Tracking invalid type assertions

[ghost]

Before we had no-object-literal-type-assertion applied, there were a lot of suspicious casts.
These have all been labeled with comments containing the text GH#18217.

[WORMSS]

So.. I kinda hit this today on
https://github.com/microsoft/TypeScript/blob/master/src/services/services.ts#L265

[edsrzf]

I've run into an exception thrown by this line, which has a comment referencing this issue:

TypeScript/src/services/codefixes/fixCannotFindModule.ts

Line 55 in 6bcb6bb

: (host.isKnownTypesPackageName!(packageName) ? getTypesPackageName(packageName) : undefined); // TODO: GH#18217

What's the best way to proceed? It looks like it would be relatively straightforward to add a check, but do I need to create a repro case to show it's a real issue? Should I open another issue and link to this one? Please advise.

[RyanCavanaugh]

This issue was a catch-all for eventually removing every postfix !. Please open a new issue outlining how to repro the problem you encountered. Thanks!

[mjz19910]

got an undefined in tsserver version 4.5.20210901

/**
@type {PropType<PropType<X,'prototype'>,'get'>}
*/
var error;

when you change a character in "prototype" or "get" and wait for type inference to activate, then this error appears in the devtools in code-insiders

getTypeParametersForTypeReference return undefined, that then causes this error

Cannot read property '1' of undefined
TypeError: Cannot read property '1' of undefined
at getTypeArgumentConstraint (c:\Users\matth.vscode-insiders\extensions\ms-vscode.vscode-typescript-next-4.5.20210901\node_modules\typescript\lib\tsserver.js:76890:73)
at Object.getTypeArgumentConstraint (c:\Users\matth.vscode-insiders\extensions\ms-vscode.vscode-typescript-next-4.5.20210901\node_modules\typescript\lib\tsserver.js:46205:32)
at getStringLiteralCompletionEntries (c:\Users\matth.vscode-insiders\extensions\ms-vscode.vscode-typescript-next-4.5.20210901\node_modules\typescript\lib\tsserver.js:125267:108)
at Object.getStringLiteralCompletions (c:\Users\matth.vscode-insiders\extensions\ms-vscode.vscode-typescript-next-4.5.20210901\node_modules\typescript\lib\tsserver.js:125173:35)

[dannymcgee]

It looks like custom transformers (at least those hooked into the before phase) can't successfully create new get/set accessor nodes due to an invalid non-null assertion at the very top of compiler > checker > createTypeChecker > createResolver > getAllAccessorDeclarations. Reproduced in 4.8.4, but the assertion is still there on main currently.

[jakebailey]

@dannymcgee Would you mind filing a new issue for that, especially if you have a simple transformer that shows the bug? We can add those as unit tests.

(As with #18217 (comment) this issue isn't really the right place to report isuses.)