rustc: Implement ~Trait

src/rustc/middle/borrowck.rs

@@ -594,7 +594,7 @@ impl borrowck_ctxt {
 // mutable structure.
 fn inherent_mutability(ck: comp_kind) -> mutability {
     match ck {
-      comp_tuple | comp_variant(_)        => m_imm,
-      comp_field(_, m) | comp_index(_, m) => m
+      comp_tuple | comp_anon_field | comp_variant(_) => m_imm,
+      comp_field(_, m) | comp_index(_, m)            => m
     }
 }

src/rustc/middle/borrowck/gather_loans.rs

@@ -441,7 +441,8 @@ impl gather_loan_ctxt {
                   alt_id: ast::node_id) {
         do self.bccx.cat_pattern(discr_cmt, root_pat) |cmt, pat| {
             match pat.node {
-              ast::pat_ident(bm, _, _) if !self.pat_is_variant(pat) => {
+              ast::pat_ident(bm, _, _)
+                    if !self.pat_is_variant_or_struct(pat) => {
                 match bm {
                   ast::bind_by_value | ast::bind_by_move => {
                     // copying does not borrow anything, so no check
@@ -492,8 +493,8 @@ impl gather_loan_ctxt {
         }
     }
 
-    fn pat_is_variant(&self, pat: @ast::pat) -> bool {
-        pat_util::pat_is_variant(self.bccx.tcx.def_map, pat)
+    fn pat_is_variant_or_struct(&self, pat: @ast::pat) -> bool {
+        pat_util::pat_is_variant_or_struct(self.bccx.tcx.def_map, pat)
     }
 }
 

src/rustc/middle/borrowck/loan.rs

@@ -116,7 +116,8 @@ impl LoanContext {
             // overwritten and the component along with it.
             self.loan_stable_comp(cmt, cmt_base, req_mutbl, m)
           }
-          cat_comp(cmt_base, comp_tuple) => {
+          cat_comp(cmt_base, comp_tuple) |
+          cat_comp(cmt_base, comp_anon_field) => {
             // As above.
             self.loan_stable_comp(cmt, cmt_base, req_mutbl, m_imm)
           }

src/rustc/middle/borrowck/preserve.rs

@@ -119,7 +119,8 @@ priv impl &preserve_ctxt {
           }
           cat_comp(cmt_base, comp_field(*)) |
           cat_comp(cmt_base, comp_index(*)) |
-          cat_comp(cmt_base, comp_tuple) => {
+          cat_comp(cmt_base, comp_tuple) |
+          cat_comp(cmt_base, comp_anon_field) => {
             // Most embedded components: if the base is stable, the
             // type never changes.
             self.preserve(cmt_base)

src/rustc/middle/check_alt.rs

@@ -355,6 +355,15 @@ fn specialize(tcx: ty::ctxt, r: ~[@pat], ctor_id: ctor, arity: uint,
             Some(vec::append(args, vec::tail(r)))
           }
           def_variant(_, _) => None,
+          def_class(*) => {
+            // XXX: Is this right? --pcw
+            let new_args;
+            match args {
+              Some(args) => new_args = args,
+              None => new_args = vec::from_elem(arity, wild())
+            }
+            Some(vec::append(new_args, vec::tail(r)))
+          }
           _ => None
         }
       }

src/rustc/middle/kind.rs

@@ -286,6 +286,7 @@ fn check_expr(e: @expr, cx: ctx, v: visit::vt<ctx>) {
         maybe_copy(cx, source, Some(("casted values must be copyable",
                                      try_adding)));
         check_cast_for_escaping_regions(cx, source, e);
+        check_kind_bounds_of_cast(cx, source, e);
       }
       expr_copy(expr) => check_copy_ex(cx, expr, false,
           Some(("explicit copy requires a copyable argument", ""))),
@@ -607,6 +608,26 @@ fn check_cast_for_escaping_regions(
     }
 }
 
