tps_used[idx] = true; }
+              ty::ty_param({idx, _}) { tps_used[idx] = true; }
               _ { }
             }
             true

src/rustc/middle/typeck/check/method.rs

@@ -87,8 +87,8 @@ class lookup {
         loop {
             // First, see whether this is an interface-bounded parameter.
             alt ty::get(self.self_ty).struct {
-              ty::ty_param(n, did) {
+              ty::ty_param(p) {
-                self.add_candidates_from_param(n, did);
+                self.add_candidates_from_param(p.idx, p.def_id);
               }
               ty::ty_trait(did, substs) {
                 self.add_candidates_from_trait(did, substs);

src/rustc/middle/typeck/check/regionck.rs

@@ -20,23 +20,59 @@ this point a bit better.
 import util::ppaux;
 import syntax::print::pprust;
 import infer::{resolve_type, resolve_all, force_all,
-               resolve_rvar, force_rvar};
+               resolve_rvar, force_rvar, fres};
+import middle::kind::check_owned;
 
-type rcx = @{fcx: @fn_ctxt, mut errors_reported: uint};
+enum rcx { rcx_({fcx: @fn_ctxt, mut errors_reported: uint}) }
-type rvt = visit::vt<rcx>;
+type rvt = visit::vt<@rcx>;
+
+impl methods for @rcx {
+    /// Try to resolve the type for the given node.
+    ///
+    /// Note one important point: we do not attempt to resolve *region
+    /// variables* here.  This is because regionck is essentially adding
+    /// constraints to those region variables and so may yet influence
+    /// how they are resolved.
+    ///
+    /// Consider this silly example:
+    ///
+    ///     fn borrow(x: &int) -> &int {x}
+    ///     fn foo(x: @int) -> int {  /* block: B */
+    ///         let b = borrow(x);    /* region: <R0> */
+    ///         *b
+    ///     }
+    ///
+    /// Here, the region of `b` will be `<R0>`.  `<R0>` is constrainted
+    /// to be some subregion of the block B and some superregion of
+    /// the call.  If we forced it now, we'd choose the smaller region
+    /// (the call).  But that would make the *b illegal.  Since we don't
+    /// resolve, the type of b will be `&<R0>.int` and then `*b` will require
+    /// that `<R0>` be bigger than the let and the `*b` expression, so we
+    /// will effectively resolve `<R0>` to be the block B.
+    fn resolve_type(unresolved_ty: ty::t) -> fres<ty::t> {
+        resolve_type(self.fcx.infcx, unresolved_ty,
+                     (resolve_all | force_all) -
+                     (resolve_rvar | force_rvar))
+    }
+
+    /// Try to resolve the type for the given node.
+    fn resolve_node_type(id: ast::node_id) -> fres<ty::t> {
+        self.resolve_type(self.fcx.node_ty(id))
+    }
+}
 
 fn regionck_expr(fcx: @fn_ctxt, e: @ast::expr) {
-    let rcx = @{fcx:fcx, mut errors_reported: 0u};
+    let rcx = rcx_({fcx:fcx, mut errors_reported: 0u});
     let v = regionck_visitor();
-    v.visit_expr(e, rcx, v);
+    v.visit_expr(e, @rcx, v);
 }
 
 fn regionck_fn(fcx: @fn_ctxt,
                _decl: ast::fn_decl,
                blk: ast::blk) {
-    let rcx = @{fcx:fcx, mut errors_reported: 0u};
+    let rcx = rcx_({fcx:fcx, mut errors_reported: 0u});
     let v = regionck_visitor();
-    v.visit_block(blk, rcx, v);
+    v.visit_block(blk, @rcx, v);
 }
 
 fn regionck_visitor() -> rvt {
@@ -49,11 +85,11 @@ fn regionck_visitor() -> rvt {
                    with *visit::default_visitor()})
 }
 
-fn visit_item(_item: @ast::item, &&_rcx: rcx, _v: rvt) {
+fn visit_item(_item: @ast::item, &&_rcx: @rcx, _v: rvt) {
     // Ignore items
 }
 
