Fix inconsistent formatting of operator function and nulls action

src/Parsers/ASTFunction.cpp

@@ -813,8 +813,7 @@ void ASTFunction::formatImplWithoutAlias(const FormatSettings & settings, Format
 
     /// Should this function to be written as operator?
     bool written = false;
-
-    if (arguments && !parameters)
+    if (arguments && !parameters && nulls_action == NullsAction::EMPTY)
     {
         /// Unary prefix operators.
         if (arguments->children.size() == 1)

src/Storages/MergeTree/registerStorageMergeTree.cpp

@@ -1,6 +1,5 @@
 #include <Databases/DatabaseReplicatedHelpers.h>
 #include <Storages/MergeTree/MergeTreeIndexMinMax.h>
-#include <Storages/MergeTree/MergeTreeIndexSet.h>
 #include <Storages/MergeTree/MergeTreeIndices.h>
 #include <Storages/StorageFactory.h>
 #include <Storages/StorageMergeTree.h>
@@ -9,16 +8,12 @@
 #include <Common/Macros.h>
 #include <Common/OptimizedRegularExpression.h>
 #include <Common/typeid_cast.h>
-#include <Common/thread_local_rng.h>
 
-#include <Parsers/ASTCreateQuery.h>
-#include <Parsers/ASTExpressionList.h>
 #include <Parsers/ASTFunction.h>
 #include <Parsers/ASTIdentifier.h>
 #include <Parsers/ASTSetQuery.h>
 
 #include <AggregateFunctions/AggregateFunctionFactory.h>
-#include <AggregateFunctions/parseAggregateFunctionParameters.h>
 
 #include <Interpreters/Context.h>
 #include <Interpreters/FunctionNameNormalizer.h>

tests/queries/0_stateless/02998_operator_respect_nulls.sql

@@ -0,0 +1 @@
+SELECT plus(1, 1) RESPECT NULLS; -- { serverError SYNTAX_ERROR }