TS looses previously determined type

[bpasero]

See how errorWithActions becomes any[] because Array.isArray() is used:

https://github.com/microsoft/vscode/blob/cffd590665a0271a05ad90dbb3c708d156c3008b/src/vs/workbench/browser/parts/editor/editorPanes.ts#L155

https://github.com/microsoft/vscode/blob/cffd590665a0271a05ad90dbb3c708d156c3008b/src/vs/workbench/browser/parts/editor/editorPanes.ts#L162

[IllusionMH]

Looks like not the first case for Array.isArray and IAction combo
#41889
#39258

[mjbvz]

Self contained example:

let errorActions: readonly string[] | undefined = undefined;
if (Array.isArray(errorActions)) {
    // check errorActions here
    console.log(errorActions)
}

[andrewbranch]

Duplicate of #17002

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.