#data
<a xmlns="http://www.w3.org/1999/xhtml">
  <a href="">b</a>
</a>
#errors
/a/a;element not allowed:minus;m

#data
<a xmlns="http://www.w3.org/1999/xhtml">
  <a>b</a>
  <a href="">b</a>
</a>
#errors
/a/a;element not allowed:minus;m
/a/a;element not allowed:minus;m

#data
<a xmlns="http://www.w3.org/1999/xhtml">
  <em><a href="">b</a></em>
</a>
#errors
/a/em/a;element not allowed:minus;m

#data
<a xmlns="http://www.w3.org/1999/xhtml">
  <a>b</a>
</a>
#errors
/a/a;element not allowed:minus;m

#data
<a href="" xmlns="http://www.w3.org/1999/xhtml">
  <a>b</a>
</a>
#errors
/a/a;element not allowed:minus;m

#data
<a xmlns="http://www.w3.org/1999/xhtml">
  <em><a>b</a></em>
</a>
#errors
/a/em/a;element not allowed:minus;m

#data
<button xmlns="http://www.w3.org/1999/xhtml">
  <a>b</a>
</button>
#errors

#data
<button xmlns="http://www.w3.org/1999/xhtml">
  <a href="">b</a>
</button>
#errors
/button/a;element not allowed:minus;m

#data
<button xmlns="http://www.w3.org/1999/xhtml">
  <a tabindex="0">b</a>
</button>
#errors
/button/a;element not allowed:minus;m

#data
<canvas xmlns="http://www.w3.org/1999/xhtml">
  <a>b</a>
</canvas>
#errors

#data
<canvas xmlns="http://www.w3.org/1999/xhtml">
  <a href="">b</a>
</canvas>
#errors

#data
<video src="x" xmlns="http://www.w3.org/1999/xhtml">
  <a>b</a>
</video>
#errors

#data
<video src="x" xmlns="http://www.w3.org/1999/xhtml">
  <a href="">b</a>
</video>
#errors