Error found:
in module LacksWithSubGoal
at tests/purs/failing/LacksWithSubGoal.purs:14:11 - 14:33 (line 14, column 11 - line 14, column 33)

  No type class instance was found for
                          
    Prim.Row.Lacks "hello"
                   r0     
                          

while solving type class constraint
                           
  Prim.Row.Lacks "hello"   
                 ( k :: Int
                 | r0      
                 )         
                           
while applying a function union
  of type Lacks @Type t1 t2 => S t1 -> R t2
  to argument S
while checking that expression union S
  has type R           
             ( k :: Int
             | r0      
             )         
in value declaration example

where r0 is a rigid type variable
        bound at (line 14, column 11 - line 14, column 33)
      t1 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.