Refactors INullCoalescingExpression to ICoalesce expression, and prop…

…erties to sensible names.

src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs

@@ -869,14 +869,14 @@ private IConditionalChoiceExpression CreateBoundConditionalOperatorOperation(Bou
             return new LazyConditionalChoiceExpression(condition, ifTrueValue, ifFalseValue, _semanticModel, syntax, type, constantValue);
         }
 
-        private INullCoalescingExpression CreateBoundNullCoalescingOperatorOperation(BoundNullCoalescingOperator boundNullCoalescingOperator)
+        private ICoalesceExpression CreateBoundNullCoalescingOperatorOperation(BoundNullCoalescingOperator boundNullCoalescingOperator)
         {
-            Lazy<IOperation> primaryOperand = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.LeftOperand));
-            Lazy<IOperation> secondaryOperand = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.RightOperand));
+            Lazy<IOperation> expression = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.LeftOperand));
+            Lazy<IOperation> whenNull = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.RightOperand));
             SyntaxNode syntax = boundNullCoalescingOperator.Syntax;
             ITypeSymbol type = boundNullCoalescingOperator.Type;
             Optional<object> constantValue = ConvertToOptional(boundNullCoalescingOperator.ConstantValue);
-            return new LazyNullCoalescingExpression(primaryOperand, secondaryOperand, _semanticModel, syntax, type, constantValue);
+            return new LazyCoalesceExpression(expression, whenNull, _semanticModel, syntax, type, constantValue);
         }
 
         private IAwaitExpression CreateBoundAwaitExpressionOperation(BoundAwaitExpression boundAwaitExpression)

src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs

@@ -318,11 +318,11 @@ static void Main(string[] args)
 IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'object /*<b ... *</bind>*/;')
   IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'object /*<b ... *</bind>*/;')
     Variables: Local_1: System.Object o
-    Initializer: INullCoalescingExpression (OperationKind.NullCoalescingExpression, Type: System.Object) (Syntax: 'new object( ... Exception()')
-        Left: IObjectCreationExpression (Constructor: System.Object..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Object) (Syntax: 'new object()')
+    Initializer: ICoalesceExpression (OperationKind.CoalesceExpression, Type: System.Object) (Syntax: 'new object( ... Exception()')
+        Expression: IObjectCreationExpression (Constructor: System.Object..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Object) (Syntax: 'new object()')
             Arguments(0)
             Initializer: null
-        Right: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object) (Syntax: 'throw new Exception()')
+        WhenNull: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object) (Syntax: 'throw new Exception()')
             Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
             Operand: IThrowExpression (OperationKind.ThrowExpression, Type: null) (Syntax: 'throw new Exception()')
                 IObjectCreationExpression (Constructor: System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new Exception()')
@@ -342,7 +342,7 @@ static void Main(string[] args)
                     OperationSelector = (operation) =>
                     {
                         var initializer = ((IVariableDeclarationStatement)operation).Declarations.Single().Initializer;
-                        return (IConversionExpression)((INullCoalescingExpression)initializer).SecondaryOperand;
+                        return (IConversionExpression)((ICoalesceExpression)initializer).WhenNull;
                     }
                 }.Verify);
         }

src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs

@@ -3039,74 +3039,74 @@ public LazyMethodBindingExpression(IMethodSymbol method, bool isVirtual, Lazy<IO
     /// <summary>
     /// Represents a null-coalescing expression.
     /// </summary>
-    internal abstract partial class BaseNullCoalescingExpression : Operation, INullCoalescingExpression
+    internal abstract partial class BaseCoalesceExpression : Operation, ICoalesceExpression
     {
-        protected BaseNullCoalescingExpression(SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
-                    base(OperationKind.NullCoalescingExpression, semanticModel, syntax, type, constantValue)
+        protected BaseCoalesceExpression(SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+                    base(OperationKind.CoalesceExpression, semanticModel, syntax, type, constantValue)
         {
         }
 
-        protected abstract IOperation PrimaryOperandImpl { get; }
-        protected abstract IOperation SecondaryOperandImpl { get; }
+        protected abstract IOperation ExpressionImpl { get; }
+        protected abstract IOperation WhenNullImpl { get; }
         public override IEnumerable<IOperation> Children
         {
             get
             {
-                yield return PrimaryOperand;
-                yield return SecondaryOperand;
+                yield return Expression;
+                yield return WhenNull;
             }
         }
         /// <summary>
         /// Value to be unconditionally evaluated.
         /// </summary>
-        public IOperation PrimaryOperand => Operation.SetParentOperation(PrimaryOperandImpl, this);
+        public IOperation Expression => Operation.SetParentOperation(ExpressionImpl, this);
         /// <summary>
-        /// Value to be evaluated if Primary evaluates to null/Nothing.
+        /// Value to be evaluated if <see cref="Expression"/> evaluates to null/Nothing.
         /// </summary>
-        public IOperation SecondaryOperand => Operation.SetParentOperation(SecondaryOperandImpl, this);
+        public IOperation WhenNull => Operation.SetParentOperation(WhenNullImpl, this);
         public override void Accept(OperationVisitor visitor)
         {
-            visitor.VisitNullCoalescingExpression(this);
+            visitor.VisitCoalesceExpression(this);
         }
         public override TResult Accept<TArgument, TResult>(OperationVisitor<TArgument, TResult> visitor, TArgument argument)
         {
-            return visitor.VisitNullCoalescingExpression(this, argument);
+            return visitor.VisitCoalesceExpression(this, argument);
         }
     }
 
