/// <summary>
/// Rewrites the given interpolated string to the set of handler creation and Append calls, returning an array builder of the append calls and the result
/// local temp.
/// </summary>
/// <remarks>Caller is responsible for freeing the ArrayBuilder</remarks>
private InterpolationHandlerResult RewriteToInterpolatedStringHandlerPattern(InterpolatedStringHandlerData data, ImmutableArray <BoundExpression> parts, SyntaxNode syntax)
{
Debug.Assert(parts.All(static p => p is BoundCall or BoundDynamicInvocation));
public static UncommonData InterpolatedStringHandlerAddition(InterpolatedStringHandlerData data) => new UncommonData(