Add two new OperationKinds for increment and decrement operators

Fixes https://github.com/dotnet/roslyn/issues/21748

Add two new OperationKinds for increment and decrement operators
Fixes https://github.com/dotnet/roslyn/issues/21748
7f999cfb · Manish Vasani · 04518743 · 7f999cfb · 7f999cfb · 7f999cfb
14 changed file
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs
@@ -591,7 +591,7 @@ void F(int[] a)
      Operand: IParameterReferenceExpression: a (OperationKind.ParameterReferenceExpression, Type: System.Int32[]) (Syntax: 'a')
  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '{ x++; }')
      IExpressionStatement (OperationKind.ExpressionStatement, IsInvalid) (Syntax: 'x++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Object, IsInvalid) (Syntax: 'x++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Object, IsInvalid) (Syntax: 'x++')
            Target: IInvalidExpression (OperationKind.InvalidExpression, Type: System.Int32, IsInvalid) (Syntax: 'x')
                Children(1):
                    ILocalReferenceExpression: x (OperationKind.LocalReferenceExpression, Type: System.Int32, IsInvalid) (Syntax: 'x')

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
@@ -1631,7 +1631,7 @@ static void Main(string[] args)
                            Right: IParameterReferenceExpression: x (OperationKind.ParameterReferenceExpression, Type: System.Int32) (Syntax: 'x')
  AtLoopBottom:
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
  Body: IBlockStatement (2 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      Locals: Local_1: System.Func<System.Int32, System.Int32> lambda
@@ -1772,7 +1772,7 @@ public class C1
              Initializer: null
  AtLoopBottom:
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++')
-        Expression: IIncrementExpression (PostfixIncrement) (OperatorMethod: C1 C1.op_Increment(C1 obj)) (OperationKind.IncrementExpression, Type: C1) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperatorMethod: C1 C1.op_Increment(C1 obj)) (OperationKind.IncrementExpression, Type: C1) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: C1) (Syntax: 'i')
  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ }')
 ";
@@ -1806,11 +1806,11 @@ static void Main(string[] args)
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'j = i++')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'j = i++')
          Variables: Local_1: System.Int32 j
-          Initializer: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+          Initializer: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
              Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
  AtLoopBottom:
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: '++j')
-        Expression: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++j')
+        Expression: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++j')
            Target: ILocalReferenceExpression: j (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'j')
  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'System.Cons ... iteLine(j);')
@@ -1853,11 +1853,11 @@ static void Main(string[] args)
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'j = ++i')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'j = ++i')
          Variables: Local_1: System.Int32 j
-          Initializer: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
+          Initializer: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
              Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
  AtLoopBottom:
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: '++j')
-        Expression: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++j')
+        Expression: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++j')
            Target: ILocalReferenceExpression: j (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'j')
  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'System.Cons ... iteLine(j);')
@@ -1892,7 +1892,7 @@ static void Main(string[] args)
 IForLoopStatement (LoopKind.For) (OperationKind.LoopStatement) (Syntax: 'for (int i  ... }')
  Locals: Local_1: System.Int32 i
  Condition: IBinaryOperatorExpression (BinaryOperatorKind.LessThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: '++i < 5')
-      Left: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
+      Left: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
          Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
      Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 5) (Syntax: '5')
  Before:
@@ -1943,7 +1943,7 @@ static int foo(int x)
          Instance Receiver: null
          Arguments(1):
              IArgument (ArgumentKind.Explicit, Matching Parameter: x) (OperationKind.Argument) (Syntax: 'i--')
-                IIncrementExpression (PostfixDecrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i--')
+                IIncrementExpression (Postfix) (OperationKind.DecrementExpression, Type: System.Int32) (Syntax: 'i--')
                  Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
                InConversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
                OutConversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
@@ -2089,7 +2089,7 @@ private void M()
              WhenFalse: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
  AtLoopBottom:
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'System.Cons ... }, s={s}"");')