+/// Ensures that values placed into a ~Trait are copyable and sendable.
+fn check_kind_bounds_of_cast(cx: ctx, source: @expr, target: @expr) {
+    let target_ty = ty::expr_ty(cx.tcx, target);
+    match ty::get(target_ty).sty {
+        ty::ty_trait(_, _, ty::vstore_uniq) => {
+            let source_ty = ty::expr_ty(cx.tcx, source);
+            let source_kind = ty::type_kind(cx.tcx, source_ty);
+            if !ty::kind_can_be_copied(source_kind) {
+                cx.tcx.sess.span_err(target.span,
+                    ~"uniquely-owned trait objects must be copyable");
+            }
+            if !ty::kind_can_be_sent(source_kind) {
+                cx.tcx.sess.span_err(target.span,
+                    ~"uniquely-owned trait objects must be sendable");
+            }
+        }
+        _ => {} // Nothing to do.
+    }
+}
+
 //
 // Local Variables:
 // mode: rust

src/rustc/middle/mem_categorization.rs

@@ -162,6 +162,8 @@ impl ptr_kind : cmp::Eq {
 // structure accessible without a dereference":
 enum comp_kind {
     comp_tuple,                  // elt in a tuple
+    comp_anon_field,             // anonymous field (in e.g.
+                                 // struct Foo(int, int);
     comp_variant(ast::def_id),   // internals to a variant of given enum
     comp_field(ast::ident,       // name of field
                ast::mutability), // declared mutability of field
@@ -178,6 +180,12 @@ impl comp_kind : cmp::Eq {
                     _ => false
                 }
             }
+            comp_anon_field => {
+                match (*other) {
+                    comp_anon_field => true,
+                    _ => false
+                }
+            }
             comp_variant(e0a) => {
                 match (*other) {
                     comp_variant(e0b) => e0a == e0b,
@@ -773,6 +781,14 @@ impl &mem_categorization_ctxt {
           ty: self.tcx.ty(elt)}
     }
 
+    fn cat_anon_struct_field<N: ast_node>(elt: N, cmt: cmt) -> cmt {
+        @{id: elt.id(), span: elt.span(),
+          cat: cat_comp(cmt, comp_anon_field),
+          lp: cmt.lp.map(|l| @lp_comp(*l, comp_anon_field)),
+          mutbl: cmt.mutbl, // imm iff in an immutable context
+          ty: self.tcx.ty(elt)}
+    }
+
     fn cat_method_ref(expr: @ast::expr, expr_ty: ty::t) -> cmt {
         @{id:expr.id, span:expr.span,
           cat:cat_special(sk_method), lp:None,
@@ -832,16 +848,26 @@ impl &mem_categorization_ctxt {
             // variant(*)
           }
           ast::pat_enum(_, Some(subpats)) => {
-            // variant(x, y, z)
-            let enum_did = match self.tcx.def_map.find(pat.id) {
-              Some(ast::def_variant(enum_did, _)) => enum_did,
-              e => tcx.sess.span_bug(pat.span,
-                                     fmt!("resolved to %?, not variant", e))
-            };
-
-            for subpats.each |subpat| {
-                let subcmt = self.cat_variant(*subpat, enum_did, cmt);
-                self.cat_pattern(subcmt, *subpat, op);
+            match self.tcx.def_map.find(pat.id) {
+                Some(ast::def_variant(enum_did, _)) => {
+                    // variant(x, y, z)
+                    for subpats.each |subpat| {
+                        let subcmt = self.cat_variant(*subpat, enum_did, cmt);
+                        self.cat_pattern(subcmt, *subpat, op);
+                    }
+                }
+                Some(ast::def_class(*)) => {
+                    for subpats.each |subpat| {
+                        let cmt_field = self.cat_anon_struct_field(*subpat,
+                                                                   cmt);
+                        self.cat_pattern(cmt_field, *subpat, op);
+                    }
+                }
+                _ => {
+                    self.tcx.sess.span_bug(
+                        pat.span,
+                        ~"enum pattern didn't resolve to enum or struct");
+                }
             }
           }
 
