namespace Microsoft.CodeAnalysis.Operations
{
    public enum OperationKind
    {
+       /// <summary>Indicates an <see cref="IInterpolatedStringHandlerCreationOperation"/>.</summary>
+       InterpolatedStringHandler = 0x72,
+       /// <summary>Indicates an <see cref="IInterpolatedStringAdditionOperation"/>.</summary>
+       InterpolatedStringAddition = 0x73,
+       /// <summary>Indicates an <see cref="IInterpolatedStringAppendOperation"/>. </summary>
+       InterpolatedStringAppendLiteral = 0x74,
+       /// <summary>Indicates an <see cref="IInterpolatedStringAppendOperation"/>. This append is of an interpolation component</summary>
+       InterpolatedStringAppendFormatted = 0x75,
+       /// <summary>Indicates an <see cref="IInterpolatedStringHandlerArgumentPlaceholderOperation"/>.</summary>
+       InterpolatedStringHandlerArgumentPlaceholder = 0x76,
    }

+   /// <summary>
+   /// Represents an interpolated string converted to a custom interpolated string handler type.
+   /// </summary>
+   public interface IInterpolatedStringHandlerCreationOperation : IOperation
+   {
+       /// <summary>
+       /// The construction of the interpolated string handler instance. This can be an <see cref="IObjectCreationOperation" /> for valid code, and
+       /// <see cref="IDynamicObjectCreationOperation" /> or <see cref="IInvalidOperation" /> for invalid code.
+       /// </summary>
+       IOperation HandlerCreation { get; }
+       /// <summary>
+       /// True if the last parameter of <see cref="HandlerCreation" /> is an out <see langword="bool" /> parameter that will be checked before executing the code in
+       /// <see cref="Content" />. False otherwise.
+       /// </summary>
+       bool HandlerCreationHasSuccessParameter { get; }
+       /// <summary>
+       /// True if the AppendLiteral or AppendFormatted calls in <see cref="Parts" /> return <see langword="bool" />. When that is true, each part will be conditional
+       /// on the return of the part before it, only being executed when the Append call returns true. False otherwise.
+       /// </summary>
+       /// <remarks>
+       /// when this is true and <see cref="HandlerCreationHasSuccessParameter" /> is true, then the first part in <see cref="Parts" /> is conditionally run. If this is
+       /// true and <see cref="HandlerCreationHasSuccessParameter" /> is false, then the first part is unconditionally run.
+       /// <br />
+       /// Just because this is true or false does not guarantee that all Append calls actually do return boolean values, as there could be dynamic calls or errors.
+       /// It only governs what the compiler was expecting, based on the first calls it did see.
+       /// </remarks>
+       bool HandlerAppendCallsReturnBool { get; }
+       /// <summary>
+       /// The interpolated string expression or addition operation that makes up the content of this string. This is either an <see cref="IInterpolatedStringOperation" />
+       /// or an <see cref="IInterpolatedStringAdditionOperation" /> operation.
+       /// </summary>
+       IOperation Content { get; }
+   }
+   /// <summary>
+   /// Represents an addition of multiple interpolated string literals being converted to an interpolated string handler type.
+   /// </summary>
+   public interface IInterpolatedStringAdditionOperation : IOperation
+   {
+       /// <summary>
+       /// The interpolated string expression or addition operation on the left side of the operator. This is either an <see cref="IInterpolatedStringOperation" />
+       /// or an <see cref="IInterpolatedStringAdditionOperation" /> operation.
+       /// </summary>
+       IOperation Left { get; }
+       /// <summary>
+       /// The interpolated string expression or addition operation on the right side of the operator. This is either an <see cref="IInterpolatedStringOperation" />
+       /// or an <see cref="IInterpolatedStringAdditionOperation" /> operation.
+       /// </summary>
+       IOperation Right { get; }
+   }
+   /// <summary>
+   /// Represents a call to either AppendLiteral or AppendFormatted as part of an interpolated string handler conversion.
+   /// </summary>
+   public interface IInterpolatedStringAppendOperation : IInterpolatedStringContentOperation
+   {
+       /// <summary>
+       /// If this interpolated string is subject to an interpolated string handler conversion, the construction of the interpolated string handler instance.
+       /// This can be an IInvocationOperation or IDynamicInvocationOperation for valid code, and IInvalidOperation for invalid code.
+       /// </summary>
+       IOperation? AppendCall { get; }
+   }
+   /// <summary>
+   /// Represents an argument from the method call, indexer access, or constructor invocation that is creating the containing <see cref="IInterpolatedStringHandlerCreationOperation" />
+   /// </summary>
+   public interface IInterpolatedStringHandlerArgumentPlaceholderOperation : IOperation
+   {
+       /// <summary>
+       /// The index of the argument of the method call containing the interpolated string handler conversion this placeholder is referencing. -1 if
+       /// <see cref="IsContainingMethodReceiver" /> or if the argument was not resolved.
+       /// </summary>
+       int ArgumentIndex { get; }
+       /// <summary>
+       /// True if this placeholder represents the instance receiver of the method call containing the interpolated string handler conversion.
+       /// </summary>
+       /// <remarks>
+       /// Extension method receivers are not treated as receivers here: they have an <see cref="ArgumentIndex" /> of 0.
+       /// </remarks>
+       bool IsContainingMethodReceiver { get; }
+   }

    public enum InstanceReferenceKind
    {
+       /// <summary>
+       /// Reference to the interpolated string handler instance created as part of a parent interpolated string handler conversion.
+       /// </summary>
+       InterpolatedStringHandler
    }
}

namespace Microsoft.CodeAnalysis.Operations
{
+    public enum InterpolatedStringArgumentPlaceholderKind
+    {
+        Argument,
+        ContainingMethodReceiver,
+        TrailingValidityParameter,
+    }
    public interface IInterpolatedStringHandlerArgumentPlaceholderOperation : IOperation
    {
        /// <summary>
        /// The index of the argument of the method call containing the interpolated string handler conversion this placeholder is referencing. -1 if <see cref="PlaceholderKind" /> is
        /// anything other than <see cref="InterpolatedStringArgumentPlaceholderKind.Argument" />.
        /// </summary>
        int ArgumentIndex { get; }

+        InterpolatedStringArgumentPlaceholderKind PlaceholderKind { get; }
    }
}