 `/STARTRUNE/` `/ENDRUNE/`}}
-->    delta := &#39;δ&#39; <span class="comment">// delta has type rune.</span>
    var DELTA rune
    DELTA = unicode.ToUpper(delta)
    epsilon := unicode.ToLower(DELTA + 1)
    if epsilon != &#39;δ&#39;+1 {
        log.Fatal(&#34;inconsistent casing for Greek&#34;)
    }</pre>

<p>
<em>Updating</em>:
Most source code will be unaffected by this because the type inference from
<code>:=</code> initializers introduces the new type silently, and it propagates
from there.
Some c