anchor.diff:      try
         // Some preliminary checks 
         mutRecDefns |> MutRecShapes.iterTycons (fun tyconData ->
  -             let (MutRecDefnsPhase2DataForTycon(_, declKind, tcref, _, _, _, members, m, newslotsOK)) = tyconData
  +             let (MutRecDefnsPhase2DataForTycon(_, _, declKind, tcref, _, _, _, members, m, newslotsOK)) = tyconData
                let tcaug = tcref.TypeContents
                if tcaug.tcaug_closed && declKind <> ExtrinsicExtensionBinding then 
                  error(InternalError("Intrinsic augmentations of types are only permitted in the same file as the definition of the type",m))
  
positive.code:             
              let repr = SynTypeDefnSimpleRepr.General(kind,inherits,slotsigs,fields,isConcrete,false,None,m)
              let isAtOriginalTyconDefn = true
              let tyconCore = MutRecDefnsPhase1DataForTycon (synTyconInfo, repr,implements2@implements1,preEstablishedHasDefaultCtor,hasSelfReferentialCtor,isAtOriginalTyconDefn)
  
              tyconCore, (synTyconInfo,members@extraMembers)
  
  
negative.code:         //    uncheckedBindsRev:   accumulation of unchecked bindings
          let (defnsAs: MutRecBindingsPhase2A), (tpenv,_,uncheckedBindsRev) =
              let initialOuterState = (tpenv, 0, ([]: PreCheckingRecursiveBinding list))
              (initialOuterState, envMutRec, mutRecDefns) |||> MutRecShapes.mapFoldWithEnv (fun outerState envForDecls defns -> 
                let (tpenv,recBindIdx,uncheckedBindsRev) = outerState
                match defns with 
                | MutRecShape.Module _ ->  failwith "unreachable"
  