Re: [PATCH] Extend ALTER OPERATOR to support adding commutator, negator, hashes, and merges

in doc/src/sgml/ref/alter_operator.sgml

   <varlistentry>
    <term><literal>HASHES</literal></term>
    <listitem>
     <para>
     Indicates this operator can support a hash join. Can only be set
when the operator does not support a hash join.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>MERGES</literal></term>
    <listitem>
     <para>
     Indicates this operator can support a merge join. Can only be set
when the operator does not support a merge join.
     </para>
    </listitem>
   </varlistentry>
------------------------
if the operator cannot support hash/merge join, it can't do ALTER
OPERATOR oprname(left_arg, right_arg) SET (HASHES/MERGES = false);

I think it means:
Can only be set when the operator does support a hash/merge join. Once
set to true, it cannot be reset to false.