anchor.diff:              yield ldfld found
               yield brtrue's skipOnes
               yield dup
  -            yield ldfld colIndex
  +            yield ldfld colInfo
               yield ldc'i4 0
               yield blt's skip
               yield cil {
                   yield ldarg 1 // row
                   yield ldarg 0 // this
  -                yield ldfld colIndex // row, index
  +                yield ldfld colInfo // row, index
                   yield generalize2 primitive.Converter
                   yield stfld colValue
                   yield ldarg 0
  
positive.code:             yield ldarg 1 // column map
              yield ldstr column.Name
              yield call2 ColumnMap.ColumnMethod
              yield stfld colIndex
          }
      override __.DefineImpartKnowledgeToNext() =
          cil {
              yield ldarg 1
              yield castclass builder
              yield ldarg 0
              yield ldfld colIndex
              yield stfld colIndex
          }
      override __.DefineRead(skipOnes) =
          cil {
  
negative.code: open LicenseToCIL.Stack
  open LicenseToCIL.Ops
  open System
  open System.Collections.Generic
  open System.Reflection
  open System.Reflection.Emit
  
  