internal EnvDTE.CodeParameter AddParameter(EnvDTE.CodeElement parent, SyntaxNode containerNode, string name, object type, object position)
{
var typeSymbol = CodeModelService.GetTypeSymbol(type, this.GetSemanticModel(), containerNode.SpanStart);
var typeName = typeSymbol.GetEscapedFullName();
var parameterNode = CodeModelService.CreateParameterNode(CodeModelService.GetUnescapedName(name), typeName);
var insertionIndex = CodeModelService.PositionVariantToParameterInsertionIndex(position, containerNode, fileCodeModel: this);
var newNode = InsertParameter(containerNode, parameterNode, insertionIndex);
// Since parameters form part of the NodeKey for functions, delegates, and indexers,
// creating a CodeParameter hooked up to the correct parent is a little tricky. After
// the call to InsertParameter, the syntax tree has been updated, but not the NodeKey
// map or the NodeKey in the parent CodeParameter. If we delegate the creation of the
// CodeParameter to CodeModelService.CreateInternalCodeElement, it will attempt to
// look up an element in the NodeKey map based on the new syntax tree. This will fail,
// causing it to create a new, duplicate element for the parent. Later, when we
// reacquire the NodeKeys, the original element will get the proper NodeKey, while the
// duplicate will be updated to a meaningless NodeKey. Since the duplicate is the one
// being used by the CodeParameter, most operations on it will then fail.
// Instead, we need to have the parent passed in to us.
var parentObj = ComAggregate.GetManagedObject <AbstractCodeMember>(parent);
return(CodeParameter.Create(this.State, parentObj, CodeModelService.GetParameterName(newNode)));
}