On Tue, Jun 25, 2019 at 12:43:03PM +0200, Johannes Waldmann wrote: > But it's not in the grammar? > > alts → alt1 ; … ; altn (n ≥ 1) > > https://www.haskell.org/onlinereport/haskell2010/haskellch3.html#x8-460003.13 The rule "alt" allows "(empty alternative)"