| objectName | GHC.ExecutionStack.Internal,GHC.ExecutionStack |
| odd | Prelude |
| oldGenFactor | GHC.RTS.Flags |
| on | Data.Function |
| OneLineGCStats | GHC.RTS.Flags |
| OneShot | GHC.Event |
| oneShot | GHC.Exts |
| onException | Control.Exception.Base,Control.Exception |
| Op | |
| 1 (Type/Class) | Data.Functor.Contravariant |
| 2 (Data Constructor) | Data.Functor.Contravariant |
| openBinaryFile | GHC.IO.Handle.FD,System.IO |
| openBinaryTempFile | System.IO |
| openBinaryTempFileWithDefaultPermissions | System.IO |
| openFile | GHC.IO.Handle.FD,System.IO |
| openFileBlocking | GHC.IO.Handle.FD |
| OpenPunctuation | Data.Char |
| openTempFile | System.IO |
| openTempFileWithDefaultPermissions | System.IO |
| OptArg | System.Console.GetOpt |
| OptDescr | System.Console.GetOpt |
| Option | |
| 1 (Data Constructor) | System.Console.GetOpt |
| 2 (Type/Class) | Data.Semigroup |
| 3 (Data Constructor) | Data.Semigroup |
| option | |
| 1 (Function) | Text.ParserCombinators.ReadP |
| 2 (Function) | Data.Semigroup |
| optional | |
| 1 (Function) | Text.ParserCombinators.ReadP |
| 2 (Function) | Control.Applicative |
| or | |
| 1 (Function) | GHC.List,GHC.OldList |
| 2 (Function) | Data.Foldable,Data.List,Prelude |
| or# | GHC.Exts |
| Ord | Data.Ord,Prelude |
| ord | Data.Char |
| ord# | GHC.Exts |
| Ord1 | Data.Functor.Classes |
| Ord2 | Data.Functor.Classes |
| Ordering | Data.Ord,Prelude |
| orElse | GHC.Conc.Sync,GHC.Conc |
| orI# | GHC.Exts |
| orNatural | GHC.Natural |
| os | System.Info |
| OtherLetter | Data.Char |
| OtherNumber | Data.Char |
| OtherPunctuation | Data.Char |
| OtherSymbol | Data.Char |
| otherwise | Data.Bool,Prelude |
| outer | Data.Type.Equality |
| outputNL | GHC.IO.Handle,System.IO |
| OutputUnderflow | GHC.IO.Encoding.Types,GHC.IO.Encoding |
| Overflow | Control.Exception.Base,Control.Exception |