Running with -XNoAlternativeLayoutRule
Running with -XAlternativeLayoutRule

layout006.hs:12:2: error: parse error on input ‘|’
Running with -XAlternativeLayoutRule -XAlternativeLayoutRuleTransitional

layout006.hs:12:2: warning: [-Walternative-layout-rule-transitional (in -Wdefault)]
    transitional layout will not be accepted in the future:
    `|' at the same depth as implicit layout block