@@ -932,6 +958,7 @@ impl &mem_categorization_ctxt {
           comp_field(fld, _) => self.tcx.sess.str_of(fld),
           comp_index(*) => ~"[]",
           comp_tuple => ~"()",
+          comp_anon_field => ~"<anonymous field>",
           comp_variant(_) => ~"<enum>"
         }
     }
@@ -984,6 +1011,7 @@ impl &mem_categorization_ctxt {
           }
           cat_comp(_, comp_field(*)) => mut_str + ~" field",
           cat_comp(_, comp_tuple) => ~"tuple content",
+          cat_comp(_, comp_anon_field) => ~"anonymous field",
           cat_comp(_, comp_variant(_)) => ~"enum content",
           cat_comp(_, comp_index(t, _)) => {
             match ty::get(t).sty {

src/rustc/middle/pat_util.rs

@@ -7,7 +7,7 @@ use syntax::codemap::span;
 use std::map::HashMap;
 
 export pat_binding_ids, pat_bindings, pat_id_map, PatIdMap;
-export pat_is_variant, pat_is_binding_or_wild;
+export pat_is_variant_or_struct, pat_is_binding_or_wild;
 
 type PatIdMap = std::map::HashMap<ident, node_id>;
 
@@ -21,20 +21,21 @@ fn pat_id_map(dm: resolve::DefMap, pat: @pat) -> PatIdMap {
     return map;
 }
 
-fn pat_is_variant(dm: resolve::DefMap, pat: @pat) -> bool {
+fn pat_is_variant_or_struct(dm: resolve::DefMap, pat: @pat) -> bool {
     match pat.node {
-      pat_enum(_, _) => true,
-      pat_ident(_, _, None) | pat_struct(*) => match dm.find(pat.id) {
-        Some(def_variant(_, _)) => true,
+        pat_enum(_, _) | pat_ident(_, _, None) | pat_struct(*) => {
+            match dm.find(pat.id) {
+                Some(def_variant(*)) | Some(def_class(*)) => true,
+                _ => false
+            }
+        }
         _ => false
-      },
-      _ => false
     }
 }
 
 fn pat_is_binding_or_wild(dm: resolve::DefMap, pat: @pat) -> bool {
     match pat.node {
-        pat_ident(*) => !pat_is_variant(dm, pat),
+        pat_ident(*) => !pat_is_variant_or_struct(dm, pat),
         pat_wild => true,
         _ => false
     }
@@ -44,7 +45,8 @@ fn pat_bindings(dm: resolve::DefMap, pat: @pat,
                 it: fn(binding_mode, node_id, span, @path)) {
     do walk_pat(pat) |p| {
         match p.node {
-          pat_ident(binding_mode, pth, _) if !pat_is_variant(dm, p) => {
+          pat_ident(binding_mode, pth, _)
+                if !pat_is_variant_or_struct(dm, p) => {
             it(binding_mode, p.id, p.span, pth);
           }
           _ => {}

src/rustc/middle/resolve.rs

@@ -288,10 +288,10 @@ impl AllowCapturingSelfFlag : cmp::Eq {
     pure fn ne(other: &AllowCapturingSelfFlag) -> bool { !self.eq(other) }
 }
 
-enum EnumVariantOrConstResolution {
-    FoundEnumVariant(def),
+enum BareIdentifierPatternResolution {
+    FoundStructOrEnumVariant(def),
     FoundConst,
-    EnumVariantOrConstNotFound
+    BareIdentifierPatternUnresolved
 }
 
 // Specifies how duplicates should be handled when adding a child item if
@@ -4187,28 +4187,31 @@ impl Resolver {
                         if !path.global && path.idents.len() == 1u => {
 
