wrong return-value count for tuple return type

Why this fires¶

A function declares a tuple return type (-> (T1, T2, ...)), but one of its return statements returns a different number of values than the tuple has slots.

fn min_max(xs: [int]) -> (int, int) {
    return xs[0]
    //     ^^^^^ error[TE006]: function 'min_max' returns 1 value(s) but 2 are expected
    //           (return type is a 2-tuple)
}

Fix it¶

Return exactly as many values as the declared tuple has slots:

fn min_max(xs: [int]) -> (int, int) {
    return xs[0], xs[1]     // ok — 2 values for a 2-tuple
}

A single array literal is also accepted as a stand-in for the whole tuple, since it destructures the same way at the call site:

fn min_max(xs: [int]) -> (int, int) {
    return [xs[0], xs[1]]   // ok
}

See also¶

• TE007 — the opposite mismatch: returning multiple values from a function declared with a single (non-tuple) return type.
• /docs/functions — multi-return functions.