From 95ae1105d9e5132fc79c3c21e800469dc4c762b1 Mon Sep 17 00:00:00 2001
From: Nikolai Kochetov <nik-kochetov@yandex-team.ru>
Date: Tue, 15 Sep 2020 02:05:43 +0300
Subject: [PATCH] Remove virtual destructors for Visitor.

---
 src/Common/Visitor.h                          | 19 ++++++++++++++++++-
 src/Functions/GatherUtils/ArraySinkVisitor.h  |  4 ++--
 .../GatherUtils/ArraySourceVisitor.h          |  4 ++--
 src/Functions/GatherUtils/Selectors.h         |  6 +++---
 .../GatherUtils/ValueSourceVisitor.h          |  4 ++--
 5 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/src/Common/Visitor.h b/src/Common/Visitor.h
index 7aef573a566..26ee66681e9 100644
--- a/src/Common/Visitor.h
+++ b/src/Common/Visitor.h
@@ -66,7 +66,8 @@ class Visitor<>
 public:
     using List = TypeList<>;
 
-    virtual ~Visitor() = default;
+protected:
+    ~Visitor() = default;
 };
 
 template <typename Type>
@@ -76,6 +77,9 @@ public:
     using List = TypeList<Type>;
 
     virtual void visit(Type &) = 0;
+
+protected:
+    ~Visitor() = default;
 };
 
 template <typename Type, typename ... Types>
@@ -86,6 +90,9 @@ public:
     using Visitor<Types ...>::visit;
 
     virtual void visit(Type &) = 0;
+
+protected:
+    ~Visitor() = default;
 };
 
 
@@ -95,6 +102,8 @@ class VisitorImplHelper;
 template <typename Derived, typename VisitorBase>
 class VisitorImplHelper<Derived, VisitorBase> : public VisitorBase
 {
+protected:
+    ~VisitorImplHelper() = default;
 };
 
 template <typename Derived, typename VisitorBase, typename Type>
@@ -111,6 +120,8 @@ protected:
         throw Exception("visitImpl(" + demangle(typeid(T).name()) + " &)" + " is not implemented for class"
                         + demangle(typeid(Derived).name()), ErrorCodes::LOGICAL_ERROR);
     }
+
+    ~VisitorImplHelper() = default;
 };
 
 template <typename Derived, typename VisitorBase, typename Type, typename ... Types>
@@ -128,6 +139,8 @@ protected:
         throw Exception("visitImpl(" + demangle(typeid(T).name()) + " &)" + " is not implemented for class"
                         + demangle(typeid(Derived).name()), ErrorCodes::LOGICAL_ERROR);
     }
+
+    ~VisitorImplHelper() = default;
 };
 
 template <typename Derived, typename VisitorBase>
@@ -140,6 +153,8 @@ class VisitorImpl : public
                 >::Type
         >::Type
 {
+protected:
+    ~VisitorImpl() = default;
 };
 
 template <typename Derived, typename Base, typename Visitor>
@@ -147,6 +162,8 @@ class Visitable : public Base
 {
 public:
     void accept(Visitor & visitor) override { visitor.visit(*static_cast<Derived *>(this)); }
+
+    //virtual ~Visitable() = default;
 };
 
 }
diff --git a/src/Functions/GatherUtils/ArraySinkVisitor.h b/src/Functions/GatherUtils/ArraySinkVisitor.h
index 1109b40f5da..addb231539a 100644
--- a/src/Functions/GatherUtils/ArraySinkVisitor.h
+++ b/src/Functions/GatherUtils/ArraySinkVisitor.h
@@ -19,10 +19,10 @@ using BasicArraySinks = typename AppendToTypeList<GenericArraySink, NumericArray
 using NullableArraySinks = typename TypeListMap<NullableArraySink, BasicArraySinks>::Type;
 using TypeListArraySinks = typename TypeListConcat<BasicArraySinks, NullableArraySinks>::Type;
 
-class ArraySinkVisitor : public ApplyTypeListForClass<Visitor, TypeListArraySinks>::Type {};
+using ArraySinkVisitor = typename ApplyTypeListForClass<Visitor, TypeListArraySinks>::Type;
 
 template <typename Derived>
-class ArraySinkVisitorImpl : public VisitorImpl<Derived, ArraySinkVisitor> {};
+using ArraySinkVisitorImpl = VisitorImpl<Derived, ArraySinkVisitor>;
 
