Error found:
in module Main
at tests/purs/failing/RowLacks.purs:16:9 - 16:66 (line 16, column 9 - line 16, column 66)

  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 @t1 "x" t2 => Proxy @(Row t1) t2 -> Proxy @(Row t3) (() @t3)
  to argument Proxy
while checking that expression lacksX Proxy
  has type Proxy @(Row t0) (() @t0)
in value declaration test1

where t0 is an unknown type
      t1 is an unknown type
      t3 is an unknown type
      t2 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.