| UInfixE | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| uInfixE | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| UInfixP | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| uInfixP | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| UInfixT | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| uInfixT | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| UnboundVarE | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unboundVarE | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| unboxedSumBars | Language.Haskell.TH.Ppr | 
| unboxedSumDataName | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnboxedSumE | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unboxedSumE | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| UnboxedSumP | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unboxedSumP | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| UnboxedSums | Language.Haskell.TH.LanguageExtensions, Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnboxedSumT | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unboxedSumT | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| unboxedSumTypeName | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnboxedTupE | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unboxedTupE |  | 
| 1 (Function) | Language.Haskell.TH.Lib.Internal | 
| 2 (Function) | Language.Haskell.TH.Lib, Language.Haskell.TH | 
| unboxedTupleDataName | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnboxedTuples | Language.Haskell.TH.LanguageExtensions, Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnboxedTupleT | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unboxedTupleT | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| unboxedTupleTypeName | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnboxedTupP | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unboxedTupP | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| UndecidableInstances | Language.Haskell.TH.LanguageExtensions, Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UndecidableSuperClasses | Language.Haskell.TH.LanguageExtensions, Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnicodeSyntax | Language.Haskell.TH.LanguageExtensions, Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| Unidir | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unidir | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| Uniq | Language.Haskell.TH.Syntax | 
| Unlifted | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnliftedFFITypes | Language.Haskell.TH.LanguageExtensions, Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| UnliftedNewtypes | Language.Haskell.TH.LanguageExtensions, Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unopPrec | Language.Haskell.TH.Ppr | 
| unpacked | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| unQ | Language.Haskell.TH.Syntax | 
| Unsafe | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unsafe | Language.Haskell.TH.Lib.Internal, Language.Haskell.TH.Lib, Language.Haskell.TH | 
| unsafeCodeCoerce | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unsafeTExpCoerce | Language.Haskell.TH.Syntax | 
| unType | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unTypeCode | Language.Haskell.TH.Syntax, Language.Haskell.TH | 
| unTypeQ | Language.Haskell.TH.Syntax |