9

**Bug introduced in 7.0 and fixed in 10.0.0**

Maybe this is a bug or maybe Infix acts differently than the other functions.

The fact is that both:

```
TreeForm[Infix[f[x, a]]]
```

and

```
ToString[Infix[f[x, a]]]
```

crash the kernel. I use Mathematica 9.0 and maybe there are other cases that Infix behaves strangely.

Does anybody can explain why this happens ?

1confirmed (9.000). – george2079 – 2013-12-04T19:08:20.797

I confirm this behavior for

Mathematica8.0.4 under Windows 7 x64. – Alexey Popkov – 2013-12-05T07:06:01.037