diff --git a/lib/ngtcp2_conv.c b/lib/ngtcp2_conv.c
index 18cf314791384dd97ae5be12c3e6588d59d3ad71..0f150fea2b77c5b3668473cb6cd3f29733c79a92 100644
--- a/lib/ngtcp2_conv.c
+++ b/lib/ngtcp2_conv.c
@@ -85,9 +85,11 @@ uint64_t ngtcp2_get_varint(size_t *plen, const uint8_t *p) {
     memcpy(&n, p, 8);
     n.b[0] &= 0x3f;
     return ngtcp2_ntohl64(n.n64);
+  default:
+    assert(0);
   }
 
-  assert(0);
+  return 0;
 }
 
 int64_t ngtcp2_get_pkt_num(const uint8_t *p, size_t pkt_numlen) {
diff --git a/lib/ngtcp2_pkt.c b/lib/ngtcp2_pkt.c
index 257f22e892de64c80cd450dd798d863aae3c46a4..3dafab2a1b90d45b0d80a302126184b40d263599 100644
--- a/lib/ngtcp2_pkt.c
+++ b/lib/ngtcp2_pkt.c
@@ -368,8 +368,8 @@ ngtcp2_ssize ngtcp2_pkt_encode_hd_long(uint8_t *out, size_t outlen,
 
   p = out;
 
-  *p++ = NGTCP2_HEADER_FORM_BIT | NGTCP2_FIXED_BIT_MASK |
-         (uint8_t)(hd->type << 4) | (uint8_t)(hd->pkt_numlen - 1);
+  *p++ = (uint8_t)(NGTCP2_HEADER_FORM_BIT | NGTCP2_FIXED_BIT_MASK |
+                   (hd->type << 4) | (uint8_t)(hd->pkt_numlen - 1));
   p = ngtcp2_put_uint32be(p, hd->version);
   *p++ = (uint8_t)hd->dcid.datalen;
   if (hd->dcid.datalen) {