 #pragma GCC visibility pop
 }
diff --git a/src/Functions/GatherUtils/ArraySourceVisitor.h b/src/Functions/GatherUtils/ArraySourceVisitor.h
index 98f7338ee12..59c8ea839a5 100644
--- a/src/Functions/GatherUtils/ArraySourceVisitor.h
+++ b/src/Functions/GatherUtils/ArraySourceVisitor.h
@@ -24,10 +24,10 @@ using BasicAndNullableArraySources = typename TypeListConcat<BasicArraySources,
 using ConstArraySources = typename TypeListMap<ConstSource, BasicAndNullableArraySources>::Type;
 using TypeListArraySources = typename TypeListConcat<BasicAndNullableArraySources, ConstArraySources>::Type;
 
-class ArraySourceVisitor : public ApplyTypeListForClass<Visitor, TypeListArraySources>::Type {};
+using ArraySourceVisitor = typename ApplyTypeListForClass<Visitor, TypeListArraySources>::Type;
 
 template <typename Derived>
-class ArraySourceVisitorImpl : public VisitorImpl<Derived, ArraySourceVisitor> {};
+using ArraySourceVisitorImpl = VisitorImpl<Derived, ArraySourceVisitor>;
 
 #pragma GCC visibility pop
 }
diff --git a/src/Functions/GatherUtils/Selectors.h b/src/Functions/GatherUtils/Selectors.h
index 4b32735b6a1..9c96b36460d 100644
--- a/src/Functions/GatherUtils/Selectors.h
+++ b/src/Functions/GatherUtils/Selectors.h
@@ -33,7 +33,7 @@ void callSelectMemberFunctionWithTupleArgument(Tuple & tuple, Args && ... args)
 }
 
 template <typename Base, typename ... Args>
-struct ArraySourceSelectorVisitor : public ArraySourceVisitorImpl<ArraySourceSelectorVisitor<Base, Args ...>>
+struct ArraySourceSelectorVisitor final : public ArraySourceVisitorImpl<ArraySourceSelectorVisitor<Base, Args ...>>
 {
     explicit ArraySourceSelectorVisitor(Args && ... args) : packed_args(args ...) {}
 
@@ -61,7 +61,7 @@ struct ArraySourceSelector
 
 
 template <typename Base, typename ... Args>
-struct ArraySinkSelectorVisitor : public ArraySinkVisitorImpl<ArraySinkSelectorVisitor<Base, Args ...>>
+struct ArraySinkSelectorVisitor final : public ArraySinkVisitorImpl<ArraySinkSelectorVisitor<Base, Args ...>>
 {
     explicit ArraySinkSelectorVisitor(Args && ... args) : packed_args(args ...) {}
 
@@ -89,7 +89,7 @@ struct ArraySinkSelector
 
 
 template <typename Base, typename ... Args>
-struct ValueSourceSelectorVisitor : public ValueSourceVisitorImpl<ValueSourceSelectorVisitor<Base, Args ...>>
+struct ValueSourceSelectorVisitor final : public ValueSourceVisitorImpl<ValueSourceSelectorVisitor<Base, Args ...>>
 {
     explicit ValueSourceSelectorVisitor(Args && ... args) : packed_args(args ...) {}
 
diff --git a/src/Functions/GatherUtils/ValueSourceVisitor.h b/src/Functions/GatherUtils/ValueSourceVisitor.h
index 63f94ea29e3..74be08cb4dd 100644
--- a/src/Functions/GatherUtils/ValueSourceVisitor.h
+++ b/src/Functions/GatherUtils/ValueSourceVisitor.h
@@ -24,10 +24,10 @@ using BasicAndNullableValueSources = typename TypeListConcat<BasicValueSources,
 using ConstValueSources = typename TypeListMap<ConstSource, BasicAndNullableValueSources>::Type;
 using TypeListValueSources = typename TypeListConcat<BasicAndNullableValueSources, ConstValueSources>::Type;
 
-class ValueSourceVisitor : public ApplyTypeListForClass<Visitor, TypeListValueSources>::Type {};
+using ValueSourceVisitor = typename ApplyTypeListForClass<Visitor, TypeListValueSources>::Type;
 
 template <typename Derived>
-class ValueSourceVisitorImpl : public VisitorImpl<Derived, ValueSourceVisitor> {};
+using ValueSourceVisitorImpl = VisitorImpl<Derived, ValueSourceVisitor>;
 
 #pragma GCC visibility pop
 }