auto merge of #5676 : nikomatsakis/rust/issue-4183-trait_ref, r=nikomatsakis

These are a number of incremental steps towards #4183 and #4646.

9 files changed, 57 insertions, 39 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 2e7ae4c537a..ec77b54a853 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -144,7 +144,7 @@ pub static crate_node_id: node_id = 0;
 // the "special" built-in traits (see middle::lang_items) and
 // detects Copy, Send, Owned, and Const.
 pub enum TyParamBound {
-    TraitTyParamBound(@Ty),
+    TraitTyParamBound(@trait_ref),
     RegionTyParamBound
 }
 
@@ -194,6 +194,7 @@ pub enum def {
     def_local(node_id, bool /* is_mutbl */),
     def_variant(def_id /* enum */, def_id /* variant */),
     def_ty(def_id),
+    def_trait(def_id),
     def_prim_ty(prim_ty),
     def_ty_param(def_id, uint),
     def_binding(node_id, binding_mode),
@@ -1185,6 +1186,15 @@ pub struct trait_ref {
 #[deriving(Eq)]
 pub enum visibility { public, private, inherited }
 
+impl visibility {
+    fn inherit_from(&self, parent_visibility: visibility) -> visibility {
+        match self {
+            &inherited => parent_visibility,
+            &public | &private => *self
+        }
+    }
+}
+
 #[auto_encode]
 #[auto_decode]
 #[deriving(Eq)]
diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs
index 208ed1e35fe..c7227fa1768 100644
--- a/src/libsyntax/ast_util.rs
+++ b/src/libsyntax/ast_util.rs
@@ -61,7 +61,7 @@ pub fn def_id_of_def(d: def) -> def_id {
       def_fn(id, _) | def_static_method(id, _, _) | def_mod(id) |
       def_foreign_mod(id) | def_const(id) |
       def_variant(_, id) | def_ty(id) | def_ty_param(id, _) |
-      def_use(id) | def_struct(id) => {
+      def_use(id) | def_struct(id) | def_trait(id) => {
         id
       }
       def_arg(id, _, _) | def_local(id, _) | def_self(id, _) | def_self_ty(id)
diff --git a/src/libsyntax/ext/auto_encode.rs b/src/libsyntax/ext/auto_encode.rs
index d25792355a7..97bc89248ac 100644
--- a/src/libsyntax/ext/auto_encode.rs
+++ b/src/libsyntax/ext/auto_encode.rs
@@ -222,15 +222,14 @@ pub fn expand_auto_decode(
 priv impl @ext_ctxt {
     fn bind_path(
         &self,
-        span: span,
+        _span: span,
         ident: ast::ident,
         path: @ast::path,
         bounds: @OptVec<ast::TyParamBound>
     ) -> ast::TyParam {
-        let bound = ast::TraitTyParamBound(@ast::Ty {
-            id: self.next_id(),
-            node: ast::ty_path(path, self.next_id()),
-            span: span,
+        let bound = ast::TraitTyParamBound(@ast::trait_ref {
+            ref_id: self.next_id(),
+            path: path
         });
 
         ast::TyParam {
@@ -466,10 +465,9 @@ fn mk_impl(
     // All the type parameters need to bound to the trait.
     let mut impl_tps = opt_vec::with(ty_param);
     for generics.ty_params.each |tp| {
-        let t_bound = ast::TraitTyParamBound(@ast::Ty {
-            id: cx.next_id(),
-            node: ast::ty_path(path, cx.next_id()),
-            span: span,
+        let t_bound = ast::TraitTyParamBound(@ast::trait_ref {
+            path: path,
+            ref_id: cx.next_id(),
         });
 
         impl_tps.push(ast::TyParam {
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 9499f95f0e7..43f0c9edcb9 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -337,6 +337,17 @@ pub fn mk_ty_path_global(cx: @ext_ctxt,
     let ty = @ast::Ty { id: cx.next_id(), node: ty, span: span };
     ty
 }
+pub fn mk_trait_ref_global(cx: @ext_ctxt,
+                           span: span,
+                           +idents: ~[ ast::ident ])
+    -> @ast::trait_ref
+{
+    let path = build::mk_raw_path_global(span, idents);
+    @ast::trait_ref {
+        path: path,
+        ref_id: cx.next_id()
+    }
+}
 pub fn mk_simple_ty_path(cx: @ext_ctxt,
                          span: span,
                          ident: ast::ident)
diff --git a/src/libsyntax/ext/deriving/mod.rs b/src/libsyntax/ext/deriving/mod.rs
index 18ebceaeb43..ccd9a33757d 100644
--- a/src/libsyntax/ext/deriving/mod.rs
+++ b/src/libsyntax/ext/deriving/mod.rs
@@ -177,9 +177,9 @@ pub fn create_derived_impl(cx: @ext_ctxt,
 
