librustc: Require the #[derivable] attribute, remove the significance of "impl Foo : Bar;", and allow only a subset of methods in a trait to be derived. r=brson

7 files changed, 21 insertions, 34 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index dd90dfee683..148600d8d21 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1517,7 +1517,7 @@ enum item_ {
     item_impl(~[ty_param],
               Option<@trait_ref>, /* (optional) trait this impl implements */
               @Ty, /* self */
-              Option<~[@method]>),
+              ~[@method]),
     item_mac(mac),
 }
 
diff --git a/src/libsyntax/ast_map.rs b/src/libsyntax/ast_map.rs
index c2e255cad14..0d7b1f1e5c4 100644
--- a/src/libsyntax/ast_map.rs
+++ b/src/libsyntax/ast_map.rs
@@ -203,12 +203,10 @@ fn map_item(i: @item, cx: ctx, v: vt) {
     let item_path = @/* FIXME (#2543) */ copy cx.path;
     cx.map.insert(i.id, node_item(i, item_path));
     match i.node {
-      item_impl(_, _, _, ms_opt) => {
+      item_impl(_, _, _, ms) => {
         let impl_did = ast_util::local_def(i.id);
-        for ms_opt.each |ms| {
-            for ms.each |m| {
-                map_method(impl_did, extend(cx, i.ident), *m, cx);
-            }
+        for ms.each |m| {
+            map_method(impl_did, extend(cx, i.ident), *m, cx);
         }
       }
       item_enum(enum_definition, _) => {
diff --git a/src/libsyntax/ext/auto_serialize.rs b/src/libsyntax/ext/auto_serialize.rs
index 39e94291d8b..f9fece0b5cb 100644
--- a/src/libsyntax/ext/auto_serialize.rs
+++ b/src/libsyntax/ext/auto_serialize.rs
@@ -398,7 +398,7 @@ fn mk_impl(
         ident: ast::token::special_idents::clownshoes_extensions,
         attrs: ~[],
         id: cx.next_id(),
-        node: ast::item_impl(trait_tps, opt_trait, ty, Some(~[f(ty)])),
+        node: ast::item_impl(trait_tps, opt_trait, ty, ~[f(ty)]),
         vis: ast::public,
         span: span,
     }
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 8609124126c..4d51ecded01 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -249,13 +249,11 @@ fn noop_fold_item_underscore(i: item_, fld: ast_fold) -> item_ {
             let struct_def = fold_struct_def(struct_def, fld);
               item_class(struct_def, /* FIXME (#2543) */ copy typms)
           }
-          item_impl(tps, ifce, ty, ref methods_opt) => {
+          item_impl(tps, ifce, ty, ref methods) => {
               item_impl(fold_ty_params(tps, fld),
                         ifce.map(|p| fold_trait_ref(*p, fld)),
                         fld.fold_ty(ty),
-                        option::map(methods_opt,
-                                    |methods| vec::map(
-                                        *methods, |x| fld.fold_method(*x))))
+                        vec::map(*methods, |x| fld.fold_method(*x)))
           }
           item_trait(tps, traits, methods) => {
               let methods = do methods.map |method| {
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index c5f3b1b5306..49c3d38ce55 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -2687,19 +2687,15 @@ impl Parser {
             None
         };
 
-        let meths_opt;
-        if self.eat(token::SEMI) {
-            meths_opt = None;
-        } else {
-            let mut meths = ~[];
+        let mut meths = ~[];
+        if !self.eat(token::SEMI) {
             self.expect(token::LBRACE);
             while !self.eat(token::RBRACE) {
                 meths.push(self.parse_method());
             }
-            meths_opt = Some(move meths);
         }
 
-        (ident, item_impl(tps, opt_trait, ty, meths_opt), None)
+        (ident, item_impl(tps, opt_trait, ty, meths), None)
     }
 
     // Instantiates ident <i> with references to <typarams> as arguments.
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 09cc9ad0232..267f0e7d5f2 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -520,7 +520,7 @@ fn print_item(s: ps, &&item: @ast::item) {
           print_struct(s, struct_def, tps, item.ident, item.span);
       }
 
-      ast::item_impl(tps, opt_trait, ty, methods_opt) => {
+      ast::item_impl(tps, opt_trait, ty, methods) => {
         head(s, visibility_qualified(item.vis, ~"impl"));
         if tps.is_not_empty() {
             print_type_params(s, tps);
@@ -537,17 +537,14 @@ fn print_item(s: ps, &&item: @ast::item) {
         };
         space(s.s);
 
-        match methods_opt {
-            None => {
-                word(s.s, ~";");
-            }
-            Some(methods) => {
-                bopen(s);
-                for methods.each |meth| {
-                   print_method(s, *meth);
-                }
-                bclose(s, item.span);
+        if methods.len() == 0 {
+            word(s.s, ~";");
+        } else {
+            bopen(s);
+            for methods.each |meth| {
+               print_method(s, *meth);
             }
+            bclose(s, item.span);
         }
       }
       ast::item_trait(tps, traits, methods) => {
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 42b869b6c34..3bc8c7b9420 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -142,16 +142,14 @@ fn visit_item<E>(i: @item, e: E, v: vt<E>) {
         v.visit_ty_params(tps, e, v);
         visit_enum_def(enum_definition, tps, e, v);
       }
-      item_impl(tps, traits, ty, methods_opt) => {
+      item_impl(tps, traits, ty, methods) => {
         v.visit_ty_params(tps, e, v);
         for traits.each |p| {
             visit_path(p.path, e, v);
         }
         v.visit_ty(ty, e, v);
-        for methods_opt.each |methods| {
-            for methods.each |m| {
-                visit_method_helper(*m, e, v)
-            }
+        for methods.each |m| {
+            visit_method_helper(*m, e, v)
         }
       }
       item_class(struct_def, tps) => {