Safe guard for elements of fixed array yields error when trying to use whole array

[G07cha]

TypeScript Version: 3.6.0-dev.20190730

Search Terms:

• Type guard for items of fixed array
• Validating items of fixed array

Code

const foo: [Date | undefined, Date | undefined] = [undefined, new Date()]

const strictDatePair = (dates: [Date, Date]) => console.log(dates)

if (foo[0] instanceof Date && foo[1] instanceof Date) {
    strictDatePair([foo[0], foo[1]]) // ok
}

if (foo[0] instanceof Date && foo[1] instanceof Date) {
    strictDatePair(foo) // error TS2345: Argument of type '[Date | undefined, Date | undefined]' is not assignable to parameter of type '[Date, Date]'.
}

Expected behavior:

If item is narrowed to a specific type it should be reflected in array

Actual behavior:

It's only related to individual item

Playground Link: https://www.typescriptlang.org/play/index.html#code/MYewdgzgLgBAZiEAuGBtAIgQygUxgHxgFcwATHOASzB1IBoYtcDiyLraBdGAXjRPJUa9GDQDujbDgAUASk4AoBaEixoAJ0rAoTHAAVMldbxjTSUiCgxSGuzrN4A+GCoggANjgB07kAHMzC1klSjhpBBBUAAZuamhMMGAcEDhJZgAydPhEVABGWNUEpJS0nAcAbwUYapgNLR0pAyNpVAjozgY2-PsFAF8QsLaYmDioIuTU3RhM7Mj8kcLEidKKqpq67V0m9XDEYN6gA

Related Issues: No

[nmain]

This is a duplicate of #31755, even though the tuple type makes it look a bit different.