     /// <summary>
     /// Represents a null-coalescing expression.
     /// </summary>
-    internal sealed partial class NullCoalescingExpression : BaseNullCoalescingExpression, INullCoalescingExpression
+    internal sealed partial class CoalesceExpression : BaseCoalesceExpression, ICoalesceExpression
     {
-        public NullCoalescingExpression(IOperation primaryOperand, IOperation secondaryOperand, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+        public CoalesceExpression(IOperation expression, IOperation whenNull, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
             base(semanticModel, syntax, type, constantValue)
         {
-            PrimaryOperandImpl = primaryOperand;
-            SecondaryOperandImpl = secondaryOperand;
+            ExpressionImpl = expression;
+            WhenNullImpl = whenNull;
         }
 
-        protected override IOperation PrimaryOperandImpl { get; }
-        protected override IOperation SecondaryOperandImpl { get; }
+        protected override IOperation ExpressionImpl { get; }
+        protected override IOperation WhenNullImpl { get; }
     }
 
     /// <summary>
     /// Represents a null-coalescing expression.
     /// </summary>
-    internal sealed partial class LazyNullCoalescingExpression : BaseNullCoalescingExpression, INullCoalescingExpression
+    internal sealed partial class LazyCoalesceExpression : BaseCoalesceExpression, ICoalesceExpression
     {
-        private readonly Lazy<IOperation> _lazyPrimaryOperand;
-        private readonly Lazy<IOperation> _lazySecondaryOperand;
+        private readonly Lazy<IOperation> _lazyExpression;
+        private readonly Lazy<IOperation> _lazyWhenNull;
 
-        public LazyNullCoalescingExpression(Lazy<IOperation> primaryOperand, Lazy<IOperation> secondaryOperand, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(semanticModel, syntax, type, constantValue)
+        public LazyCoalesceExpression(Lazy<IOperation> expression, Lazy<IOperation> whenNull, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(semanticModel, syntax, type, constantValue)
         {
-            _lazyPrimaryOperand = primaryOperand ?? throw new System.ArgumentNullException(nameof(primaryOperand));
-            _lazySecondaryOperand = secondaryOperand ?? throw new System.ArgumentNullException(nameof(secondaryOperand));
+            _lazyExpression = expression ?? throw new System.ArgumentNullException(nameof(expression));
+            _lazyWhenNull = whenNull ?? throw new System.ArgumentNullException(nameof(whenNull));
         }
 
-        protected override IOperation PrimaryOperandImpl => _lazyPrimaryOperand.Value;
+        protected override IOperation ExpressionImpl => _lazyExpression.Value;
 
-        protected override IOperation SecondaryOperandImpl => _lazySecondaryOperand.Value;
+        protected override IOperation WhenNullImpl => _lazyWhenNull.Value;
     }
 
     /// <summary>

src/Compilers/Core/Portable/Operations/INullCoalescingExpression.cs → src/Compilers/Core/Portable/Operations/ICoalesceExpression.cs

@@ -11,16 +11,16 @@ namespace Microsoft.CodeAnalysis.Semantics
     /// This interface is reserved for implementation by its associated APIs. We reserve the right to
     /// change it in the future.
     /// </remarks>
-    public interface INullCoalescingExpression : IOperation
+    public interface ICoalesceExpression : IOperation
     {
         /// <summary>
         /// Value to be unconditionally evaluated.
         /// </summary>
-        IOperation PrimaryOperand { get; }
+        IOperation Expression { get; }
         /// <summary>
-        /// Value to be evaluated if Primary evaluates to null/Nothing.
+        /// Value to be evaluated if <see cref="Expression"/> evaluates to null/Nothing.
         /// </summary>
-        IOperation SecondaryOperand { get; }
+        IOperation WhenNull { get; }
     }
 }
 

src/Compilers/Core/Portable/Operations/OperationCloner.cs

@@ -274,9 +274,9 @@ public override IOperation VisitConditionalChoiceExpression(IConditionalChoiceEx
             return new ConditionalChoiceExpression(Visit(operation.Condition), Visit(operation.IfTrueValue), Visit(operation.IfFalseValue), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
-        public override IOperation VisitNullCoalescingExpression(INullCoalescingExpression operation, object argument)
+        public override IOperation VisitCoalesceExpression(ICoalesceExpression operation, object argument)
         {
-            return new NullCoalescingExpression(Visit(operation.PrimaryOperand), Visit(operation.SecondaryOperand), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
+            return new CoalesceExpression(Visit(operation.Expression), Visit(operation.WhenNull), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
         public override IOperation VisitIsTypeExpression(IIsTypeExpression operation, object argument)

