<p dir="auto">This is a tracking issue for the unstable <code class="notranslate">iter_to_slice</code> feature in the standard library. The <code class="notranslate">into_vec</code> adaptor for <code class="notranslate">vec::IntoIter</code> was recently removed, and these may also want to be removed. It's somewhat unclear how useful it is to have iterators enhanced with this kind of functionality.</p>
<p dir="auto">I've hit this while working on <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="23588132" data-permission-text="Title is private" data-url="https://github.com/rust-lang/rust/issues/10769" data-hovercard-type="pull_request" data-hovercard-url="/rust-lang/rust/pull/10769/hovercard" href="https://github.com/rust-lang/rust/pull/10769">#10769</a>, where I would need to change <code class="notranslate">ast::ty_nil</code> (and all the code using it) for consistency's sake and a great total of one usecase, a noop <code class="notranslate">..()</code>.</p>
<p dir="auto">The only problem I see with <code class="notranslate">ty_tup(~[])</code> is the possibility of heap allocation.<br>
If that's a reason for concern, this can wait for the proposed changes to vectors, where <code class="notranslate">~[]</code> would be represented as <code class="notranslate">(0u, 0u)</code>.</p>