diff --git a/quic/core/quic_circular_deque.h b/quic/core/quic_circular_deque.h
index 3a34626..39eed8e 100644
--- a/quic/core/quic_circular_deque.h
+++ b/quic/core/quic_circular_deque.h
@@ -157,17 +157,18 @@
     }
 
     void Decrement() {
-      DCHECK_GE(ExternalPosition(), 1);
+      DCHECK_GE(ExternalPosition(), 1u);
       index_ = deque_->index_prev(index_);
     }
 
     void IncrementBy(difference_type delta) {
       if (delta >= 0) {
         // After increment we are before or at end().
-        DCHECK_LE(ExternalPosition() + delta, deque_->size());
+        DCHECK_LE(static_cast<size_type>(ExternalPosition() + delta),
+                  deque_->size());
       } else {
         // After decrement we are after or at begin().
-        DCHECK_GE(ExternalPosition(), -delta);
+        DCHECK_GE(ExternalPosition(), static_cast<size_type>(-delta));
       }
       index_ = deque_->index_increment_by(index_, delta);
     }
@@ -714,7 +715,7 @@
       return index;
     }
 
-    DCHECK_LT(std::abs(delta), data_capacity());
+    DCHECK_LT(static_cast<size_type>(std::abs(delta)), data_capacity());
     return (index + data_capacity() + delta) % data_capacity();
   }
 
diff --git a/quic/test_tools/fuzzing/quic_framer_process_data_packet_fuzzer.cc b/quic/test_tools/fuzzing/quic_framer_process_data_packet_fuzzer.cc
index 44dc275..21d4ed6 100644
--- a/quic/test_tools/fuzzing/quic_framer_process_data_packet_fuzzer.cc
+++ b/quic/test_tools/fuzzing/quic_framer_process_data_packet_fuzzer.cc
@@ -3,9 +3,9 @@
 // found in the LICENSE file.
 
 #include <fuzzer/FuzzedDataProvider.h>
-#include <cstdint>
-
 #include <algorithm>
+#include <cstdint>
+#include <string>
 
 #include "net/third_party/quiche/src/quic/core/crypto/null_decrypter.h"
 #include "net/third_party/quiche/src/quic/core/crypto/null_encrypter.h"
@@ -87,7 +87,7 @@
 
   header.form = ConsumePacketHeaderFormat(provider, header.version);
 
-  const string cid_bytes =
+  const std::string cid_bytes =
       provider->ConsumeBytesAsString(kQuicDefaultConnectionIdLength);
   if (receiver_perspective == Perspective::IS_SERVER) {
     header.destination_connection_id =