Index - O
| onCompilationError | Hint.Internal | 
| Option | Language.Haskell.Interpreter | 
| OptionVal | Language.Haskell.Interpreter | 
| OverlappingInstances | Language.Haskell.Interpreter, Language.Haskell.Interpreter.Extension | 
| OverloadedLabels | Language.Haskell.Interpreter, Language.Haskell.Interpreter.Extension | 
| OverloadedLists | Language.Haskell.Interpreter, Language.Haskell.Interpreter.Extension | 
| OverloadedStrings | Language.Haskell.Interpreter, Language.Haskell.Interpreter.Extension |