-fn visit_local(l: @ast::local, &&rcx: rcx, v: rvt) {
+fn visit_local(l: @ast::local, &&rcx: @rcx, v: rvt) {
     let e = rcx.errors_reported;
     v.visit_pat(l.node.pat, rcx, v);
     if e != rcx.errors_reported {
@@ -66,7 +102,7 @@ fn visit_local(l: @ast::local, &&rcx: rcx, v: rvt) {
     }
 }
 
-fn visit_pat(p: @ast::pat, &&rcx: rcx, v: rvt) {
+fn visit_pat(p: @ast::pat, &&rcx: @rcx, v: rvt) {
     let fcx = rcx.fcx;
     alt p.node {
       ast::pat_ident(path, _)
@@ -80,11 +116,11 @@ fn visit_pat(p: @ast::pat, &&rcx: rcx, v: rvt) {
     visit::visit_pat(p, rcx, v);
 }
 
-fn visit_block(b: ast::blk, &&rcx: rcx, v: rvt) {
+fn visit_block(b: ast::blk, &&rcx: @rcx, v: rvt) {
     visit::visit_block(b, rcx, v);
 }
 
-fn visit_expr(e: @ast::expr, &&rcx: rcx, v: rvt) {
+fn visit_expr(e: @ast::expr, &&rcx: @rcx, v: rvt) {
     #debug["visit_expr(e=%s)", pprust::expr_to_str(e)];
 
     alt e.node {
@@ -99,6 +135,41 @@ fn visit_expr(e: @ast::expr, &&rcx: rcx, v: rvt) {
           _ { }
         }
       }
+
+      ast::expr_cast(source, _) {
+        // Determine if we are casting `source` to an iface instance.
+        // If so, we have to be sure that the type of the source obeys
+        // the iface's region bound.
+        //
+        // Note: there is a subtle point here concerning type
+        // parameters.  It is possible that the type of `source`
+        // contains type parameters, which in turn may contain regions
+        // that are not visible to us (only the caller knows about
+        // them).  The kind checker is ultimately responsible for
+        // guaranteeing region safety in that particular case.  There
+        // is an extensive comment on the function
+        // check_cast_for_escaping_regions() in kind.rs explaining how
+        // it goes about doing that.
+        alt rcx.resolve_node_type(e.id) {
+          result::err(_) => { ret; /* typeck will fail anyhow */ }
+          result::ok(target_ty) => {
+            alt ty::get(target_ty).struct {
+              ty::ty_trait(_, substs) {
+                let iface_region = alt substs.self_r {
+                  some(r) => {r}
+                  none => {ty::re_static}
+                };
+                let source_ty = rcx.fcx.expr_ty(source);
+                constrain_regions_in_type(rcx, iface_region,
+                                          e.span, source_ty);
+              }
+              _ { }
+            }
+          }
+        };
+
+      }
+
       _ { }
     }
 
@@ -106,7 +177,7 @@ fn visit_expr(e: @ast::expr, &&rcx: rcx, v: rvt) {
     visit::visit_expr(e, rcx, v);
 }
 
-fn visit_stmt(s: @ast::stmt, &&rcx: rcx, v: rvt) {
+fn visit_stmt(s: @ast::stmt, &&rcx: @rcx, v: rvt) {
     visit::visit_stmt(s, rcx, v);
 }
 
@@ -114,37 +185,13 @@ fn visit_stmt(s: @ast::stmt, &&rcx: rcx, v: rvt) {
 // references a region that is not in scope for that node.  Returns
 // false if an error is reported; this is used to cause us to cut off
 // region checking for that subtree to avoid reporting tons of errors.
-fn visit_node(id: ast::node_id, span: span, rcx: rcx) -> bool {
+fn visit_node(id: ast::node_id, span: span, rcx: @rcx) -> bool {
     let fcx = rcx.fcx;
 
