Empty case without `{}`

GHC accepts this file, using `EmptyCase` with “implicit” braces for:
```
{-# LANGUAGE EmptyCase #-}

foo b = case b of
```

With haskell-src-exts, I get
```
ghci> Language.Haskell.Exts.parseFile "/tmp/Test.hs"
ParseFailed (SrcLoc "/tmp/Test.hs" 4 12) "Parse error: ;"
```

It works if I write
```
{-# LANGUAGE EmptyCase #-}

foo b = case b of {}
```