Change to fix build error in ioreg

Addition of where clause to Rust.

Author: bharrisau

ioreg/builder/register.rs

@@ -17,6 +17,7 @@ use std::gc::GC;
 use std::iter::FromIterator;
 use syntax::ast;
 use syntax::ast::P;
+use syntax::ast_util::empty_generics;
 use syntax::codemap::{respan, mk_sp};
 use syntax::ext::base::ExtCtxt;
 use syntax::ext::build::AstBuilder;
@@ -80,7 +81,7 @@ fn build_field_type<'a>(cx: &'a ExtCtxt, path: &Vec<String>,
       let item: P<ast::Item> = box(GC) ast::Item {
         ident: name,
         id: ast::DUMMY_NODE_ID,
-        node: ast::ItemEnum(enum_def, utils::no_generics()),
+        node: ast::ItemEnum(enum_def, empty_generics()),
         vis: ast::Public,
         attrs: attrs,
         span: field.ty.span,

ioreg/builder/union.rs

@@ -17,6 +17,7 @@ use std::gc::{Gc, GC};
 use std::iter::FromIterator;
 use syntax::ast;
 use syntax::ast::P;
+use syntax::ast_util::empty_generics;
 use syntax::codemap::{DUMMY_SP, dummy_spanned};
 use syntax::ext::base::ExtCtxt;
 use syntax::ext::build::AstBuilder;
@@ -193,7 +194,7 @@ impl<'a, 'b, 'c> BuildUnionTypes<'a, 'b, 'c> {
       ident: self.cx.ident_of(name.node.as_slice()),
       attrs: attrs,
       id: ast::DUMMY_NODE_ID,
-      node: ast::ItemStruct(box(GC) struct_def, utils::no_generics()),
+      node: ast::ItemStruct(box(GC) struct_def, empty_generics()),
       vis: ast::Public,
       span: name.span,
     }

ioreg/builder/utils.rs

@@ -18,18 +18,10 @@ use syntax::ast;
 use syntax::ast::P;
 use syntax::codemap::DUMMY_SP;
 use syntax::ext::build::AstBuilder;
-use syntax::owned_slice::OwnedSlice;
 use syntax::parse::token;
 
 use super::super::node;
 
-pub fn no_generics() -> ast::Generics {
-  ast::Generics {
-    lifetimes: Vec::new(),
-    ty_params: OwnedSlice::empty()
-  }
-}
-
 /// Generate an unsuffixed integer literal expression with a dummy span
 pub fn expr_int<'a>(cx: &'a ExtCtxt, n: i64) -> P<ast::Expr> {
   let sign = if n < 0 {ast::Minus} else {ast::Plus};