Running with -XNoAlternativeLayoutRule
Running with -XAlternativeLayoutRule

layout003.hs:11:4: error: [GHC-58481] parse error on input ‘|’
Running with -XAlternativeLayoutRule -XAlternativeLayoutRuleTransitional

layout003.hs:11:4: warning: [GHC-93617] [-Walternative-layout-rule-transitional (in -Wdefault)]
    transitional layout will not be accepted in the future:
    `|' at the same depth as implicit layout block