export fn entry() void {
    var arr: [4]f32 = undefined;
    arr = concat();
}
fn concat() [16]f32 {
    return @splat(0.0);
}

// error
//
// :3:17: error: expected type '[4]f32', found '[16]f32'
// :3:17: note: destination has length 4
// :3:17: note: source has length 16
