diff --git a/quic/core/quic_connection_test.cc b/quic/core/quic_connection_test.cc
index f416ae6..e5ab141 100644
--- a/quic/core/quic_connection_test.cc
+++ b/quic/core/quic_connection_test.cc
@@ -11356,7 +11356,7 @@
     connection_.SetEncrypter(ENCRYPTION_FORWARD_SECURE,
                              std::make_unique<TaggingEncrypter>(0x02));
     connection_.SetDefaultEncryptionLevel(ENCRYPTION_FORWARD_SECURE);
-    SendStreamDataToPeer(2, string(1286, 'a'), 0, NO_FIN, nullptr);
+    SendStreamDataToPeer(2, std::string(1286, 'a'), 0, NO_FIN, nullptr);
     connection_.SetDefaultEncryptionLevel(ENCRYPTION_HANDSHAKE);
     // Try to coalesce a HANDSHAKE packet after 1-RTT packet.
     if (GetQuicReloadableFlag(quic_fix_min_crypto_frame_size)) {
diff --git a/quic/core/quic_tag.cc b/quic/core/quic_tag.cc
index b25c5b7..e15787b 100644
--- a/quic/core/quic_tag.cc
+++ b/quic/core/quic_tag.cc
@@ -83,7 +83,7 @@
   }
   QuicTag tag = 0;
   // Iterate over every character from right to left.
-  for (auto it = tag_string.crbegin(); it != tag_string.crend(); ++it) {
+  for (auto it = tag_string.rbegin(); it != tag_string.rend(); ++it) {
     // The cast here is required on platforms where char is signed.
     unsigned char token_char = static_cast<unsigned char>(*it);
     tag <<= 8;
diff --git a/quic/core/quic_tag_test.cc b/quic/core/quic_tag_test.cc
index 3dc93ad..fa031ac 100644
--- a/quic/core/quic_tag_test.cc
+++ b/quic/core/quic_tag_test.cc
@@ -42,7 +42,7 @@
   EXPECT_EQ(ParseQuicTag("IJK"), tag_ijk);
   QuicTag tag_l = MakeQuicTag('L', 0, 0, 0);
   EXPECT_EQ(ParseQuicTag("L"), tag_l);
-  QuicTag tag_hex = MakeQuicTag('M', 'N', 'O', 255);
+  QuicTag tag_hex = MakeQuicTag('M', 'N', 'O', static_cast<char>(255));
   EXPECT_EQ(ParseQuicTag("4d4e4fff"), tag_hex);
   EXPECT_EQ(ParseQuicTag("4D4E4FFF"), tag_hex);
   QuicTag tag_zero = 0;