     // Create the type parameters.
     let impl_ty_params = generics.ty_params.map(|ty_param| {
-        let bound = build::mk_ty_path_global(cx,
-                                             span,
-                                             trait_path.map(|x| *x));
+        let bound = build::mk_trait_ref_global(cx,
+                                               span,
+                                               trait_path.map(|x| *x));
         let bounds = @opt_vec::with(TraitTyParamBound(bound));
         build::mk_ty_param(cx, ty_param.ident, bounds)
     });
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 0a473b1cebe..5aa51c262e1 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -134,7 +134,7 @@ pub fn fold_fn_decl(decl: &ast::fn_decl, fld: @ast_fold) -> ast::fn_decl {
 
 fn fold_ty_param_bound(tpb: &TyParamBound, fld: @ast_fold) -> TyParamBound {
     match *tpb {
-        TraitTyParamBound(ty) => TraitTyParamBound(fld.fold_ty(ty)),
+        TraitTyParamBound(ty) => TraitTyParamBound(fold_trait_ref(ty, fld)),
         RegionTyParamBound => RegionTyParamBound
     }
 }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 1d780c9b806..3a3597828cd 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -2750,8 +2750,8 @@ pub impl Parser {
                     self.bump();
                 }
                 token::MOD_SEP | token::IDENT(*) => {
-                    let maybe_bound = match *self.token {
-                        token::MOD_SEP => None,
+                    let obsolete_bound = match *self.token {
+                        token::MOD_SEP => false,
                         token::IDENT(copy sid, _) => {
                             match *self.id_to_str(sid) {
                                 ~"send" |
@@ -2761,27 +2761,18 @@ pub impl Parser {
                                     self.obsolete(
                                         *self.span,
                                         ObsoleteLowerCaseKindBounds);
-
-                                    // Bogus value, but doesn't matter, since
-                                    // is an error
-                                    Some(TraitTyParamBound(
-                                        self.mk_ty_path(sid)))
+                                    self.bump();
+                                    true
                                 }
-                                _ => None
+                                _ => false
                             }
                         }
                         _ => fail!()
                     };
 
-                    match maybe_bound {
-                        Some(bound) => {
-                            self.bump();
-                            result.push(bound);
-                        }
-                        None => {
-                            let ty = self.parse_ty(true);
-                            result.push(TraitTyParamBound(ty));
-                        }
+                    if !obsolete_bound {
+                        let tref = self.parse_trait_ref();
+                        result.push(TraitTyParamBound(tref));
                     }
                 }
                 _ => break,
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 0c79cbca039..20fc99baf21 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -562,7 +562,7 @@ pub fn print_item(s: @ps, &&item: @ast::item) {
 
         match opt_trait {
             Some(t) => {
-                print_path(s, t.path, false);
+                print_trait_ref(s, t);
                 space(s.s);
                 word_space(s, ~"for");
             }
@@ -619,6 +619,10 @@ pub fn print_item(s: @ps, &&item: @ast::item) {
     (s.ann.post)(ann_node);
 }
 
+fn print_trait_ref(s: @ps, t: &ast::trait_ref) {
+    print_path(s, t.path, false);
+}
+
 pub fn print_enum_def(s: @ps, enum_definition: ast::enum_def,
                       generics: &ast::Generics, ident: ast::ident,
                       span: codemap::span, visibility: ast::visibility) {
@@ -1744,7 +1748,7 @@ pub fn print_bounds(s: @ps, bounds: @OptVec<ast::TyParamBound>) {
             }
 
             match *bound {
-                TraitTyParamBound(ty) => print_type(s, ty),
+                TraitTyParamBound(tref) => print_trait_ref(s, tref),
                 RegionTyParamBound => word(s.s, ~"'static"),
             }
         }
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index a994f2b5b22..b20c5eeee1f 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -147,6 +147,10 @@ pub fn visit_local<E>(loc: @local, e: E, v: vt<E>) {
     }
 }
 
+fn visit_trait_ref<E>(tref: @ast::trait_ref, e: E, v: vt<E>) {
+    visit_path(tref.path, e, v);
+}
+
 pub fn visit_item<E>(i: @item, e: E, v: vt<E>) {
     match i.node {
         item_const(t, ex) => {
@@ -189,9 +193,9 @@ pub fn visit_item<E>(i: @item, e: E, v: vt<E>) {
         }
         item_impl(ref tps, ref traits, ty, ref methods) => {
             (v.visit_generics)(tps, e, v);
-            for traits.each |p| {
-                visit_path(p.path, e, v);
-        }
+            for traits.each |&p| {
+                visit_trait_ref(p, e, v);
+            }
             (v.visit_ty)(ty, e, v);
             for methods.each |m| {
                 visit_method_helper(*m, e, v)
@@ -327,8 +331,8 @@ pub fn visit_ty_param_bounds<E>(bounds: @OptVec<TyParamBound>,
                                 e: E, v: vt<E>) {
     for bounds.each |bound| {
         match *bound {
-            TraitTyParamBound(ty) => (v.visit_ty)(ty, e, v),
-            RegionTyParamBound => ()
+            TraitTyParamBound(ty) => visit_trait_ref(ty, e, v),
+            RegionTyParamBound => {}
         }
     }
 }