elude-val">Err</span>(<span class="ident">e</span>),
        <span class="prelude-val">Ok</span>((<span class="ident">i1</span>,<span class="ident">o</span>))    <span class="op">=&gt;</span> {
          <span class="kw">match</span> <span class="ident">space</span>(<span class="ident">i1</span>) {
            <span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=&gt;</span> <span class="prelude-val">Err</span>(<span class="prelude-val">Err</span>::<span class="ident">convert<