| unArr | Feldspar.Representation |
| Uncloseable | Feldspar.Run.Concurrent |
| unComp | Feldspar.Representation |
| uncurry | Feldspar, Feldspar.Run |
| unData | Feldspar.Representation |
| undefined | Feldspar, Feldspar.Run |
| unIArr | Feldspar.Representation |
| union | Data.Selection |
| universal | Data.Selection |
| unless | Feldspar, Feldspar.Run |
| unnest | Feldspar.Data.Array, Feldspar.Data.Vector |
| unPrim | Feldspar.Primitive.Representation |
| unRef | Feldspar.Representation |
| unRun | Feldspar.Run.Representation |
| Unsafe | Feldspar.Representation |
| unsafeBalancedDiv | Feldspar.Frontend, Feldspar, Feldspar.Run |
| unsafeEqArrIArr | Feldspar.Representation |
| unsafeFreezeArr | Feldspar.Frontend, Feldspar, Feldspar.Run |
| unsafeFreezeRef | Feldspar.Frontend, Feldspar, Feldspar.Run |
| unsafeFreezeRefV | Feldspar.Run.Compile |
| unsafeFreezeSlice | Feldspar.Frontend, Feldspar, Feldspar.Run |
| unsafeFreezeStore | |
| 1 (Function) | Feldspar.Data.Storable |
| 2 (Function) | Feldspar.Data.Buffered |
| unsafeFreezeStore2 | Feldspar.Data.Buffered |
| unsafeFreezeStoreRep | Feldspar.Data.Storable |
| UnsafePerform | Feldspar.Representation |
| unsafePerform | Feldspar.Frontend, Feldspar, Feldspar.Run |
| unsafeSwap | Feldspar.Run.Frontend, Feldspar.Run |
| unsafeSwapArr | Feldspar.Run.Frontend, Feldspar.Run |
| unsafeThawArr | Feldspar.Frontend, Feldspar, Feldspar.Run |
| unsafeTransSmallExp | Feldspar.Run.Compile |
| unStore | Feldspar.Data.Storable |
| untypedReadChan | Feldspar.Run.Concurrent |
| untypedReadChanBuf | Feldspar.Run.Concurrent |
| untypedWriteChan | Feldspar.Run.Concurrent |
| untypedWriteChanBuf | Feldspar.Run.Concurrent |
| unviewPrimTypeRep | Feldspar.Primitive.Representation |
| UserAssertion | Feldspar.Representation, Feldspar, Feldspar.Run |