anonymous given parse error

## minimized code

```Scala
trait Foo
trait Bar

given as Foo 
given as Bar
//    ^
//    not found: type as

trait C
trait Baz[A]

given as C
given [A] as Baz[A]
//    ^
//    an identifier expected, but '[' found
```

## expectation

These should parse and are fixed by adding brackets to the above given, e.g. `given as Foo {}` or a newline in between.