| unFix | Top.Monad.StateFix |
| unfreezeVariablesInType | Top.Types.Primitive, Top.Types |
| unGS | Top.Implementation.FastSubstitution |
| unifiable | Top.Types.Unification, Top.Types |
| unifiableList | Top.Types.Unification, Top.Types |
| UnificationError | Top.Types.Unification, Top.Types |
| unificationErrorLabel | Top.Interface.Substitution |
| unifyTerms | Top.Interface.Substitution |
| uniqueCounter | Top.Solver |
| uniqueFromResult | Top.Solver |
| unitTree | Top.Ordering.Tree |
| Universal | Top.Types.Quantification, Top.Types |
| unless | Top.Monad.StateFix, Top.Monad.Select, Top.Solver |
| unmarkPossibleErrors | |
| 1 (Function) | Top.Implementation.TypeGraph.Class |
| 2 (Function) | Top.Implementation.TypeGraph.ClassMonadic |
| unqualify | Top.Types.Qualification, Top.Types |
| unquantify | Top.Types.Quantification, Top.Types |
| unresolvedLabel | Top.Implementation.Overloading |
| unresolvedPredicate | Top.Constraint.Information |
| unreveal | Top.Types.Quantification, Top.Types |
| unskolemize | Top.Types.Quantification, Top.Types |
| unSS | Top.Implementation.SimpleSubstitution |
| Up | Top.Ordering.Tree |
| updateErrorInfo | Top.Interface.Basic |
| updateGroupOf | Top.Implementation.TypeGraph.Standard |
| useOption | Top.Util.Option |
| useTheNameMap | Top.Types.Quantification, Top.Types |
| useTypeGraph | Top.Implementation.TypeGraph.ClassMonadic |