anchor.diff:      | PtrTypesOK
       | PtrTypesNotOK
   
  -let GenReadOnlyAttribute (g: TcGlobals) = mkILCustomAttribute (g.attrib_IsReadOnlyAttribute.TypeRef, [], [], [])
  +let GenReadOnlyAttribute (g: TcGlobals) =
  +    mkILCustomAttribute (g.attrib_IsReadOnlyAttribute.TypeRef, [], [], [])
   
   let GenReadOnlyAttributeIfNecessary (g: TcGlobals) ty =
       let add = isInByrefTy g ty && g.attrib_IsReadOnlyAttribute.TyconRef.CanDeref
  
positive.code: 
              mkILNonGenericInstanceMethod (ilMethName, reprAccess, [], ilReturn, body)
  
      ilMethodDef
          .With(customAttrs = mkILCustomAttrs customAttrs)
          .WithSpecialName
  
  /// Choose the constructor parameter names for fields
  let ChooseParamNames fieldNamesAndTypes =
  
negative.code:             let ilMethods =
                  [
                      for propName, fldName, fldTy in flds ->
                          let attrs = if isStruct then [ GenReadOnlyAttribute g ] else []
                          mkLdfldMethodDef ("get_" + propName, ILMemberAccess.Public, false, ilTy, fldName, fldTy, attrs)
                      yield! genToStringMethod ilTy
                  ]
  