diff --git a/vlib/crypto/md5/md5.v b/vlib/crypto/md5/md5.v
index fe0a19e211f2b0..fff3f0d514c31f 100644
--- a/vlib/crypto/md5/md5.v
+++ b/vlib/crypto/md5/md5.v
@@ -66,7 +66,7 @@ pub fn new() &Digest {
 }
 
 // write writes the contents of `p_` to the internal hash representation.
-pub fn (mut d Digest) write(p_ []u8) ?int {
+pub fn (mut d Digest) write(p_ []u8) !int {
 	unsafe {
 		mut p := p_
 		nn := p.len