code review 5369090: spec: disallow general func, map comparisons

doc/go_spec.html

 <!-- title The Go Programming Language Specification -->
-<!-- subtitle Version of November 9, 2011 -->
+<!-- subtitle Version of November 13, 2011 -->
 
 <!--
 TODO
 [ ] need language about function/method calls and parameter passing rules
 [ ] last paragraph of #Assignments (constant promotion) should be elsewhere
     and mention assignment to empty interface.
 [ ] need to say something about "scope" of selectors?
 [ ] clarify what a field name is in struct declarations
     (struct{T} vs struct {T T} vs struct {t T})
 [ ] need explicit language about the result type of operations
@@ skipping 2946 matching lines @@
         </li>
         <li>
         Boolean values are equal if they are either both
         <code>true</code> or both <code>false</code>.
         </li>
         <li>
         Pointer values are equal if they point to the same location
         or if both are <code>nil</code>.
         </li>
         <li>
-        Function values are equal if they refer to the same function
-        or if both are <code>nil</code>.
+        A slice, map, or function value may be compared only to <code>nil</code>.
         </li>
         <li>
-        A slice value may only be compared to <code>nil</code>.
-        </li>
-        <li>
-        Channel and map values are equal if they were created by the same call to <code>make</code>
+        Channel values are equal if they were created by the same call to <code>make</code>
         (§<a href="#Making_slices_maps_and_channels">Making slices, maps, and channels</a>)
         or if both are <code>nil</code>.
         </li>
         <li>
         Interface values are equal if they have <a href="#Type_identity">identical</a> dynamic types and
         equal dynamic values or if both are <code>nil</code>.
         </li>
         <li>
         An interface value <code>x</code> is equal to a non-interface value
         <code>y</code> if the dynamic type of <code>x</code> is identical to
@@ skipping 2340 matching lines @@
    <code>unsafe.Alignof(x[0])</code>, but at least 1.
 </li>
 </ol>
 
 <span class="alert">
 <h2 id="Implementation_differences">Implementation differences - TODO</h2>
 <ul>
         <li><code>len(a)</code> is only a constant if <code>a</code> is a (qualified) identifier denoting an array or pointer to an array.</li>
 </ul>
 </span>