Fixes #19223.
Change-Id: I4cc8e81559a1313e1477ee36902e1b653155a888
Reviewed-on: https://go-review.googlesource.com/37374
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
<p>
Sometimes you need to distinguish a missing entry from
a zero value. Is there an entry for <code>"UTC"</code>
-or is that the empty string because it's not in the map at all?
+or is that 0 because it's not in the map at all?
You can discriminate with a form of multiple assignment.
</p>
<pre>