                     // The meaning of pat_ident with no type parameters
-                    // depends on whether an enum variant with that name is in
-                    // scope. The probing lookup has to be careful not to emit
-                    // spurious errors. Only matching patterns (match) can
-                    // match nullary variants. For binding patterns (let),
-                    // matching such a variant is simply disallowed (since
-                    // it's rarely what you want).
+                    // depends on whether an enum variant or unit-like struct
+                    // with that name is in scope. The probing lookup has to
+                    // be careful not to emit spurious errors. Only matching
+                    // patterns (match) can match nullary variants or
+                    // unit-like structs. For binding patterns (let), matching
+                    // such a value is simply disallowed (since it's rarely
+                    // what you want).
 
                     let ident = path.idents[0];
 
-                    match self.resolve_enum_variant_or_const(ident) {
-                        FoundEnumVariant(def) if mode == RefutableMode => {
+                    match self.resolve_bare_identifier_pattern(ident) {
+                        FoundStructOrEnumVariant(def)
+                                if mode == RefutableMode => {
                             debug!("(resolving pattern) resolving `%s` to \
-                                    enum variant",
+                                    struct or enum variant",
                                     self.session.str_of(ident));
 
                             self.record_def(pattern.id, def);
                         }
-                        FoundEnumVariant(_) => {
+                        FoundStructOrEnumVariant(_) => {
                             self.session.span_err(pattern.span,
                                                   fmt!("declaration of `%s` \
                                                         shadows an enum \
-                                                        that's in scope",
+                                                        variant or unit-like \
+                                                        struct in scope",
                                                         self.session
                                                         .str_of(ident)));
                         }
@@ -4218,7 +4221,7 @@ impl Resolver {
                                                    conflicts with a constant \
                                                    in scope");
                         }
-                        EnumVariantOrConstNotFound => {
+                        BareIdentifierPatternUnresolved => {
                             debug!("(resolving pattern) binding `%s`",
                                    self.session.str_of(ident));
 
@@ -4286,9 +4289,10 @@ impl Resolver {
                 }
 
                 pat_ident(_, path, _) | pat_enum(path, _) => {
-                    // These two must be enum variants.
+                    // These two must be enum variants or structs.
                     match self.resolve_path(path, ValueNS, false, visitor) {
-                        Some(def @ def_variant(*)) => {
+                        Some(def @ def_variant(*)) |
+                                Some(def @ def_class(*)) => {
                             self.record_def(pattern.id, def);
                         }
                         Some(_) => {
@@ -4348,13 +4352,11 @@ impl Resolver {
         }
     }
 
-    fn resolve_enum_variant_or_const(name: ident)
-                                  -> EnumVariantOrConstResolution {
-
+    fn resolve_bare_identifier_pattern(name: ident)
+                                    -> BareIdentifierPatternResolution {
         match self.resolve_item_in_lexical_scope(self.current_module,
-                                               name,
-                                               ValueNS) {
-
+                                                 name,
+                                                 ValueNS) {
             Success(target) => {
                 match target.bindings.value_def {
                     None => {
@@ -4363,14 +4365,14 @@ impl Resolver {
                     }
                     Some(def) => {
                         match def.def {
-                            def @ def_variant(*) => {
-                                return FoundEnumVariant(def);
+                            def @ def_variant(*) | def @ def_class(*) => {
+                                return FoundStructOrEnumVariant(def);
                             }
                             def_const(*) => {
                                 return FoundConst;
                             }
                             _ => {
-                                return EnumVariantOrConstNotFound;
+                                return BareIdentifierPatternUnresolved;
                             }
                         }
                     }
@@ -4382,7 +4384,7 @@ impl Resolver {
             }
 
             Failed => {
-                return EnumVariantOrConstNotFound;
+                return BareIdentifierPatternUnresolved;
             }
         }
     }