     // Try to resolve the type.  If we encounter an error, then typeck
     // is going to fail anyway, so just stop here and let typeck
     // report errors later on in the writeback phase.
-    //
+    let ty = alt rcx.resolve_node_type(id) {
-    // Note one important point: we do not attempt to resolve *region
-    // variables* here.  This is because regionck is essentially adding
-    // constraints to those region variables and so may yet influence
-    // how they are resolved.
-    //
-    // Consider this silly example:
-    //
-    //     fn borrow(x: &int) -> &int {x}
-    //     fn foo(x: @int) -> int {  /* block: B */
-    //         let b = borrow(x);    /* region: <R0> */
-    //         *b
-    //     }
-    //
-    // Here, the region of `b` will be `<R0>`.  `<R0>` is constrainted
-    // to be some subregion of the block B and some superregion of
-    // the call.  If we forced it now, we'd choose the smaller region
-    // (the call).  But that would make the *b illegal.  Since we don't
-    // resolve, the type of b will be `&<R0>.int` and then `*b` will require
-    // that `<R0>` be bigger than the let and the `*b` expression, so we
-    // will effectively resolve `<R0>` to be the block B.
-    let ty0 = fcx.node_ty(id);
-    let ty = alt resolve_type(fcx.infcx, ty0,
-                              (resolve_all | force_all) -
-                              (resolve_rvar | force_rvar)) {
       result::err(_) { ret true; }
       result::ok(ty) { ty }
     };
@@ -153,21 +200,29 @@ fn visit_node(id: ast::node_id, span: span, rcx: rcx) -> bool {
     let tcx = fcx.ccx.tcx;
     let encl_region = ty::encl_region(tcx, id);
 
-    #debug["visit_node(ty=%s, id=%d, encl_region=%s, ty0=%s)",
+    #debug["visit_node(ty=%s, id=%d, encl_region=%s)",
            ppaux::ty_to_str(tcx, ty),
            id,
-           ppaux::region_to_str(tcx, encl_region),
+           ppaux::region_to_str(tcx, encl_region)];
-           ppaux::ty_to_str(tcx, ty0)];
 
     // Otherwise, look at the type and see if it is a region pointer.
+    ret constrain_regions_in_type(rcx, encl_region, span, ty);
+}
+
+fn constrain_regions_in_type(
+    rcx: @rcx,
+    encl_region: ty::region,
+    span: span,
+    ty: ty::t) -> bool {
+
     let e = rcx.errors_reported;
     ty::walk_regions_and_ty(
-        tcx, ty,
+        rcx.fcx.ccx.tcx, ty,
         |r| constrain_region(rcx, encl_region, span, r),
         |t| ty::type_has_regions(t));
     ret (e == rcx.errors_reported);
 
-    fn constrain_region(rcx: rcx,
+    fn constrain_region(rcx: @rcx,
                         encl_region: ty::region,
                         span: span,
                         region: ty::region) {

src/rustc/middle/typeck/check/vtable.rs

@@ -64,7 +64,7 @@ fn lookup_vtable(fcx: @fn_ctxt, isc: resolve::iscopes, sp: span,
     };
     let ty = fixup_ty(fcx, sp, ty);
     alt ty::get(ty).struct {
-      ty::ty_param(n, did) {
+      ty::ty_param({idx: n, def_id: did}) {
         let mut n_bound = 0u;
         for vec::each(*tcx.ty_param_bounds.get(did.node)) |bound| {
             alt bound {

src/rustc/middle/typeck/collect.rs

@@ -69,7 +69,9 @@ fn collect_item_types(ccx: @crate_ctxt, crate: @ast::crate) {
 }
 
 impl methods for @crate_ctxt {
-    fn to_ty<RS: region_scope copy>(rs: RS, ast_ty: @ast::ty) -> ty::t {
+    fn to_ty<RS: region_scope copy owned>(
+        rs: RS, ast_ty: @ast::ty) -> ty::t {
+
         ast_ty_to_ty(self, rs, ast_ty)
     }
 }

src/rustc/middle/typeck/infer.rs

@@ -195,7 +195,7 @@ export resolve_type, resolve_region;
 export resolve_borrowings;
 export methods; // for infer_ctxt
 export unify_methods; // for infer_ctxt
-export fixup_err, fixup_err_to_str;
+export fres, fixup_err, fixup_err_to_str;
 export assignment;
 export root, to_str;
 export int_ty_set_all;
@@ -1789,7 +1789,7 @@ fn super_tys<C:combine>(
         }
       }
 