src/Compilers/Core/Portable/Operations/OperationKind.cs

@@ -96,8 +96,8 @@ public enum OperationKind
         BinaryOperatorExpression = 0x10e,
         /// <summary>Indicates an <see cref="IConditionalChoiceExpression"/>.</summary>
         ConditionalChoiceExpression = 0x10f,
-        /// <summary>Indicates an <see cref="INullCoalescingExpression"/>.</summary>
-        NullCoalescingExpression = 0x110,
+        /// <summary>Indicates an <see cref="ICoalesceExpression"/>.</summary>
+        CoalesceExpression = 0x110,
         /// <summary>Indicates an <see cref="ILambdaExpression"/>.</summary>
         LambdaExpression = 0x111,
         /// <summary>Indicates an <see cref="IObjectCreationExpression"/>.</summary>

src/Compilers/Core/Portable/Operations/OperationVisitor.cs

@@ -270,7 +270,7 @@ public virtual void VisitConditionalChoiceExpression(IConditionalChoiceExpressio
             DefaultVisit(operation);
         }
 
-        public virtual void VisitNullCoalescingExpression(INullCoalescingExpression operation)
+        public virtual void VisitCoalesceExpression(ICoalesceExpression operation)
         {
             DefaultVisit(operation);
         }
@@ -740,7 +740,7 @@ public virtual TResult VisitConditionalChoiceExpression(IConditionalChoiceExpres
             return DefaultVisit(operation, argument);
         }
 
-        public virtual TResult VisitNullCoalescingExpression(INullCoalescingExpression operation, TArgument argument)
+        public virtual TResult VisitCoalesceExpression(ICoalesceExpression operation, TArgument argument)
         {
             return DefaultVisit(operation, argument);
         }

src/Compilers/Core/Portable/PublicAPI.Unshipped.txt

@@ -101,7 +101,7 @@ Microsoft.CodeAnalysis.OperationKind.MemberInitializerExpression = 289 -> Micros
 Microsoft.CodeAnalysis.OperationKind.MethodBindingExpression = 265 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.NameOfExpression = 291 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.None = 0 -> Microsoft.CodeAnalysis.OperationKind
-Microsoft.CodeAnalysis.OperationKind.NullCoalescingExpression = 272 -> Microsoft.CodeAnalysis.OperationKind
+Microsoft.CodeAnalysis.OperationKind.CoalesceExpression = 272 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.ObjectCreationExpression = 274 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.ObjectOrCollectionInitializerExpression = 288 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.OmittedArgumentExpression = 768 -> Microsoft.CodeAnalysis.OperationKind
@@ -512,9 +512,9 @@ Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression.IsVirtual.get -> bool
 Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression.Method.get -> Microsoft.CodeAnalysis.IMethodSymbol
 Microsoft.CodeAnalysis.Semantics.INameOfExpression
 Microsoft.CodeAnalysis.Semantics.INameOfExpression.Argument.get -> Microsoft.CodeAnalysis.IOperation
-Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression
-Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression.PrimaryOperand.get -> Microsoft.CodeAnalysis.IOperation
-Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression.SecondaryOperand.get -> Microsoft.CodeAnalysis.IOperation
+Microsoft.CodeAnalysis.Semantics.ICoalesceExpression
+Microsoft.CodeAnalysis.Semantics.ICoalesceExpression.Expression.get -> Microsoft.CodeAnalysis.IOperation
+Microsoft.CodeAnalysis.Semantics.ICoalesceExpression.WhenNull.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression
 Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression.Constructor.get -> Microsoft.CodeAnalysis.IMethodSymbol
 Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression.Initializer.get -> Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression
@@ -827,7 +827,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitLockStatement(Mic
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitMemberInitializerExpression(Microsoft.CodeAnalysis.Semantics.IMemberInitializerExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitMethodBindingExpression(Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitNameOfExpression(Microsoft.CodeAnalysis.Semantics.INameOfExpression operation) -> void
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitNullCoalescingExpression(Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression operation) -> void
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitCoalesceExpression(Microsoft.CodeAnalysis.Semantics.ICoalesceExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitObjectCreationExpression(Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitObjectOrCollectionInitializerExpression(Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitOmittedArgumentExpression(Microsoft.CodeAnalysis.Semantics.IOmittedArgumentExpression operation) -> void
@@ -917,7 +917,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.Vi
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitMemberInitializerExpression(Microsoft.CodeAnalysis.Semantics.IMemberInitializerExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitMethodBindingExpression(Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitNameOfExpression(Microsoft.CodeAnalysis.Semantics.INameOfExpression operation, TArgument argument) -> TResult
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitNullCoalescingExpression(Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression operation, TArgument argument) -> TResult
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitCoalesceExpression(Microsoft.CodeAnalysis.Semantics.ICoalesceExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitObjectCreationExpression(Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitObjectOrCollectionInitializerExpression(Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitOmittedArgumentExpression(Microsoft.CodeAnalysis.Semantics.IOmittedArgumentExpression operation, TArgument argument) -> TResult