/a>-like usage - emit the error but do not abort the macro.
The compilation will fail nonetheless. Expands to <a href="https://doc.rust-lang.org/std/primitive.unit.html"><code>()</code></a> (unit type).</p>
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<p><a href="macro.emit_call_site_warning.html"><code>emit_call_site_error!</code></a>:</p>
<p>Shortcut for <code>emit_error!(Span::call_site(), ...)</code>. Expands to <a href="https://doc.rust-lang.org/std/primitive.unit.html"><code>()</code></a> (unit type).</p>
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<p><a href="macro.