<i>W</i>(<i>r</i>) must be a write <i>w</i> that is <i>visible</i> to <i>r</i>,
where visible means that both of the following hold:
</p>

<ol>
	<li><i>w</i> happens before <i>r</i>.</li>
	<li><i>w</i> does not happen before any other write <i>w'</i> (to <i>x</i>) that happens before <i>r</i>.</li>
</ol>

<p>
A <i>read-write data race</i> on memory location <i>x</i>
consists of a read-like memory operation <i>r</i> on <i>x</i>

s3 := append(s2, s0...)            // append a slice              s3 == []int{0, 0, 2, 3, 5, 7, 0, 0}
s4 := append(s3[3:6], s3[2:]...)   // append overlapping slice    s4 == []int{3, 5, 7, 2, 3, 5, 7, 0, 0}

var t []interface{}
t = append(t, 42, 3.1415, "foo")   //                             t == []interface{}{42, 3.1415, "foo"}

var b []byte
b = append(b, "bar"...)            // append string contents      b == []byte{'b', 'a', 'r' }

s3 := append(s2, s0...)            // append a slice              s3 is []int{0, 0, 2, 3, 5, 7, 0, 0}
s4 := append(s3[3:6], s3[2:]...)   // append overlapping slice    s4 is []int{3, 5, 7, 2, 3, 5, 7, 0, 0}

var t []interface{}
t = append(t, 42, 3.1415, "foo")   //                             t is []interface{}{42, 3.1415, "foo"}

var b []byte