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILocalFunctionStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILocalFunctionStatement.cs
@@ -30,7 +30,7 @@ public void M(int x)
 ILocalFunctionStatement (Symbol: System.Int32 Local(System.Int32 p1)) (OperationKind.LocalFunctionStatement) (Syntax: 'int Local(i ... }')
  IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
    IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'return x++;')
-      ReturnedValue: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
+      ReturnedValue: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
          Target: IParameterReferenceExpression: x (OperationKind.ParameterReferenceExpression, Type: System.Int32) (Syntax: 'x')
 ";
            var expectedDiagnostics = DiagnosticDescription.None;
@@ -56,7 +56,7 @@ public void M(int x)
 ILocalFunctionStatement (Symbol: System.Int32 Local(System.Int32 p1)) (OperationKind.LocalFunctionStatement) (Syntax: 'int Local(i ... p1) => x++;')
  IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '=> x++')
    IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'x++')
-      ReturnedValue: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
+      ReturnedValue: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
          Target: IParameterReferenceExpression: x (OperationKind.ParameterReferenceExpression, Type: System.Int32) (Syntax: 'x')
 ";
            var expectedDiagnostics = DiagnosticDescription.None;
@@ -82,7 +82,7 @@ public void M()
 ILocalFunctionStatement (Symbol: System.Int32 Local(System.Int32 x)) (OperationKind.LocalFunctionStatement) (Syntax: 'int Local(int x) => x++;')
  IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '=> x++')
    IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'x++')
-      ReturnedValue: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
+      ReturnedValue: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
          Target: IParameterReferenceExpression: x (OperationKind.ParameterReferenceExpression, Type: System.Int32) (Syntax: 'x')
 ";
            var expectedDiagnostics = DiagnosticDescription.None;
@@ -281,7 +281,7 @@ void M()
 ILocalFunctionStatement (Symbol: void F()) (OperationKind.LocalFunctionStatement) (Syntax: 'void F() => x++;')
  IBlockStatement (2 statements) (OperationKind.BlockStatement) (Syntax: '=> x++')
    IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'x++')
-      Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
+      Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'x++')
          Target: ILocalReferenceExpression: x (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'x')
    IReturnStatement (OperationKind.ReturnStatement) (Syntax: '=> x++')
      ReturnedValue: null

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IUnaryOperatorExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IUnaryOperatorExpression.cs
@@ -3038,7 +3038,7 @@ int Method()
 }
 ";
            string expectedOperationTree = @"
-IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
+IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
  Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
 ";

@@ -3060,7 +3060,7 @@ int Method()
 }
 ";
            string expectedOperationTree = @"
-IIncrementExpression (PrefixDecrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '--i')
+IIncrementExpression (Prefix) (OperationKind.DecrementExpression, Type: System.Int32) (Syntax: '--i')
  Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
 ";
            VerifyOperationTreeForTest<PrefixUnaryExpressionSyntax>(source, expectedOperationTree);