-      (ty::ty_param(a_n, _), ty::ty_param(b_n, _)) if a_n == b_n {
+      (ty::ty_param(a_p), ty::ty_param(b_p)) if a_p.idx == b_p.idx {
         ok(a)
       }
 

src/rustc/middle/typeck/rscope.rs

@@ -38,7 +38,7 @@ impl of region_scope for type_rscope {
 }
 
 enum anon_rscope = {anon: ty::region, base: region_scope};
-fn in_anon_rscope<RS: region_scope copy>(self: RS, r: ty::region)
+fn in_anon_rscope<RS: region_scope copy owned>(self: RS, r: ty::region)
     -> @anon_rscope {
     @anon_rscope({anon: r, base: self as region_scope})
 }
@@ -52,7 +52,8 @@ impl of region_scope for @anon_rscope {
 }
 
 enum binding_rscope = {base: region_scope};
-fn in_binding_rscope<RS: region_scope copy>(self: RS) -> @binding_rscope {
+fn in_binding_rscope<RS: region_scope copy owned>(self: RS)
+    -> @binding_rscope {
     let base = self as region_scope;
     @binding_rscope({base: base})
 }

src/rustc/util/ppaux.rs

@@ -216,7 +216,7 @@ fn ty_to_str(cx: ctxt, typ: t) -> ~str {
       }
       ty_var(v) { v.to_str() }
       ty_var_integral(v) { v.to_str() }
-      ty_param(id, _) {
+      ty_param({idx: id, _}) {
         ~"'" + str::from_bytes(~[('a' as u8) + (id as u8)])
       }
       ty_self { ~"self" }

src/test/bench/shootout-binarytrees.rs

@@ -13,7 +13,7 @@ fn item_check(t: &tree) -> int {
     }
 }
 
-fn bottom_up_tree(arena: &a.arena::arena, item: int, depth: int) -> &a.tree {
+fn bottom_up_tree(arena: &arena::arena, item: int, depth: int) -> &tree {
     if depth > 0 {
         ret new(*arena) node(bottom_up_tree(arena, 2 * item - 1, depth - 1),
                              bottom_up_tree(arena, 2 * item, depth - 1),

src/test/compile-fail/block-arg-used-as-lambda-with-illegal-cap.rs

@@ -3,7 +3,7 @@ fn to_lambda1(f: fn@(uint) -> uint) -> fn@(uint) -> uint {
 }
 
 fn to_lambda2(b: fn(uint) -> uint) -> fn@(uint) -> uint {
-    ret to_lambda1({|x| b(x)}); //~ ERROR not an owned value
+    ret to_lambda1({|x| b(x)}); //~ ERROR value may contain borrowed pointers
 }
 
 fn main() {

src/test/compile-fail/kindck-owned-trait-contains.rs

@@ -0,0 +1,20 @@
+iface repeat<A> { fn get() -> A; }
+
+impl<A:copy> of repeat<A> for @A {
+    fn get() -> A { *self }
+}
+
+fn repeater<A:copy>(v: @A) -> repeat<A> {
+    // Note: owned kind is not necessary as A appears in the iface type
+    v as repeat::<A> // No
+}
+
+fn main() {
+    // Here, an error results as the type of y is inferred to
+    // repeater<&lt/3> where lt is the block.
+    let y = { //~ ERROR reference is not valid outside of its lifetime
+        let x = &3;
+        repeater(@x)
+    };
+    assert 3 == *(y.get()); //~ ERROR reference is not valid outside of its lifetime
+}

