Cannot read property 'length' of undefined

[elibarzilay]

Imported from microsoft/tsserverfuzzer#314

Repo Name: https://github.com/yarnpkg/yarn.git

Revision: 3119382885ea373d3c13d6a846de743eca8c914b

TypeScript Version: 4.3.0-dev.20210410

Commands:

{"response":[],"responseRequired":true}
{"command":"format","arguments":{"endLine":3,"endOffset":1,"line":3,"offset":1,"file":"D:/local/Temp/fuzzerWorkingDir/yarn/src/util/normalize-manifest/licenses.js","options":{}},"type":"request","seq":26}
{"response":[],"responseRequired":true}
{"command":"getCodeFixes","arguments":{"errorCodes":[1],"startLine":3,"startOffset":1,"endLine":3,"endOffset":1,"file":"D:/local/Temp/fuzzerWorkingDir/yarn/src/util/normalize-manifest/licenses.js"},"type":"request","seq":27}
{"response":[],"responseRequired":true}
{"command":"getApplicableRefactors","arguments":{"startLine":3,"startOffset":1,"endLine":3,"endOffset":1,"file":"D:/local/Temp/fuzzerWorkingDir/yarn/src/util/normalize-manifest/licenses.js"},"type":"request","seq":27}
{"response":[{"name":"Convert export","description":"Convert default export to named export","actions":[{"name":"Convert default export to named export","description":"Convert default export to named export","kind":"refactor.rewrite.export.named"}]}],"responseRequired":true}
{"command":"getApplicableRefactors","arguments":{"startPosition":30,"endPosition":31,"file":"D:/local/Temp/fuzzerWorkingDir/yarn/src/util/normalize-manifest/licenses.js"},"type":"request","seq":28}
{"response":[{"name":"Convert export","description":"Convert default export to named export","actions":[{"name":"Convert default export to named export","description":"Convert default export to named export","kind":"refactor.rewrite.export.named"}]}],"responseRequired":true}
{"command":"getEditsForRefactor-full","arguments":{"refactor":"Convert export","action":"Convert default export to named export","startPosition":30,"endPosition":31,"file":"D:/local/Temp/fuzzerWorkingDir/yarn/src/util/normalize-manifest/licenses.js"},"type":"request","seq":29}
(Showing last 10 of 96829 commands)

Code (src\util\normalize-manifest\licenses.js):

  /* @flow */
  
  /* eslint-disable max-len */
//                 ^
  
  /**

Hash: 118a1b4b6ad0276ad98f166743ace4f4
Stack trace:

Cannot read property 'length' of undefined
    at escapeLeadingUnderscores (tsserverlibrary.js:12173:28)
    at createBaseIdentifier (tsserverlibrary.js:21609:35)
    at createIdentifier (tsserverlibrary.js:21621:24)
    at makeExportSpecifier (tsserverlibrary.js:148021:143)
    at changeExport (tsserverlibrary.js:147894:32)
    at doChange (tsserverlibrary.js:147886:13)
    at <anonymous> (tsserverlibrary.js:147833:94)
    at ChangeTracker.with (tsserverlibrary.js:138743:17)
    at getEditsForAction (tsserverlibrary.js:147833:62)
    at getEditsForRefactor (tsserverlibrary.js:139972:41)