Index - U
| Uncommitted | Hydra.Model |
| UnexpectedParty | Hydra.Model |
| UnknownAddress | Hydra.Model |
| unsafeConstructorName | Hydra.Model |
| unwrapAddress | Hydra.ModelSpec |
| UseInputFromOtherHead | Hydra.Chain.Direct.Contract.Abort |
| UsePTFromDifferentHead | Hydra.Chain.Direct.Contract.Commit |