src/test/compile-fail/kindck-owned-trait-scoped.rs

@@ -0,0 +1,35 @@
+// A dummy iface/impl that work close over any type.  The iface will
+// be parameterized by a region due to the &self/int constraint.
+
+iface foo {
+    fn foo(i: &self/int) -> int;
+}
+
+impl<T:copy> of foo for T {
+    fn foo(i: &self/int) -> int {*i}
+}
+
+fn to_foo<T:copy>(t: T) {
+    // This version is ok because, although T may contain borrowed
+    // pointers, it never escapes the fn body.  We know this because
+    // the type of foo includes a region which will be resolved to
+    // the fn body itself.
+    let v = &3;
+    let x = {f:t} as foo;
+    assert x.foo(v) == 3;
+}
+
+fn to_foo_2<T:copy>(t: T) -> foo {
+    // Not OK---T may contain borrowed ptrs and it is going to escape
+    // as part of the returned foo value
+    {f:t} as foo //~ ERROR value may contain borrowed pointers; use `owned` bound
+}
+
+fn to_foo_3<T:copy owned>(t: T) -> foo {
+    // OK---T may escape as part of the returned foo value, but it is
+    // owned and hence does not contain borrowed ptrs
+    {f:t} as foo
+}
+
+fn main() {
+}

src/test/compile-fail/kindck-owned-trait.rs

@@ -0,0 +1,11 @@
+iface foo { fn foo(); }
+
+fn to_foo<T: copy foo>(t: T) -> foo {
+    t as foo //~ ERROR value may contain borrowed pointers; use `owned` bound
+}
+
+fn to_foo2<T: copy foo owned>(t: T) -> foo {
+    t as foo
+}
+
+fn main() {}

src/test/compile-fail/kindck-owned.rs

@@ -1,5 +1,5 @@
 fn copy1<T: copy>(t: T) -> fn@() -> T {
-    fn@() -> T { t } //~ ERROR not an owned value
+    fn@() -> T { t } //~ ERROR value may contain borrowed pointers
 }
 
 fn copy2<T: copy owned>(t: T) -> fn@() -> T {
@@ -8,12 +8,12 @@ fn copy2<T: copy owned>(t: T) -> fn@() -> T {
 
 fn main() {
     let x = &3;
-    copy2(&x); //~ ERROR instantiating a type parameter with an incompatible type
+    copy2(&x); //~ ERROR missing `owned`
 
     copy2(@3);
-    copy2(@&x); //~ ERROR instantiating a type parameter with an incompatible type
+    copy2(@&x); //~ ERROR missing `owned`
 
     copy2(fn@() {});
     copy2(fn~() {}); //~ WARNING instantiating copy type parameter with a not implicitly copyable type
-    copy2(fn&() {}); //~ ERROR instantiating a type parameter with an incompatible type
+    copy2(fn&() {}); //~ ERROR missing `copy owned`
 }

src/test/run-pass/borrowck-borrow-from-at-vec.rs

@@ -0,0 +1,10 @@
+fn sum_slice(x: &[int]) -> int {
+    let mut sum = 0;
+    for x.each |i| { sum += i; }
+    ret sum;
+}
+
+fn main() {
+    let x = @[1, 2, 3];
+    assert sum_slice(x) == 6;
+}

src/test/run-pass/issue-2734.rs

@@ -1,7 +1,7 @@
 iface hax { } 
 impl <A> of hax for A { } 
 
-fn perform_hax<T>(x: @T) -> hax {
+fn perform_hax<T: owned>(x: @T) -> hax {
     x as hax 
 }
 

src/test/run-pass/issue-2735.rs

@@ -1,7 +1,7 @@
 iface hax { } 
 impl <A> of hax for A { } 
 
-fn perform_hax<T>(x: @T) -> hax {
+fn perform_hax<T: owned>(x: @T) -> hax {
     x as hax 
 }
 

src/test/run-pass/kindck-owned-trait-contains-1.rs

@@ -0,0 +1,16 @@
+iface repeat<A> { fn get() -> A; }
+
+impl<A:copy> of repeat<A> for @A {
+    fn get() -> A { *self }
+}
+
+fn repeater<A:copy>(v: @A) -> repeat<A> {
+    // Note: owned kind is not necessary as A appears in the iface type
+    v as repeat::<A> // No
+}
+
+fn main() {
+    let x = &3;
+    let y = repeater(@x);
+    assert *x == *(y.get());
+}

src/test/run-pass/reflect-visit-data.rs

@@ -230,9 +230,9 @@ impl ptr_visitor<V: ty_visitor movable_ptr>
     }
 
     fn visit_rptr(mtbl: uint, inner: *tydesc) -> bool {
-        self.align_to::<&static.u8>();
+        self.align_to::<&static/u8>();
         if ! self.inner.visit_rptr(mtbl, inner) { ret false; }
-        self.bump_past::<&static.u8>();
+        self.bump_past::<&static/u8>();
         true
     }
 
