Why does GHC print 15-tuples but not 16-tuples?

Question

Why does this work

print (True, True, True, True, True, True, True, True, True, True, True, True, True, True, True)

while this does not

print (True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True)

Answer 1

Because there is Show instance for 15-tuple:

Prelude> :i (,,,,,,,,,,,,,,)
data (,,,,,,,,,,,,,,) a b c d e f g h i j k l m n o
  = (,,,,,,,,,,,,,,) a b c d e f g h i j k l m n o
    -- Defined in `GHC.Tuple'
<<skip>>
instance (Read a, Read b, Read c, Read d, Read e, Read f, Read g,
          Read h, Read i, Read j, Read k, Read l, Read m, Read n, Read o) =>
         Read (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
  -- Defined in `GHC.Read'
instance (Show a, Show b, Show c, Show d, Show e, Show f, Show g,
          Show h, Show i, Show j, Show k, Show l, Show m, Show n, Show o) =>
         Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
  -- Defined in `GHC.Show'

And there are no for 16-tuple:

Prelude> :i (,,,,,,,,,,,,,,,)
data (,,,,,,,,,,,,,,,) a b c d e f g h i j k l m n o p
  = (,,,,,,,,,,,,,,,) a b c d e f g h i j k l m n o p
    -- Defined in `GHC.Tuple'

See docs

AFAIK instances are hand-written somethere in ghc internal libraries, and it is unlikely anybody will need to show 16-tuple.