Merge pull request #1265 from zhaoguoquan94/lambda_unused_error

Fix build failed issue for apple's clang 9.1 due to unused-lambda-capture error

Author: pervazea

src/gc/transaction_level_gc_manager.cpp

@@ -139,7 +139,7 @@ int TransactionLevelGCManager::Unlink(const int &thread_id,
         uint64_t timestamp = txn_ctx->GetTimestamp();
         auto &pool = threadpool::MonoQueuePool::GetBrainInstance();
         for(auto query_string: query_strings) {
-          pool.SubmitTask([this, query_string, timestamp] {
+          pool.SubmitTask([query_string, timestamp] {
             brain::QueryLogger::LogQuery(query_string, timestamp);
           });        
         }

src/include/index/bwtree.h

@@ -4587,7 +4587,7 @@ class BwTree : public BwTreeBase {
 
     // This is not used since in this case we do not need to compare
     // for equal relation
-    auto f2 = [this](const LeafDataNode *ldn1, const LeafDataNode *ldn2) {
+    auto f2 = [](const LeafDataNode *ldn1, const LeafDataNode *ldn2) {
       (void)ldn1;
       (void)ldn2;
 

src/traffic_cop/traffic_cop.cpp

@@ -191,7 +191,7 @@ executor::ExecutionResult TrafficCop::ExecuteHelper(
   };
 
   auto &pool = threadpool::MonoQueuePool::GetInstance();
-  pool.SubmitTask([plan, txn, &params, &result, &result_format, on_complete] {
+  pool.SubmitTask([plan, txn, &params, &result_format, on_complete] {
     executor::PlanExecutor::ExecutePlan(plan, txn, params, result_format,
                                         on_complete);
   });