remove compiler warnings from rust 1.19

src/gc/src/heap/gc/mod.rs

@@ -311,7 +311,7 @@ pub fn start_trace(
     lo_space: Arc<FreeListSpace>
 ) {
     // creates root deque
-    let (mut worker, stealer) = deque();
+    let (worker, stealer) = deque();
 
     while !work_stack.is_empty() {
         worker.push(work_stack.pop().unwrap());

tests/ir_macros.rs

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#![allow(unused_macros)]
+
 macro_rules! typedef {
     // int, floating point
     (($vm: expr) $name: ident = mu_int($len: expr)) => {

tests/test_ir/test_types.rs

@@ -24,12 +24,6 @@ macro_rules! assert_type (
     )
 );
 
-macro_rules! println_type (
-    ($test:expr) => (
-        println!("{}", $test)
-    )
-);
-
 /// create one of each MuType
 fn create_types() -> Vec<P<MuType>> {
     let mut types = vec![];