Add parser support for generalized where clauses

Implement support in the parser for generalized where clauses,
as well as the conversion of ast::WherePredicates to
ty::Predicate in `collect.rs`.

src/libsyntax/ast.rs

@@ -415,17 +415,26 @@ pub struct WhereClause {
 #[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
 pub enum WherePredicate {
     BoundPredicate(WhereBoundPredicate),
+    RegionPredicate(WhereRegionPredicate),
     EqPredicate(WhereEqPredicate)
 }
 
 #[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
 pub struct WhereBoundPredicate {
-    pub id: NodeId,
     pub span: Span,
-    pub ident: Ident,
+    pub bounded_ty: P<Ty>,
     pub bounds: OwnedSlice<TyParamBound>,
 }
 
+#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
+pub struct WhereRegionPredicate {
+    pub span: Span,
+    pub lifetime: Lifetime,
+    pub bound: Lifetime
+}
+
+impl Copy for WhereRegionPredicate {}
+
 #[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
 pub struct WhereEqPredicate {
     pub id: NodeId,