Fix warnings under clang-15 (#315)

Signed-off-by: JaySon-Huang <[email protected]>

cache/lru_cache.cc

@@ -91,7 +91,7 @@ void LRUHandleTable::Resize() {
   std::unique_ptr<LRUHandle* []> new_list {
     new LRUHandle* [size_t{1} << new_length_bits] {}
   };
-  uint32_t count = 0;
+  [[maybe_unused]] uint32_t count = 0;
   for (uint32_t i = 0; i < old_length; i++) {
     LRUHandle* h = list_[i];
     while (h != nullptr) {

db/version_edit_handler.cc

@@ -26,7 +26,7 @@ void VersionEditHandlerBase::Iterate(log::Reader& reader,
   assert(log_read_status);
   assert(log_read_status->ok());
 
-  size_t recovered_edits = 0;
+  [[maybe_unused]] size_t recovered_edits = 0;
   Status s = Initialize();
   while (reader.LastRecordEnd() < max_manifest_read_size_ && s.ok() &&
          reader.ReadRecord(&record, &scratch) && log_read_status->ok()) {

db/version_set.cc

@@ -3108,13 +3108,9 @@ void VersionStorageInfo::SetFinalized() {
     assert(MaxBytesForLevel(level) >= max_bytes_prev_level);
     max_bytes_prev_level = MaxBytesForLevel(level);
   }
-  int num_empty_non_l0_level = 0;
   for (int level = 0; level < num_levels(); level++) {
     assert(LevelFiles(level).size() == 0 ||
            LevelFiles(level).size() == LevelFilesBrief(level).num_files);
-    if (level > 0 && NumLevelBytes(level) > 0) {
-      num_empty_non_l0_level++;
-    }
     if (LevelFiles(level).size() > 0) {
       assert(level < num_non_empty_levels());
     }

third-party/folly/folly/Traits.h

@@ -13,7 +13,7 @@ namespace folly {
 #if !defined(_MSC_VER)
 template <class T>
 struct is_trivially_copyable
-    : std::integral_constant<bool, __has_trivial_copy(T)> {};
+    : std::integral_constant<bool, __is_trivially_copyable(T)> {};
 #else
 template <class T>
 using is_trivially_copyable = std::is_trivially_copyable<T>;