| UCAR | Distribution.SPDX.LicenseId, Distribution.SPDX |
| UCL_1_0 | Distribution.SPDX.LicenseId, Distribution.SPDX |
| UHC | Distribution.Compiler |
| unAbiHash | Distribution.Types.AbiHash, Distribution.Package |
| UnboxedSums | Language.Haskell.Extension |
| UnboxedTuples | Language.Haskell.Extension |
| unComponentId | Distribution.Types.ComponentId, Distribution.Package |
| uncurry | Distribution.Compat.Prelude |
| UndecidableInstances | Language.Haskell.Extension |
| UndecidableSuperClasses | Language.Haskell.Extension |
| undefined | Distribution.Compat.Prelude |
| unDefUnitId | Distribution.Types.UnitId, Distribution.Backpack, Distribution.Package |
| unexpected | Distribution.Compat.Parsing, Distribution.Compat.CharParsing |
| unFlagAssignment | Distribution.Types.Flag, Distribution.PackageDescription |
| unFlagName | Distribution.Types.Flag, Distribution.PackageDescription |
| unfoldr | Distribution.Compat.Prelude |
| unfoldrM | Distribution.Utils.Generic |
| UnicodeSyntax | Language.Haskell.Extension |
| Unicode_DFS_2015 | Distribution.SPDX.LicenseId, Distribution.SPDX |
| Unicode_DFS_2016 | Distribution.SPDX.LicenseId, Distribution.SPDX |
| Unicode_TOU | Distribution.SPDX.LicenseId, Distribution.SPDX |
| unintersperse | Distribution.Utils.Generic |
| unionLeft | Distribution.Compat.Graph |
| unionRight | Distribution.Compat.Graph |
| unionVersionIntervals | Distribution.Types.VersionInterval.Legacy |
| UnionVersionRanges | Distribution.Types.VersionRange.Internal |
| unionVersionRanges | Distribution.Types.VersionRange.Internal, Distribution.Types.VersionRange, Distribution.Version |
| UnionVersionRangesF | Distribution.Types.VersionRange.Internal, Distribution.Types.VersionRange, Distribution.Version |
| uniqueField | Distribution.FieldGrammar.Class, Distribution.FieldGrammar |
| uniqueFieldAla | Distribution.FieldGrammar.Class, Distribution.FieldGrammar |
| UnitId | Distribution.Types.UnitId, Distribution.Package |
| Universal_FOSS_exception_1_0 | Distribution.SPDX.LicenseExceptionId, Distribution.SPDX |
| unknownCompilerInfo | Distribution.Compiler |
| UnknownExtension | Language.Haskell.Extension |
| UnknownLanguage | Language.Haskell.Extension |
| UnknownLicense | Distribution.License |
| unless | Distribution.Compat.Prelude |
| unLex | Distribution.Fields.LexerMonad |
| Unlicense | Distribution.SPDX.LicenseId, Distribution.SPDX |
| UnliftedDatatypes | Language.Haskell.Extension |
| UnliftedFFITypes | Language.Haskell.Extension |
| UnliftedNewtypes | Language.Haskell.Extension |
| unlines | Distribution.Compat.Prelude |
| unpack | Distribution.Compat.Newtype |
| unpack' | Distribution.Compat.Newtype |
| unPackageName | Distribution.Types.PackageName, Distribution.Package, Distribution.PackageDescription |
| unPackageNameST | Distribution.Types.PackageName, Distribution.Package, Distribution.PackageDescription |
| unPkgconfigName | Distribution.Types.PkgconfigName, Distribution.Package, Distribution.PackageDescription |
| unPP | Distribution.Parsec |
| UnqualComponentName | Distribution.Types.UnqualComponentName, Distribution.PackageDescription |
| unqualComponentNameToPackageName | Distribution.Types.UnqualComponentName, Distribution.PackageDescription |
| Unsafe | Language.Haskell.Extension |
| unsafeFromUTF8BS | Distribution.Utils.ShortText |
| unsafeMakeSymbolicPath | Distribution.Utils.Path |
| unsafeMkDefUnitId | Distribution.Types.UnitId, Distribution.Package |
| unsnoc | Distribution.Utils.Generic |
| unsnocNE | Distribution.Utils.Generic |
| UnspecifiedLicense | Distribution.License |
| until | Distribution.Compat.Prelude |
| unUnitId | Distribution.Types.UnitId, Distribution.Package |
| unUnqualComponentName | Distribution.Types.UnqualComponentName, Distribution.PackageDescription |
| unUnqualComponentNameST | Distribution.Types.UnqualComponentName, Distribution.PackageDescription |
| unvalidateBenchmark | Distribution.PackageDescription.FieldGrammar |
| unvalidateTestSuite | Distribution.PackageDescription.FieldGrammar |
| unVersionIntervals | Distribution.Types.VersionInterval, Distribution.Version |
| unwords | Distribution.Compat.Prelude |
| unzip | Distribution.Compat.Prelude |
| unzip3 | Distribution.Compat.Prelude |
| updatePackageDescription | Distribution.Types.PackageDescription, Distribution.PackageDescription |
| UPL_1_0 | Distribution.SPDX.LicenseId, Distribution.SPDX |
| upper | Distribution.Compat.CharParsing |
| UpperBound | |
| 1 (Type/Class) | Distribution.Types.VersionInterval.Legacy |
| 2 (Data Constructor) | Distribution.Types.VersionInterval.Legacy |
| 3 (Type/Class) | Distribution.Types.VersionInterval, Distribution.Version |
| 4 (Data Constructor) | Distribution.Types.VersionInterval, Distribution.Version |
| use | Distribution.Compat.Lens |
| usedExtensions | Distribution.Types.BuildInfo, Distribution.PackageDescription |
| userBug | Distribution.PackageDescription.Utils |
| userError | Distribution.Compat.Prelude |
| usesTemplateHaskellOrQQ | Distribution.Types.BuildInfo, Distribution.PackageDescription |
| U_boot_exception_2_0 | Distribution.SPDX.LicenseExceptionId, Distribution.SPDX |