Refactorings with optional chaining fail

[spencersutton]

TypeScript Version: 3.8.0-dev.20191126

Search Terms: Extract refactorings

Code

function foo(bar?: number) {
	bar?.toString();
}

Select bar?.toString(); and try to use any of the extract refactorings in Visual Studio Code.

Expected behavior:
Refactorings work like they do without optional chaining.

Actual behavior:

<semantic> TypeScript Server Error (3.8.0-dev.20191126)
Debug Failure. False expression.
Error: Debug Failure. False expression.
    at getPos (tsserver.js:119431:22)
    at assignPositionsToNode (tsserver.js:120172:27)
    at visitNode (tsserver.js:70948:23)
    at Object.visitEachChild (tsserver.js:71165:117)
    at assignPositionsToNode (tsserver.js:120169:30)
    at visitNode (tsserver.js:70948:23)
    at Object.visitEachChild (tsserver.js:71175:53)
    at assignPositionsToNode (tsserver.js:120169:30)
    at visitNode (tsserver.js:70948:23)
    at Object.visitEachChild (tsserver.js:71261:224)
    at assignPositionsToNode (tsserver.js:120169:30)
    at Object.visitNodes (tsserver.js:70999:48)
    at assignPositionsToNodeArray (tsserver.js:120177:30)
    at Object.visitEachChild (tsserver.js:71263:63)
    at assignPositionsToNode (tsserver.js:120169:30)
    at visitNode (tsserver.js:70948:23)
    at Object.visitEachChild (tsserver.js:71229:111)
    at assignPositionsToNode (tsserver.js:120169:30)
    at getNonformattedText (tsserver.js:120153:56)
    at getFormattedTextOfNode (tsserver.js:120134:26)
    at format (tsserver.js:120117:52)
    at computeNewText (tsserver.js:120120:23)
    at tsserver.js:120090:89
    at Array.map (<anonymous>)
    at tsserver.js:120089:50
    at Array.map (<anonymous>)
    at Object.getTextChangesFromChanges (tsserver.js:120075:86)
    at ChangeTracker.getChanges (tsserver.js:120045:45)
    at extractConstantInScope (tsserver.js:127538:43)
    at getConstantExtractionAtIndex (tsserver.js:127134:24)
    at Object.getEditsForAction (tsserver.js:126727:28)
    at Object.getEditsForRefactor (tsserver.js:120662:41)
    at Proxy.getEditsForRefactor (tsserver.js:131547:32)
    at IOSession.Session.getEditsForRefactor (tsserver.js:140903:59)
    at Session.handlers.ts.createMapFromTemplate._a.<computed> (tsserver.js:139754:61)
    at tsserver.js:141141:88
    at IOSession.Session.executeWithRequestId (tsserver.js:141132:28)
    at IOSession.Session.executeCommand (tsserver.js:141141:33)
    at IOSession.Session.onMessage (tsserver.js:141164:35)
    at Interface.<anonymous> (tsserver.js:142479:27)
    at Interface.emit (events.js:200:13)
    at Interface._onLine (readline.js:314:10)
    at Interface._normalWrite (readline.js:459:12)
    at Socket.ondata (readline.js:170:10)
    at Socket.emit (events.js:200:13)
    at addChunk (_stream_readable.js:294:12)
    at readableAddChunk (_stream_readable.js:275:11)
    at Socket.Readable.push (_stream_readable.js:210:10)
    at Pipe.onStreamRead (internal/stream_base_commons.js:166:17)