diff --git a/src/libsodium/crypto_onetimeauth/poly1305/donna/auth_poly1305_donna.c b/src/libsodium/crypto_onetimeauth/poly1305/donna/auth_poly1305_donna.c
index 4c70a813..61b8d3d4 100644
--- a/src/libsodium/crypto_onetimeauth/poly1305/donna/auth_poly1305_donna.c
+++ b/src/libsodium/crypto_onetimeauth/poly1305/donna/auth_poly1305_donna.c
@@ -64,6 +64,10 @@ static int
 crypto_onetimeauth_poly1305_donna_init(crypto_onetimeauth_poly1305_state *state,
                                        const unsigned char *key)
 {
+    (void) sizeof(int[sizeof (crypto_onetimeauth_poly1305_state) >=
+                      sizeof (poly1305_context) ? 1 : -1]);
+    (void) sizeof(int[sizeof (poly1305_context) >=
+                      sizeof (poly1305_state_internal_t) ? 1 : -1]);
     poly1305_init((poly1305_context *) state, key);
 
     return 0;