anchor.diff:  
                   preMembers @ postMembers
   
  -            //let _a,b = SplitTyconDefns cenv (tinfos @ [synTyconInfo]) tycons
  -
               let isConcrete = 
                   members |> List.exists (function 
                       | SynMemberDefn.Member(Binding(_,_,_,_,_,_,SynValData(Some memberFlags,_,_),_,_,_,_,_),_) -> not memberFlags.IsDispatchSlot 
  
positive.code: 
          | SynTypeDefnSigRepr.Simple(r,_) -> 
              let isAtOriginalTyconDefn = true
              let tyconCore = MutRecDefnsPhase1DataForTycon (synTyconInfo, r, implements1, false, false,isAtOriginalTyconDefn)
              tyconCore, (synTyconInfo,extraMembers) 
  
      let SplitMutRecSignatures mutRecSigs = mutRecSigs |> MutRecShapes.mapTycons SplitTyconSignature
  
      let private TcTyconSignatureMemberSpecs cenv parent envMutRec mutRecDefns =
          // TODO - this is only checking the tycons in the signatures, need to do the module and let elements too
          (envMutRec,mutRecDefns) ||> MutRecShapes.mapTyconsWithEnv (fun envForDecls ((tyconCore, (synTyconInfo,members)), _, _) -> 
              let tpenv = emptyUnscopedTyparEnv
              let (MutRecDefnsPhase1DataForTycon (_, _, _, _, _, isAtOriginalTyconDefn)) = tyconCore
              let (ComponentInfo(_,typars,cs,longPath, _, _, _,m)) = synTyconInfo
  
negative.code: 
      // Third phase: check and publish the supr types. Run twice, once before constraints are established
      // and once after
      let private TcTyconDefnCore_Phase1D_Phase1F_EstablishSuperTypesAndInterfaceTypes cenv tpenv inSig pass (envMutRec, mutRecDefns:MutRecShape<(_ * (Tycon * Attribs) option),_,_,_> list) = 
          let checkCxs = if (pass = SecondPass) then CheckCxs else NoCheckCxs
          let firstPass = (pass = FirstPass)
  
          // Publish the immediately declared interfaces. 
          let tyconWithImplementsL = 
              (envMutRec, mutRecDefns) ||> MutRecShapes.mapTyconsWithEnv (fun envinner (origInfo,tyconAndAttrsOpt)  -> 
                 match origInfo, tyconAndAttrsOpt with 
                 | (typeDefCore,_,_), Some (tycon, checkedAttrs) ->
                  let (MutRecDefnsPhase1DataForTycon(_,synTyconRepr,explicitImplements,_,_,_)) = typeDefCore
                  let m = tycon.Range
                  let tcref = mkLocalTyconRef tycon
                  let envinner = AddDeclaredTypars CheckForDuplicateTypars (tycon.Typars(m)) envinner
  