diff --git a/src/crypto/md5/md5.go b/src/crypto/md5/md5.go
index 7aeee603f7..fb2cbf4011 100644
--- a/src/crypto/md5/md5.go
+++ b/src/crypto/md5/md5.go
@@ -160,10 +160,10 @@ func (d *digest) Write(p []byte) (nn int, err error) {
 	return
 }
 
-func (d0 *digest) Sum(in []byte) []byte {
-	// Make a copy of d0 so that caller can keep writing and summing.
-	d := *d0
-	hash := d.checkSum()
+func (d *digest) Sum(in []byte) []byte {
+	// Make a copy of d so that caller can keep writing and summing.
+	d0 := *d
+	hash := d0.checkSum()
 	return append(in, hash[:]...)
 }