@@ -268,9 +268,9 @@ impl ptr_visitor<V: ty_visitor movable_ptr>
     }
 
     fn visit_evec_slice(mtbl: uint, inner: *tydesc) -> bool {
-        self.align_to::<&static.[u8]>();
+        self.align_to::<&static/[u8]>();
         if ! self.inner.visit_evec_slice(mtbl, inner) { ret false; }
-        self.bump_past::<&static.[u8]>();
+        self.bump_past::<&static/[u8]>();
         true
     }
 
@@ -427,9 +427,9 @@ impl ptr_visitor<V: ty_visitor movable_ptr>
     }
 
     fn visit_self() -> bool {
-        self.align_to::<&static.u8>();
+        self.align_to::<&static/u8>();
         if ! self.inner.visit_self() { ret false; }
-        self.align_to::<&static.u8>();
+        self.align_to::<&static/u8>();
         true
     }
 

src/test/run-pass/regions-addr-of-ret.rs

@@ -1,4 +1,4 @@
-fn f(x : &a.int) -> &a.int {
+fn f(x : &a/int) -> &a/int {
     ret &*x;
 }
 

src/test/run-pass/regions-bot.rs

@@ -1,6 +1,6 @@
 // A very limited test of the "bottom" region
 
-fn produce_static<T>() -> &static.T { fail; }
+fn produce_static<T>() -> &static/T { fail; }
 
 fn foo<T>(x: &T) -> &uint { produce_static() }
 

src/test/run-pass/regions-fn-subtyping.rs

@@ -8,14 +8,14 @@ fn ok(f: fn@(x: &uint)) {
     // f's type should be a subtype of g's type), because f can be
     // used in any context that expects g's type.  But this currently
     // fails.
-    let mut g: fn@(y: &r.uint) = fn@(x: &r.uint) { };
+    let mut g: fn@(y: &r/uint) = fn@(x: &r/uint) { };
     g = f;
 }
 
 // This version is the same as above, except that here, g's type is
 // inferred.
 fn ok_inferred(f: fn@(x: &uint)) {
-    let mut g = fn@(x: &r.uint) { };
+    let mut g = fn@(x: &r/uint) { };
     g = f;
 }
 

src/test/run-pass/regions-iface.rs

@@ -19,5 +19,8 @@ fn get_v(gc: get_ctxt) -> uint {
 fn main() {
     let ctxt = { v: 22u };
     let hc = { c: &ctxt };
-    assert get_v(hc as get_ctxt) == 22u;
+
+    // This no longer works, interestingly, due to the ownership
+    // requirement.  Perhaps this ownership requirement is too strict.
+    // assert get_v(hc as get_ctxt) == 22u;
 }

src/test/run-pass/regions-mock-trans.rs

@@ -15,12 +15,12 @@ type ccx = {
     x: int
 };
 
-fn alloc(_bcx : &a.arena) -> &a.bcx unsafe {
+fn alloc(_bcx : &arena) -> &bcx unsafe {
     ret unsafe::reinterpret_cast(
         libc::malloc(sys::size_of::<bcx/&blk>() as libc::size_t));
 }
 
-fn h(bcx : &a.bcx) -> &a.bcx {
+fn h(bcx : &bcx) -> &bcx {
     ret alloc(bcx.fcx.arena);
 }
 

src/test/run-pass/regions-params.rs

@@ -1,4 +1,4 @@
-fn region_identity(x: &r.uint) -> &r.uint { x }
+fn region_identity(x: &uint) -> &uint { x }
 
 fn apply<T>(t: T, f: fn(T) -> T) -> T { f(t) }