Error found:
in module Main
at tests/purs/failing/RowLacks.purs:16:9 - 16:68 (line 16, column 9 - line 16, column 68)

  No type class instance was found for
                                
    Prim.Row.Lacks "x"          
                   ( x :: Int   
                   , y :: Int   
                   , z :: String
                   )            
                                

while applying a function lacksX
  of type Lacks @Type "x" t0 => RProxy t0 -> RProxy (() @Type)
  to argument RProxy
while checking that expression lacksX RProxy
  has type RProxy (() @Type)
in value declaration test1

where t0 is an unknown type

See https://github.com/purescript/documentation/blob/master/errors/NoInstanceFound.md for more information,
or to contribute content related to this error.