public void Verify(VerificationContext context, ASTNode node)
{
var expressionType = context.ResolveExpressionRef(node.GetAttribute<string>("libraryName"), node.GetAttribute<string>("name"));
if (expressionType.Expression.ResultType == null)
{
throw new InvalidOperationException("Invalid forward reference.");
}
node.ResultType = expressionType.Expression.ResultType;
}