TypeScript Version: 3.2.4

Search Terms:
Tuple, merge, combine

Code

function combine<T, U extends any[]>(item: T, items: U): [T, ...U] {
    return [] as any;
}
const result = combine("hello", ["goodbye", 123, true]);

Expected behavior:
result should be typed as [string, string, number, boolean].

Actual behavior:
Compile error:
A rest element type must be an array type.

Playground Link:
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Related Issues: