Error found:
in module InstanceChains.BothUnknownAndMatch
at tests/purs/failing/InstanceChainBothUnknownAndMatch.purs:17:13 - 17:55 (line 17, column 13 - line 17, column 55)

  No type class instance was found for
                                                         
    InstanceChains.BothUnknownAndMatch.Same (RProxy      
                                               ( m :: Int
                                               , u :: t3 
                                               )         
                                            )            
                                            (RProxy      
                                               ( m :: Int
                                               , u :: Int
                                               )         
                                            )            
                                            t4           
                                                         

while applying a function same
  of type Same @Type @Type t0 t1 t2 => t0 -> t1 -> SProxy t2
  to argument RProxy
while inferring the type of same RProxy
in value declaration example

where t3 is a rigid type variable
        bound at (line 0, column 0 - line 0, column 0)
      t4 is an unknown type
      t0 is an unknown type
      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.