Language server debug failure - Did not expect GetAccessor to have an Identifier in its trivia

[TheWyo]

Bug Report

🔎 Search Terms

• auto complete
• suggestions
• snippets
• language server

🕗 Version & Regression Information

• This changed between versions 4.6.3 and 4.6.4

⏯ Playground Link

N/A, requires npm dependency

💻 Code

Code sample unfortunately uses an external library as I've not been able to nail down an exact repro, but this issue only seems to occur in >=4.6.4 so I think this is less likely to be a purely type definition issue. Also reproduces in the latest dev version (at posting, 4.9.0-dev.20220823). I've also seen this error with SetAccessor instead of GetAccessor in similar situations.

Repro steps

1. New project/workspace in vscode
2. npm init -y.
3. npm i @pixi/display@6.5.1
4. npm i -D typescript@4.6.3
5. Create the following file as src/index.ts:

import { DisplayObject } from "@pixi/display";

class A extends DisplayObject
{
	
}

6. Place cursor within the class definition
7. CTRL+Space to get suggestions/auto complete/snippets
8. Change TS version to 4.6.4, repeat steps 6 & 7.
9. No suggestions/auto complete/snippets this time.

🙁 Actual behavior

No suggestions/snippets provided, extension host log contains the following:

[2022-08-23 11:55:41.066] [exthost] [error] Error: <semantic> TypeScript Server Error (4.9.0-dev.20220823)
Debug Failure. Did not expect GetAccessor to have an Identifier in its trivia
Error: Debug Failure. Did not expect GetAccessor to have an Identifier in its trivia
    at addSyntheticNodes (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:166443:30)
    at processNode (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:166416:13)
    at visitNode (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:30934:24)
    at forEachChildInGetAccessor (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:31105:17)
    at Object.forEachChild (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:31714:47)
    at NodeObject.forEachChild (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:166397:23)
    at createChildren (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:166431:14)
    at NodeObject.getChildren (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:166374:56)
    at find (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:129452:30)
    at Object.findPrecedingToken (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:129445:22)
    at formatSpanWorker (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:149386:44)
    at d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:149309:140
    at Object.getFormattingScanner (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:147936:23)
    at Object.formatNodeGivenIndentation (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:149309:31)
    at d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:134870:42
    at Object.flatMap (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:524:25)
    at Object.printAndFormatSnippetList (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:134868:34)
    at getEntryForMemberCompletion (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:134672:42)
    at createCompletionEntry (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:134492:23)
    at getCompletionEntriesFromSymbols (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:134997:29)
    at completionInfoFromData (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:134304:31)
    at Object.getCompletionsAtPosition (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:134164:36)
    at Object.getCompletionsAtPosition (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:167677:35)
    at IpcIOSession.Session.getCompletions (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:179809:64)
    at Session.handlers.ts.Map.ts.getEntries._a.<computed> (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:178482:61)
    at d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:180542:96
    at IpcIOSession.Session.executeWithRequestId (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:180533:28)
    at IpcIOSession.Session.executeCommand (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:180542:41)
    at IpcIOSession.Session.onMessage (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:180570:35)
    at process.<anonymous> (d:\Temp\snippetbugtest\node_modules\typescript\lib\tsserver.js:184736:31)
    at process.emit (node:events:390:28)
    at emit (node:internal/child_process:917:12)
    at processTicksAndRejections (node:internal/process/task_queues:84:21)
	at Function.create (c:\Users\Russell.Speke\AppData\Local\Programs\Microsoft VS Code\resources\app\extensions\typescript-language-features\dist\extension.js:1:509517)
	at dispatchResponse (c:\Users\Russell.Speke\AppData\Local\Programs\Microsoft VS Code\resources\app\extensions\typescript-language-features\dist\extension.js:1:503365)
	at dispatchMessage (c:\Users\Russell.Speke\AppData\Local\Programs\Microsoft VS Code\resources\app\extensions\typescript-language-features\dist\extension.js:1:502233)
	at ChildProcess.<anonymous> (c:\Users\Russell.Speke\AppData\Local\Programs\Microsoft VS Code\resources\app\extensions\typescript-language-features\dist\extension.js:1:501718)
	at ChildProcess.emit (node:events:390:28)
	at emit (node:internal/child_process:917:12)
	at processTicksAndRejections (node:internal/process/task_queues:84:21)

🙂 Expected behavior

Auto complete/snippets etc should work as normal.

