anchor.diff:  
       let private onAllSelections (ctx : ValidationContext) (onSelection : SelectionInfo -> ValidationResult<AstError>) =
           let rec traverseSelections selection = (onSelection selection) @@ (selection.SelectionSet |> collectResults traverseSelections)
  -        ctx.Definitions |> collectResults(fun def -> def.SelectionSet |> collectResults traverseSelections)
  +        ctx.Definitions |> collectResults (fun def -> def.SelectionSet |> collectResults traverseSelections)
   
       let rec private getFragSelectionSetInfo (visitedFragments : string list) (fragmentTypeInfo : FragmentTypeInfo) (fragmentSelectionSet : Selection list) (parentCtx : SelectionInfoContext) =
           match fragmentTypeInfo with
  
positive.code:                 if length > 1
                  then AstError.AsResult(sprintf "There are %i arguments with name '%s' defined in %s. Field arguments must be unique." length name fieldOrDirective, path)
                  else Success)
          selectionSet
          |> collectResults (fun selection ->
              let argsValid = validateArgs (sprintf "alias or field '%s'" selection.AliasOrName) selection.Path selection.Field.Arguments
              let directiveArgsValid = selection.Field.Directives |> collectResults (fun directive -> validateArgs (sprintf "directive '%s'" directive.Name) selection.Path directive.Arguments)
              let innerArgsValid = checkArgumentUniqueness selection.SelectionSet
              argsValid @@ directiveArgsValid @@ innerArgsValid)
  
      let internal validateArgumentUniqueness (ctx : ValidationContext) =
          ctx.Definitions
          |> collectResults (fun def -> checkArgumentUniqueness def.SelectionSet)
  
      let private checkRequiredArguments (schemaInfo : SchemaInfo) (selection : SelectionInfo) =
          let inputsValid =
  
negative.code:         fragmentTypeValid @@ (selection.SelectionSet |> collectResults checkFragmentOnCompositeType)
  
      let internal validateFragmentsOnCompositeTypes (ctx : ValidationContext) =
          onAllSelections ctx checkFragmentOnCompositeType
  
      let internal validateFragmentsMustBeUsed (ctx : ValidationContext) =
          let rec getSpreadNames (acc : Set<string>) =
  