namespace Microsoft.CodeAnalysis.CSharp
{
    public enum SyntaxKind : ushort
    {
+        CollectionExpression = 9076,
+        ExpressionElement = 9077,
+        SpreadElement = 9078,
    }

    public static class SyntaxFactory
    {
+        public static CollectionExpressionSyntax CollectionExpression(
+            SyntaxToken openBracketToken,
+            SeparatedSyntaxList<CollectionElementSyntax> elements,
+            SyntaxToken closeBracketToken);
+        public static CollectionExpressionSyntax CollectionExpression(
+            SeparatedSyntaxList<CollectionElementSyntax> elements = default);
+        public static ExpressionElementSyntax ExpressionElement(
+            ExpressionSyntax expression);
+        public static SpreadElementSyntax SpreadElement(
+            SyntaxToken operatorToken,
+            ExpressionSyntax expression);
+        public static SpreadElementSyntax SpreadElement(
+            ExpressionSyntax expression);
    }
}

namespace Microsoft.CodeAnalysis.CSharp.Syntax
{
+    public sealed class CollectionExpressionSyntax : ExpressionSyntax
+    {
+        public SyntaxToken OpenBracketToken { get; }
+        public SeparatedSyntaxList<CollectionElementSyntax> Elements { get; }
+        public SyntaxToken CloseBracketToken { get; }
+        public CollectionExpressionSyntax Update(
+            SyntaxToken openBracketToken,
+            SeparatedSyntaxList<CollectionElementSyntax> elements,
+            SyntaxToken closeBracketToken);
+        public CollectionExpressionSyntax WithOpenBracketToken(
+            SyntaxToken openBracketToken);
+        public CollectionExpressionSyntax WithElements(
+            SeparatedSyntaxList<CollectionElementSyntax> elements);
+        public CollectionExpressionSyntax WithCloseBracketToken(
+            SyntaxToken closeBracketToken);
+        public CollectionExpressionSyntax AddElements(
+            params CollectionElementSyntax[] items);
+    }

+    public abstract class CollectionElementSyntax : CSharpSyntaxNode
+    {
+    }

+    public sealed class ExpressionElementSyntax : CollectionElementSyntax
+    {
+        public ExpressionSyntax Expression { get; }
+        public ExpressionElementSyntax Update(
+            ExpressionSyntax expression);
+        public ExpressionElementSyntax WithExpression(
+            ExpressionSyntax expression);
+    }

+    public sealed class SpreadElementSyntax : CollectionElementSyntax
+    {
+        public SyntaxToken OperatorToken { get; }
+        public ExpressionSyntax Expression { get; }
+        public SpreadElementSyntax Update(
+            SyntaxToken operatorToken,
+            ExpressionSyntax expression);
+        public SpreadElementSyntax WithOperatorToken(
+            SyntaxToken operatorToken);
+        public SpreadElementSyntax WithExpression(
+            ExpressionSyntax expression);
+    }
}

~~namespace Microsoft.CodeAnalysis.CSharp~~
{
     public readonly struct Conversion
     {
+        public bool IsCollectionLiteral { get; }
     }
}

namespace Microsoft.CodeAnalysis.Operations
{
+    /// <summary>
+    /// Represents a collection literal.
+    /// <para>
+    ///   Current usage:
+    ///   (1) C# collection literal expression.
+    /// </para>
+    /// </summary>
+    public interface ICollectionLiteralOperation : IOperation
+    {
+        /// <summary>
+        /// Method to construct the collection instance.
+        /// </summary>
+        IMethodSymbol? ConstructMethod { get; }

+        /// <summary>
+        /// Collection literal elements.
+        /// </summary>
+        ImmutableArray<IOperation> Elements { get; }
+    }

+    /// <summary>
+    /// Represents a collection literal spread element.
+    /// <para>
+    ///   Current usage:
+    ///   (1) C# spread element.
+    /// </para>
+    /// </summary>
+    public interface ISpreadOperation : IOperation
+    {
+        /// <summary>
+        /// Collection value being spread.
+        /// </summary>
+        IOperation Collection { get; }
+    }
}