Some comments are removed

**TypeScript Version:** 

1.7.5

**Code**

```
export function lex(source: string): Array<string>
{//validation and tokenization
}
```

``` ts
// A self-contained demonstration of the problem follows...

The comment after the beginning curly brace is discarded.

```

**Expected behavior:**

After being compiled the comment is not discarded.

**Actual behavior:** 
The comment _is_ discarded.