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs
@@ -47,7 +47,7 @@ static void Main()
                Indices(1):
                    ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
 ";
            VerifyOperationTreeForTest<DoStatementSyntax>(source, expectedOperationTree);
@@ -87,7 +87,7 @@ static int SumWhile()
            Left: ILocalReferenceExpression: sum (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'sum')
            Right: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
 ";
            VerifyOperationTreeForTest<WhileStatementSyntax>(source, expectedOperationTree);
@@ -125,7 +125,7 @@ static void Main()
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'int value = ++index;')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'int value = ++index;')
          Variables: Local_1: System.Int32 value
-          Initializer: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
+          Initializer: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
              Target: ILocalReferenceExpression: index (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'index')
      IIfStatement (OperationKind.IfStatement) (Syntax: 'if (value > ... }')
        Condition: IBinaryOperatorExpression (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'value > 10')
@@ -174,7 +174,7 @@ static void Main()
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'int value = ++index;')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'int value = ++index;')
          Variables: Local_1: System.Int32 value
-          Initializer: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
+          Initializer: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
              Target: ILocalReferenceExpression: index (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'index')
      IIfStatement (OperationKind.IfStatement) (Syntax: 'if (value > ... }')
        Condition: IBinaryOperatorExpression (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'value > 5')
@@ -235,7 +235,7 @@ static void Main()
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'int value = ++index;')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'int value = ++index;')
          Variables: Local_1: System.Int32 value
-          Initializer: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
+          Initializer: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
              Target: ILocalReferenceExpression: index (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'index')
      IIfStatement (OperationKind.IfStatement) (Syntax: 'if (value > ... }')
        Condition: IBinaryOperatorExpression (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'value > 100')
@@ -314,7 +314,7 @@ static void Main()
                  InConversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
                  OutConversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'value--;')
-        Expression: IIncrementExpression (PostfixDecrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'value--')
+        Expression: IIncrementExpression (Postfix) (OperationKind.DecrementExpression, Type: System.Int32) (Syntax: 'value--')
            Target: ILocalReferenceExpression: value (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'value')
 ";
            VerifyOperationTreeForTest<WhileStatementSyntax>(source, expectedOperationTree);
@@ -387,7 +387,7 @@ public static int GetFirstEvenNumber(int number)
              ReturnedValue: IParameterReferenceExpression: number (OperationKind.ParameterReferenceExpression, Type: System.Int32) (Syntax: 'number')
        IfFalse: null
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'number++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'number++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'number++')
            Target: IParameterReferenceExpression: number (OperationKind.ParameterReferenceExpression, Type: System.Int32) (Syntax: 'number')
 ";
            VerifyOperationTreeForTest<WhileStatementSyntax>(source, expectedOperationTree);
@@ -433,7 +433,7 @@ public static int GetFirstEvenNumber(int number)
            IBranchStatement (BranchKind.GoTo, Label: Even) (OperationKind.BranchStatement) (Syntax: 'goto Even;')
        IfFalse: null
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'number++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'number++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'number++')
            Target: IParameterReferenceExpression: number (OperationKind.ParameterReferenceExpression, Type: System.Int32) (Syntax: 'number')
      ILabeledStatement (Label: Even) (OperationKind.LabeledStatement) (Syntax: 'Even: ... urn number;')
        Statement: IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'return number;')
@@ -473,7 +473,7 @@ static void Main()
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'int value = ++index;')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'int value = ++index;')
          Variables: Local_1: System.Int32 value
-          Initializer: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
+          Initializer: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++index')
              Target: ILocalReferenceExpression: index (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'index')
      IIfStatement (OperationKind.IfStatement) (Syntax: 'if (value > ... }')
        Condition: IBinaryOperatorExpression (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'value > 100')
@@ -545,7 +545,7 @@ static void Main()
      Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 10) (Syntax: '10')
  Body: IBlockStatement (3 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
      IIfStatement (OperationKind.IfStatement) (Syntax: 'if (i < 9) ... }')
        Condition: IBinaryOperatorExpression (BinaryOperatorKind.LessThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'i < 9')
@@ -598,7 +598,7 @@ static void Main()
  Body: IBlockStatement (4 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 j
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'int j = 0;')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'int j = 0;')
@@ -610,7 +610,7 @@ static void Main()
            Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 10) (Syntax: '10')
        Body: IBlockStatement (2 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'j++;')
-              Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'j++')
+              Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'j++')
                  Target: ILocalReferenceExpression: j (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'j')
            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'System.Cons ... iteLine(j);')
              Expression: IInvocationExpression (void System.Console.WriteLine(System.Int32 value)) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'System.Cons ... riteLine(j)')
@@ -665,7 +665,7 @@ static void Main()
  Body: IBlockStatement (4 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 j
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
      IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'int j = 0;')
        IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'int j = 0;')
@@ -677,7 +677,7 @@ static void Main()
            Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 10) (Syntax: '10')
        Body: IBlockStatement (3 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'j++;')
-              Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'j++')
+              Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'j++')
                  Target: ILocalReferenceExpression: j (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'j')
            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i = i + j;')
              Expression: ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Int32) (Syntax: 'i = i + j')
@@ -788,7 +788,7 @@ static void Main(string[] args)
            string expectedOperationTree = @"
 IWhileLoopStatement (LoopKind.While) (OperationKind.LoopStatement) (Syntax: 'while ( ++i ... }')
  Condition: IBinaryOperatorExpression (BinaryOperatorKind.LessThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: '++i < 5')
-      Left: IIncrementExpression (PrefixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
+      Left: IIncrementExpression (Prefix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: '++i')
          Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
      Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 5) (Syntax: '5')
  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
@@ -827,7 +827,7 @@ static void Main(string[] args)
      Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'i++;')
-        Expression: IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
+        Expression: IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'i++')
            Target: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
 ";
            VerifyOperationTreeForTest<WhileStatementSyntax>(source, expectedOperationTree);
@@ -892,7 +892,7 @@ public void TryMethod()
  Condition: IBinaryOperatorExpression (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'x-- > 0')
      Left: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Int32) (Syntax: 'x--')
          Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: True, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-          Operand: IIncrementExpression (PostfixDecrement) (OperationKind.IncrementExpression, Type: System.SByte) (Syntax: 'x--')
+          Operand: IIncrementExpression (Postfix) (OperationKind.DecrementExpression, Type: System.SByte) (Syntax: 'x--')
              Target: ILocalReferenceExpression: x (OperationKind.LocalReferenceExpression, Type: System.SByte) (Syntax: 'x')
      Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')

