[TypeScript] Can't infer type from `switch` and conditions

[CrazyboyQCD]

Consider code like this, lsp can't infer that a and b are any[] while the if can:

function equal(a: object, b: object) {
    switch ([true, true]) {
        case [Array.isArray(a), Array.isArray(b)]: {
            if (a.length !== b.length) {
                return false;
            }
            // ...
            return true;
        }
        // ...
        default: return false;
    }
}

[RyanCavanaugh]

This is not common enough to warrant supporting