private AggregateSymbol FindPredefinedType(ErrorHandling errorContext, string pszType, KAID aid, AggKindEnum aggKind, int arity, bool isRequired)
        {
            Debug.Assert(!string.IsNullOrEmpty(pszType)); // Shouldn't be the empty string!

            NamespaceOrAggregateSymbol bagCur = _pBSymmgr.GetRootNS();
            Name name = null;

            string[] nameParts = pszType.Split(s_nameSeparators);
            for (int i = 0, n = nameParts.Length; i < n; i++)
            {
                name = _pBSymmgr.GetNameManager().Add(nameParts[i]);

                if (i == n - 1)
                {
                    // This is the last component. Handle it special below.
                    break;
                }

                // first search for an outer type which is also predefined
                // this must be first because we always create a namespace for
                // outer names, even for nested types
                AggregateSymbol aggNext = _pBSymmgr.LookupGlobalSymCore(name, bagCur, symbmask_t.MASK_AggregateSymbol).AsAggregateSymbol();
                if (aggNext != null && aggNext.InAlias(aid) && aggNext.IsPredefined())
                {
                    bagCur = aggNext;
                }
                else
                {
                    // ... if no outer type, then search for namespaces
                    NamespaceSymbol nsNext     = _pBSymmgr.LookupGlobalSymCore(name, bagCur, symbmask_t.MASK_NamespaceSymbol).AsNamespaceSymbol();
                    bool            bIsInAlias = true;
                    if (nsNext == null)
                    {
                        bIsInAlias = false;
                    }
                    else
                    {
                        bIsInAlias = nsNext.InAlias(aid);
                    }
                    if (!bIsInAlias)
                    {
                        // Didn't find the namespace in this aid.
                        if (isRequired)
                        {
                            errorContext.Error(ErrorCode.ERR_PredefinedTypeNotFound, pszType);
                        }
                        return(null);
                    }
                    bagCur = nsNext;
                }
            }

            AggregateSymbol aggAmbig;
            AggregateSymbol aggBad;
            AggregateSymbol aggFound = FindPredefinedTypeCore(name, bagCur, aid, aggKind, arity, out aggAmbig, out aggBad);

            if (aggFound == null)
            {
                // Didn't find the AggregateSymbol.
                if (aggBad != null && (isRequired || aid == KAID.kaidGlobal && aggBad.IsSource()))
                {
                    errorContext.ErrorRef(ErrorCode.ERR_PredefinedTypeBadType, aggBad);
                }
                else if (isRequired)
                {
                    errorContext.Error(ErrorCode.ERR_PredefinedTypeNotFound, pszType);
                }
                return(null);
            }

            if (aggAmbig == null && aid != KAID.kaidGlobal)
            {
                // Look in kaidGlobal to make sure there isn't a conflicting one.
                AggregateSymbol tmp;
                AggregateSymbol agg2 = FindPredefinedTypeCore(name, bagCur, KAID.kaidGlobal, aggKind, arity, out aggAmbig, out tmp);
                Debug.Assert(agg2 != null);
                if (agg2 != aggFound)
                {
                    aggAmbig = agg2;
                }
            }

            return(aggFound);
        }