diff --git a/src/shrpx.cc b/src/shrpx.cc
index b346aa99..b6f442d7 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -630,7 +630,8 @@ void renew_ticket_key_cb(struct ev_loop *loop, ev_timer *w, int revents) {
   new_key.hmac = EVP_sha256();
   new_key.hmac_keylen = EVP_MD_size(new_key.hmac);
 
-  assert(EVP_CIPHER_key_length(new_key.cipher) <= sizeof(new_key.data.enc_key));
+  assert(static_cast<size_t>(EVP_CIPHER_key_length(new_key.cipher)) <=
+         sizeof(new_key.data.enc_key));
   assert(new_key.hmac_keylen <= sizeof(new_key.data.hmac_key));
 
   if (LOG_ENABLED(INFO)) {
diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index b51d44e2..4db9c060 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -171,7 +171,7 @@ read_tls_ticket_key_file(const std::vector<std::string> &files,
       return nullptr;
     }
 
-    if (fst.st_size != expectedlen) {
+    if (static_cast<size_t>(fst.st_size) != expectedlen) {
       LOG(ERROR) << "tls-ticket-key-file: the expected file size is "
                  << expectedlen << ", the actual file size is " << fst.st_size;
       return nullptr;
@@ -184,7 +184,7 @@ read_tls_ticket_key_file(const std::vector<std::string> &files,
     }
 
     f.read(buf, expectedlen);
-    if (f.gcount() != expectedlen) {
+    if (static_cast<size_t>(f.gcount()) != expectedlen) {
       LOG(ERROR) << "tls-ticket-key-file: want to read " << expectedlen
                  << " bytes but only read " << f.gcount() << " bytes from "
                  << file;
@@ -1836,7 +1836,7 @@ int parse_config(const char *opt, const char *optarg,
       return -1;
     }
 
-    included_set.emplace(optarg);
+    included_set.insert(optarg);
     auto rv = load_config(optarg, included_set);
     included_set.erase(optarg);