teral notranslate"><span class="pre">instantiation_error</span></code></div>
</div>
<div class="line">Goal is neither a variable nor a callable term:</div>
<div class="line-block">
<div class="line"><code class="docutils literal notranslate"><span class="pre">type_error(callable,</span> <span class="pre">Goal)</span></code></div>
</div>
<div class="line">Tag is not a variable:</div>
<div class="line-block">
<div class="line"><code class="docutils literal notranslate"><span class="pre">uninstantiation_error(