diff --git a/src/librustc_data_structures/bitvec.rs b/src/librustc_data_structures/bitvec.rs
index 9004af35aef..04d6cb5e2a6 100644
--- a/src/librustc_data_structures/bitvec.rs
+++ b/src/librustc_data_structures/bitvec.rs
@@ -557,7 +557,7 @@ fn matrix_iter() {
 
 #[test]
 fn sparse_matrix_iter() {
-    let mut matrix: SparseBitMatrix<usize, usize> = SparseBitMatrix::new(64, 100);
+    let mut matrix: SparseBitMatrix<usize, usize> = SparseBitMatrix::new(100);
     matrix.add(3, 22);
     matrix.add(3, 75);
     matrix.add(2, 99);