type I interface { m() }

func f(y I) {
	s := y.(string)        // illegal: string does not implement I (missing method m)
	r := y.(io.Reader)     // r has type io.Reader and the dynamic type of y must implement both I and io.Reader
	…
}
</pre>

<p>
A type assertion used in an <a href="#Assignments">assignment</a> or initialization of the special form
</p>

<pre>

type I interface { m() }

func f(y I) {
	s := y.(string)        // illegal: string does not implement I (missing method m)
	r := y.(io.Reader)     // r has type io.Reader and the dynamic type of y must implement both I and io.Reader
	…
}
</pre>

<p>
A type assertion used in an <a href="#Assignment_statements">assignment statement</a> or initialization of the special form
</p>

    </p>
  </dd>
</dl><!-- html/template -->

<dl id="io"><dt><a href="/pkg/io/">io</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/61870, CL 526855 -->
      The new <a href="/pkg/io#SectionReader.Outer"><code>SectionReader.Outer</code></a> method returns the <a href="/pkg/io#ReaderAt"><code>ReaderAt</code></a>, offset, and size passed to <a href="/pkg/io#NewSectionReader"><code>NewSectionReader</code></a>.
    </p>
  </dd>

The document is not comprehensive.
</p>

<p>
The assembler is based on the input style of the Plan 9 assemblers, which is documented in detail
<a href="https://9p.io/sys/doc/asm.html">elsewhere</a>.
If you plan to write assembly language, you should read that document although much of it is Plan 9-specific.
The current document provides a summary of the syntax and the differences with