[GHC] #12415: Fancy BinIface encoding for tuples is broken for constraint tuples

[GHC]

#12415: Fancy BinIface encoding for tuples is broken for constraint tuples
-------------------------------------+-------------------------------------
           Reporter:  bgamari        |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  #12357
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 We have a special way of encoding tuple-related names in the interface
 file symbol table. See `Note [Symbol table representation of names]`.

 However, it was broken for constraint tuples by
 ffc21506894c7887d3620423aaf86bc6113a1071. The problem is very similar to
 the one which prevented us from encoding tuple type representations in
 #12357 (see ticket:12357#comment:31). By unwiring constraint tuples it
 becomes harder to identify them for special handling during serialization.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12415>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler