TypeError: Cannot read property 'kind' of undefined in 'areSameModule' during 'navtree'

[typescript-bot]

This issue comes from crash dumps in telemetry. We've tried to de-duplicate issues on a best-effort basis, comparing the sequence of methods called and the command requested while ignoring line numbers.
TypeScript version prefix: 3.8.3
VSCode version: 1.43.2
Command requested: navtree
Hitting sessions: 2099
Five line hash: 5f939d885584a54ff4b530bb3e868b4c
Stack:

    at areSameModule (tsserver.js:116719:27)
    at shouldReallyMerge (tsserver.js:116704:28)
    at tryMerge (tsserver.js:116686:17)
    at <anonymous> (tsserver.js:116584:25)
    at filterMutate (tsserver.js:384:17)
    at mergeChildren (tsserver.js:116560:16)
    at endNode (tsserver.js:116318:17)
    at rootNavigationBarNode (tsserver.js:116259:13)
    at getNavigationTree (tsserver.js:116223:38)
    at getNavigationTree (tsserver.js:135574:37)
    at Session.getNavigationTree (tsserver.js:145615:44)
    at _a.<computed> (tsserver.js:144481:61)
    at <anonymous> (tsserver.js:146003:88)
    at Session.executeWithRequestId (tsserver.js:145994:28)
    at Session.executeCommand (tsserver.js:146003:33)
    at Session.onMessage (tsserver.js:146027:35)
    at <anonymous> (tsserver.js:147342:27)
    at unknown (suppressed.js)
    at unknown (suppressed.js)
    at unknown (suppressed.js)
    at unknown (suppressed.js)
    at unknown (suppressed.js)
    at unknown (suppressed.js)
    at unknown (suppressed.js)
    at unknown (suppressed.js)
    at unknown (suppressed.js)

[typescript-bot]

Revised stack format and updated hash.

[typescript-bot]

This issue reproduced in the following context:
TypeScript version prefix: 4.1.2
VSCode version: 1.51.1
Command requested: navtree
Hitting sessions: 125
Five line hash: 5f939d885584a54ff4b530bb3e868b4c
Stack:

    at areSameModule (tsserver.js:125392:27)
    at shouldReallyMerge (tsserver.js:125377:28)
    at tryMerge (tsserver.js:125359:17)
    at <anonymous> (tsserver.js:125257:25)
    at filterMutate (tsserver.js:432:17)
    at mergeChildren (tsserver.js:125233:16)
    at endNode (tsserver.js:124978:17)
    at addNodeWithRecursiveChild (tsserver.js:124987:13)
    at addChildrenRecursively (tsserver.js:125081:21)
    at visitNode (tsserver.js:27655:24)
    at forEachChild (tsserver.js:27941:24)
    at addChildrenRecursively (tsserver.js:125227:24)
    at visitNodes (tsserver.js:27664:30)
    at forEachChild (tsserver.js:27901:24)
    at addChildrenRecursively (tsserver.js:125227:24)
    at addNodeWithRecursiveChild (tsserver.js:124986:13)
    at addChildrenRecursively (tsserver.js:125014:25)
    at visitNodes (tsserver.js:27664:30)
    at forEachChild (tsserver.js:27840:24)
    at addChildrenRecursively (tsserver.js:125227:24)
    at addNodeWithRecursiveChild (tsserver.js:124986:13)
    at addChildrenRecursively (tsserver.js:125068:25)
    at visitNodes (tsserver.js:27664:30)
    at forEachChild (tsserver.js:27910:24)
    at addChildrenRecursively (tsserver.js:125227:24)
    at visitNode (tsserver.js:27655:24)
    at forEachChild (tsserver.js:27908:21)
    at addChildrenRecursively (tsserver.js:125227:24)
    at rootNavigationBarNode (tsserver.js:124916:17)
    at getNavigationTree (tsserver.js:124882:38)
    at getNavigationTree (tsserver.js:146933:37)
    at Session.getNavigationTree (tsserver.js:157830:44)
    at _a.<computed> (tsserver.js:156624:61)
    at <anonymous> (tsserver.js:158276:88)
    at Session.executeWithRequestId (tsserver.js:158267:28)
    at Session.executeCommand (tsserver.js:158276:33)
    at Session.onMessage (tsserver.js:158300:35)
    at <anonymous> (tsserver.js:160510:27)
    at unknown (suppressed.js:223:5)
    at unknown (suppressed.js:315:10)
    at unknown (suppressed.js:460:12)
    at unknown (suppressed.js:172:10)
    at unknown (suppressed.js:223:5)
    at unknown (suppressed.js:309:12)
    at unknown (suppressed.js:290:11)
    at unknown (suppressed.js:224:10)
    at unknown (suppressed.js:181:23)