| O | GHC.Internal.Base |
| objectName | GHC.Internal.ExecutionStack.Internal, GHC.Internal.ExecutionStack |
| odd | GHC.Internal.Real |
| oldGenFactor | GHC.Internal.RTS.Flags |
| on | GHC.Internal.Data.Function |
| One | GHC.Internal.Base, GHC.Internal.Exts |
| oneBits | GHC.Internal.Data.Bits |
| OneLineGCStats | GHC.Internal.RTS.Flags |
| OneShot | GHC.Internal.Event |
| oneShot | GHC.Internal.Base, GHC.Internal.Exts |
| onException | |
| 1 (Function) | GHC.Internal.IO |
| 2 (Function) | GHC.Internal.Control.Exception.Base, GHC.Internal.Control.Exception |
| Opaque | GHC.Internal.Base |
| openBinaryFile | |
| 1 (Function) | GHC.Internal.IO.Handle.FD |
| 2 (Function) | GHC.Internal.IO.StdHandles, GHC.Internal.System.IO |
| openBinaryTempFile | GHC.Internal.System.IO |
| openBinaryTempFileWithDefaultPermissions | GHC.Internal.System.IO |
| openFile | |
| 1 (Function) | GHC.Internal.IO.FD |
| 2 (Function) | GHC.Internal.IO.Handle.FD |
| 3 (Function) | GHC.Internal.IO.StdHandles, GHC.Internal.System.IO |
| openFileBlocking | |
| 1 (Function) | GHC.Internal.IO.Handle.FD |
| 2 (Function) | GHC.Internal.IO.StdHandles |
| openFileWith | GHC.Internal.IO.FD |
| OpenPunctuation | GHC.Internal.Unicode |
| openTempFile | GHC.Internal.System.IO |
| openTempFileWithDefaultPermissions | GHC.Internal.System.IO |
| openTextEncoding | GHC.Internal.IO.Handle.Internals |
| option | GHC.Internal.Text.ParserCombinators.ReadP |
| optional | GHC.Internal.Text.ParserCombinators.ReadP |
| or | |
| 1 (Function) | GHC.Internal.List, GHC.Internal.Data.OldList |
| 2 (Function) | GHC.Internal.Data.Foldable, GHC.Internal.Data.List |
| or# | GHC.Internal.Base, GHC.Internal.Exts |
| or64# | GHC.Internal.Base, GHC.Internal.Exts |
| Ord | GHC.Internal.Base, GHC.Internal.Data.Ord |
| ord | GHC.Internal.Base |
| ord# | GHC.Internal.Base, GHC.Internal.Exts |
| OrdCond | GHC.Internal.Data.Type.Ord |
| Ordering | GHC.Internal.Base, GHC.Internal.Data.Ord, GHC.Internal.Exts |
| OrderingI | GHC.Internal.Data.Type.Ord, GHC.Internal.TypeLits |
| orElse | GHC.Internal.Conc.Sync |
| orI# | GHC.Internal.Base, GHC.Internal.Exts |
| orInteger | GHC.Internal.Integer |
| orNatural | GHC.Internal.Natural |
| orWord16# | GHC.Internal.Base, GHC.Internal.Exts |
| orWord32# | GHC.Internal.Base, GHC.Internal.Exts |
| orWord8# | GHC.Internal.Base, GHC.Internal.Exts |
| OtherError | GHC.Internal.IO.Exception |
| OtherLetter | GHC.Internal.Unicode |
| OtherNumber | GHC.Internal.Unicode |
| OtherPunctuation | GHC.Internal.Unicode |
| OtherSymbol | GHC.Internal.Unicode |
| otherwise | GHC.Internal.Base, GHC.Internal.Data.Bool |
| outer | GHC.Internal.Data.Type.Equality |
| outputNL | GHC.Internal.IO.Handle.Types, GHC.Internal.IO.Handle, GHC.Internal.System.IO |
| OutputUnderflow | GHC.Internal.IO.Encoding.Types, GHC.Internal.IO.Encoding |
| Overflow | GHC.Internal.Exception.Type, GHC.Internal.Exception, GHC.Internal.Control.Exception.Base, GHC.Internal.Control.Exception |
| overflowError | GHC.Internal.Real |
| overflowException | GHC.Internal.Exception.Type, GHC.Internal.Exception |
| o_APPEND | GHC.Internal.System.Posix.Internals |
| o_BINARY | GHC.Internal.System.Posix.Internals |
| o_CREAT | GHC.Internal.System.Posix.Internals |
| o_EXCL | GHC.Internal.System.Posix.Internals |
| o_NOCTTY | GHC.Internal.System.Posix.Internals |
| o_NONBLOCK | GHC.Internal.System.Posix.Internals |
| o_RDONLY | GHC.Internal.System.Posix.Internals |
| o_RDWR | GHC.Internal.System.Posix.Internals |
| o_TRUNC | GHC.Internal.System.Posix.Internals |
| o_WRONLY | GHC.Internal.System.Posix.Internals |