\section{s:empty-variants}{Empty variant types}
%HEVEA\cutname{emptyvariants.html}
(Introduced in 4.07.0)

\begin{syntax}
type-representation:
          ...
        | '=' '|'
\end{syntax}
This extension allows user to define empty variants.
Empty variant type can be eliminated by refutation case of pattern matching.
\begin{caml_example*}{verbatim}
type t = |
let f (x: t) = match x with _ -> .
\end{caml_example*}