--- a/src/Compilers/CSharp/Test/Semantic/Semantics/ObjectAndCollectionInitializerTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/ObjectAndCollectionInitializerTests.cs
@@ -1381,7 +1381,7 @@ public static void Main()
            Left: IFieldReferenceExpression: System.Int32 MemberInitializerTest.x (OperationKind.FieldReferenceExpression, Type: System.Int32) (Syntax: 'x')
                Instance Receiver: IInstanceReferenceExpression (OperationKind.InstanceReferenceExpression, Type: MemberInitializerTest) (Syntax: 'x')
            Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
-          IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Object, IsInvalid) (Syntax: 'y++')
+          IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Object, IsInvalid) (Syntax: 'y++')
            Target: IFieldReferenceExpression: System.Int32 MemberInitializerTest.y (OperationKind.FieldReferenceExpression, Type: System.Int32, IsInvalid) (Syntax: 'y')
                Instance Receiver: IInstanceReferenceExpression (OperationKind.InstanceReferenceExpression, Type: MemberInitializerTest, IsInvalid) (Syntax: 'y')
 ";
@@ -1993,7 +1993,7 @@ public static void Main()
      Initializers(1):
          IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: 'y++')
            Children(1):
-                IIncrementExpression (PostfixIncrement) (OperationKind.IncrementExpression, Type: System.Object, IsInvalid) (Syntax: 'y++')
+                IIncrementExpression (Postfix) (OperationKind.IncrementExpression, Type: System.Object, IsInvalid) (Syntax: 'y++')
                  Target: IFieldReferenceExpression: System.Int32 MemberInitializerTest.y (OperationKind.FieldReferenceExpression, Type: System.Int32, IsInvalid) (Syntax: 'y')
                      Instance Receiver: IInstanceReferenceExpression (OperationKind.InstanceReferenceExpression, Type: MemberInitializerTest, IsInvalid) (Syntax: 'y')
 ";

--- a/src/Compilers/CSharp/Test/Semantic/Semantics/OperatorTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/OperatorTests.cs
--- a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
+++ b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
@@ -2105,9 +2105,8 @@ public LazyIfStatement(Lazy<IOperation> condition, Lazy<IOperation> ifTrueStatem
    internal abstract partial class BaseIncrementExpression : Operation, IIncrementExpression
    {
        public BaseIncrementExpression(bool isDecrement, bool isPostfix, bool isLifted, bool isChecked, bool usesOperatorMethod, IMethodSymbol operatorMethod, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue, bool isImplicit) :
-            base(OperationKind.IncrementExpression, semanticModel, syntax, type, constantValue, isImplicit)
+            base(isDecrement ? OperationKind.DecrementExpression : OperationKind.IncrementExpression, semanticModel, syntax, type, constantValue, isImplicit)
        {
-            IsDecrement = isDecrement;
            IsPostfix = isPostfix;
            IsLifted = isLifted;
            IsChecked = isChecked;
@@ -2115,11 +2114,6 @@ internal abstract partial class BaseIncrementExpression : Operation, IIncrementE
            OperatorMethod = operatorMethod;
        }
        /// <summary>
-        /// <code>true</code> if this is a decrement expression.
-        /// <code>false</code> if this is an increment expression.
-        /// </summary>
-        public bool IsDecrement { get; }
-        /// <summary>
        /// <code>true</code> if this is a postfix expression.
        /// <code>false</code> if this is a prefix expression.
        /// </summary>

--- a/src/Compilers/Core/Portable/Operations/IIncrementExpression.cs
+++ b/src/Compilers/Core/Portable/Operations/IIncrementExpression.cs
@@ -3,7 +3,7 @@
 namespace Microsoft.CodeAnalysis.Semantics
 {
    /// <summary>
-    /// Represents an increment or decrement expression in C#.
+    /// Represents an increment (<see cref="OperationKind.IncrementExpression"/>) or decrement (<see cref="OperationKind.DecrementExpression"/>) expression in C#.
    /// </summary>
    /// <remarks>
    /// This interface is reserved for implementation by its associated APIs. We reserve the right to
@@ -16,12 +16,6 @@ public interface IIncrementExpression : IOperation, IHasOperatorMethodExpression
        /// </summary>
        IOperation Target { get; }

-        /// <summary>
-        /// <code>true</code> if this is a decrement expression.
-        /// <code>false</code> if this is an increment expression.
-        /// </summary>
-        bool IsDecrement { get; }
-
        /// <summary>
        /// <code>true</code> if this is a postfix expression.
        /// <code>false</code> if this is a prefix expression.

