This doco said that use of => as an operator "is deprecated".
It's been fully disallowed since
865f14a2d back in 9.5, but
evidently that commit missed updating this statement.
Do so now.
There are a few restrictions on your choice of name:
<itemizedlist>
<listitem>
- <para><literal>--</literal> and <literal>/*</literal> cannot appear anywhere in an operator name,
+ <para>
+ <literal>--</literal> and <literal>/*</literal> cannot appear anywhere in an operator name,
since they will be taken as the start of a comment.
</para>
</listitem>
</listitem>
<listitem>
<para>
- The use of <literal>=></literal> as an operator name is deprecated. It may
- be disallowed altogether in a future release.
+ The symbol <literal>=></literal> is reserved by the SQL grammar,
+ so it cannot be used as an operator name.
</para>
</listitem>
</itemizedlist>