anchor.diff:  
   //
   [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
  -module internal StatefulChoice =
  +module StatefulChoice =
       /// The standard F# Array module, lifted into the StatefulChoice monad.
       [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
       module Array =
  
positive.code: 
  //
  [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
  module internal Either =
      /// The standard F# Array module, lifted into the Either monad.
      [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
      module Array =
          //
  
negative.code:                 | Choice1Of2 result ->
                      results.[index] <- result
                      index <- index + 1
              
              // Return the updated state along with the
              // result (or error, if set).
  