--- a/src/Compilers/Core/Portable/Operations/OperationCloner.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
@@ -382,7 +382,8 @@ public override IOperation VisitCompoundAssignmentExpression(ICompoundAssignment

        public override IOperation VisitIncrementExpression(IIncrementExpression operation, object argument)
        {
-            return new IncrementExpression(operation.IsDecrement, operation.IsPostfix, operation.IsLifted, operation.IsChecked, Visit(operation.Target), operation.UsesOperatorMethod, operation.OperatorMethod, ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue, operation.IsImplicit);
+            bool isDecrement = operation.Kind == OperationKind.DecrementExpression;
+            return new IncrementExpression(isDecrement, operation.IsPostfix, operation.IsLifted, operation.IsChecked, Visit(operation.Target), operation.UsesOperatorMethod, operation.OperatorMethod, ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue, operation.IsImplicit);
        }

        public override IOperation VisitParenthesizedExpression(IParenthesizedExpression operation, object argument)

--- a/src/Compilers/Core/Portable/Operations/OperationKind.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationKind.cs
@@ -162,10 +162,12 @@ public enum OperationKind
        //PointerIndirectionReferenceExpression = 0x204,
        /// <summary>Indicates an <see cref="IIsPatternExpression"/>.</summary>
        IsPatternExpression = 0x205,
-        /// <summary>Indicates an <see cref="IIncrementExpression"/>.</summary>
+        /// <summary>Indicates an <see cref="IIncrementExpression"/> for increment operator.</summary>
        IncrementExpression = 0x206,
        /// <summary>Indicates an <see cref="IThrowExpression"/>.</summary>
        ThrowExpression = 0x207,
+        /// <summary>Indicates an <see cref="IIncrementExpression"/> for decrement operator.</summary>
+        DecrementExpression = 0x208,

        // Expressions that occur only in Visual Basic.


--- a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
+++ b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
@@ -69,6 +69,7 @@ Microsoft.CodeAnalysis.OperationKind.ConditionalExpression = 271 -> Microsoft.Co
 Microsoft.CodeAnalysis.OperationKind.ConstantPattern = 1039 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.ConversionExpression = 258 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.DeclarationPattern = 1040 -> Microsoft.CodeAnalysis.OperationKind
+Microsoft.CodeAnalysis.OperationKind.DecrementExpression = 520 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.DefaultCaseClause = 1042 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.DefaultValueExpression = 512 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.DynamicInvocationExpression = 295 -> Microsoft.CodeAnalysis.OperationKind
@@ -329,7 +330,6 @@ Microsoft.CodeAnalysis.Semantics.IIfStatement.IfFalseStatement.get -> Microsoft.
 Microsoft.CodeAnalysis.Semantics.IIfStatement.IfTrueStatement.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.IIncrementExpression
 Microsoft.CodeAnalysis.Semantics.IIncrementExpression.IsChecked.get -> bool
-Microsoft.CodeAnalysis.Semantics.IIncrementExpression.IsDecrement.get -> bool
 Microsoft.CodeAnalysis.Semantics.IIncrementExpression.IsLifted.get -> bool
 Microsoft.CodeAnalysis.Semantics.IIncrementExpression.IsPostfix.get -> bool
 Microsoft.CodeAnalysis.Semantics.IIncrementExpression.Target.get -> Microsoft.CodeAnalysis.IOperation

--- a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
+++ b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
@@ -1230,7 +1230,6 @@ public override void VisitIncrementExpression(IIncrementExpression operation)
            LogString(nameof(IIncrementExpression));

            var kindStr = operation.IsPostfix ? "Postfix" : "Prefix";
-            kindStr += operation.IsDecrement ? "Decrement" : "Increment";
            if (operation.IsLifted)
            {
                kindStr += ", IsLifted";

--- a/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
+++ b/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
@@ -556,7 +556,6 @@ public override void VisitIncrementExpression(IIncrementExpression operation)
        {
            var usesOperatorMethod = operation.UsesOperatorMethod;
            var operatorMethod = operation.OperatorMethod;
-            var isDecrement = operation.IsDecrement;
            var isPostFix = operation.IsPostfix;

            base.VisitIncrementExpression(operation);