spec: clarify that f(g()) requires that g return >= 1 value
Fixes #4573.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7322043
diff --git a/doc/go_spec.html b/doc/go_spec.html
index b8502bd..30c9a97 100644
--- a/doc/go_spec.html
+++ b/doc/go_spec.html
@@ -1,6 +1,6 @@
<!--{
"Title": "The Go Programming Language Specification",
- "Subtitle": "Version of January 21, 2013",
+ "Subtitle": "Version of February 9, 2013",
"Path": "/ref/spec"
}-->
@@ -2765,13 +2765,14 @@
</p>
<p>
-As a special case, if the return parameters of a function or method
+As a special case, if the return values of a function or method
<code>g</code> are equal in number and individually
assignable to the parameters of another function or method
<code>f</code>, then the call <code>f(g(<i>parameters_of_g</i>))</code>
will invoke <code>f</code> after binding the return values of
<code>g</code> to the parameters of <code>f</code> in order. The call
-of <code>f</code> must contain no parameters other than the call of <code>g</code>.
+of <code>f</code> must contain no parameters other than the call of <code>g</code>,
+and <code>g</code> must have at least one return value.
If <code>f</code> has a final <code>...</code> parameter, it is
assigned the return values of <code>g</code> that remain after
assignment of regular parameters.