[DanielRosenwasser]

Minimal repro

declare class B {
    get mask(): any;
    set mask(value: any);
}
class A extends B {
    /**/
}

Request completions at /**/ and this gives back

Details

Error: Debug Failure. Did not expect GetAccessor to have an Identifier in its trivia
    at addSyntheticNodes (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:166443:30)
    at processNode (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:166416:13)
    at visitNode (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:30934:24)
    at forEachChildInGetAccessor (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:31105:17)
    at Object.forEachChild (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:31714:47)
    at NodeObject.forEachChild (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:166397:23)
    at createChildren (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:166431:14)
    at NodeObject.getChildren (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:166374:56)
    at find (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:129452:30)
    at Object.findPrecedingToken (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:129445:22)
    at formatSpanWorker (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:149386:44)
    at UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:149309:140
    at Object.getFormattingScanner (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:147936:23)
    at Object.formatNodeGivenIndentation (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:149309:31)
    at UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:134870:42
    at Object.flatMap (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:524:25)
    at Object.printAndFormatSnippetList (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:134868:34)
    at getEntryForMemberCompletion (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:134672:42)
    at createCompletionEntry (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:134492:23)
    at getCompletionEntriesFromSymbols (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:134997:29)
    at completionInfoFromData (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:134304:31)
    at Object.getCompletionsAtPosition (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:134164:36)
    at Object.getCompletionsAtPosition (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:167677:35)
    at Session.getCompletions (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:179809:64)
    at Session.handlers.ts.Map.ts.getEntries._a.<computed> (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:178482:61)
    at UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:180542:96
    at Session.executeWithRequestId (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:180533:28)
    at Session.executeCommand (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:180542:41)
    at Session.onMessage (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:180570:35)
    at process.<anonymous> (UserDir/.vscode-insiders/extensions/ms-vscode.vscode-typescript-next-4.9.20220823/node_modules/typescript/lib/tsserver.js:184736:31)
    at process.emit (node:events:526:28)
    at emit (node:internal/child_process:938:14)
    at process.processTicksAndRejections (node:internal/process/task_queues:84:21)

Same applies for the other ordering with a set accessor.

declare class B {
    set mask(value: any);
    get mask(): any;
}
class A extends B {
    /**/
}

[TheWyo]

I could've sworn I tried a setup that simple while trying to figure out a repro and it worked...
Maybe I forgot to restart the TS server in vscode once after changing version when trying to find when this broke. Thanks for confirming!

[DanielRosenwasser]

I believe that this is similar to #44301 in spirit - we do a bunch of node-sharing in the language service, but we assume that no step down-the-line is going to re-assign positions to each node for formatting. My guess is from looking at this code which doesn't do any deep cloning:

TypeScript/src/services/codefixes/helpers.ts

Lines 124 to 143 in e675ea8

	for (const accessor of orderedAccessors) {
	if (isGetAccessorDeclaration(accessor)) {
	addClassElement(factory.createGetAccessorDeclaration(
	modifiers,
	name,
	emptyArray,
	typeNode,
	ambient ? undefined : body || createStubbedMethodBody(quotePreference)));
	}
	else {
	Debug.assertNode(accessor, isSetAccessorDeclaration, "The counterpart to a getter should be a setter");
	const parameter = getSetAccessorValueParameter(accessor);
	const parameterName = parameter && isIdentifier(parameter.name) ? idText(parameter.name) : undefined;
	addClassElement(factory.createSetAccessorDeclaration(
	modifiers,
	name,
	createDummyParameters(1, [parameterName], [typeNode], 1, /*inJs*/ false),
	ambient ? undefined : body || createStubbedMethodBody(quotePreference)));
	}
	}

versus the subsequent code for methods:

TypeScript/src/services/codefixes/helpers.ts

Lines 168 to 171 in e675ea8

	for (const signature of signatures) {
	// Ensure nodes are fresh so they can have different positions when going through formatting.
	outputMethod(quotePreference, signature, getSynthesizedDeepClones(modifiers, /*includeTrivia*/ false), getSynthesizedDeepClone(name, /*includeTrivia*/ false));
	}

Plus the fact that when I debugged this, the first accessor's Identifier node has its position set past the accessor itself.

Tossing a few getSynthesizedDeepClones was not enough to fix it completely, though I assume that it's part of the eventual fix.

[DanielRosenwasser]

Thank you Oleksandr Tarasiuk (@a-tarasyuk)!