scanTrivia from old LS keeps hitting error condition

[DanielRosenwasser]

While editing:

Error processing work item: 

Action description:

getCompletionsAtPosition('C:\Users\drosen\TypeScript\src\services\services.ts', 103657, false)

Script callstack:

Error: Invalid operation: undefined
   at scanTrivia (:17048:33)
   at trailingTrivia (:16795:13)
   at trailingTrivia (:16910:17)
   at withLeadingTrivia (:19122:13)
   at addSkippedTokenToTriviaArray (:21094:17)
   at addSkippedTokenAfterToken (:21089:17)
   at addSkippedTokenAfterNode (:21051:17)
   at addSkippedTokenAfterNodeOrToken (:20997:21)
   at addSkippedTokenToList (:22933:29)
   at abortParsingListOrMoveToNextToken (:22921:17)
   at parseSeparatedSyntaxListWorker (:22984:25)
   at parseSeparatedSyntaxList (:22908:17)
   at parseObjectLiteralExpression (:22617:17)
   at tryParsePrimaryExpression (:22431:25)
   at tryParseMemberExpressionOrHigher (:22266:17)
   at tryParseLeftHandSideExpressionOrHigher (:22318:21)
   at tryParsePostfixExpressionOrHigher (:22331:17)
   at tryParseUnaryExpressionOrHigher (:22223:25)
   at tryPars......

<truncated>

Things to investigate

• Why this happens
• Related issues
• Does this exist in old LS?