[GHC] #15627: Absent unlifted bindings

[GHC]

#15627: Absent unlifted bindings
-------------------------------------+-------------------------------------
        Reporter:  sgraf             |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  ⊥
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #9279 #4328       |  Differential Rev(s):
  #11126                             |
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by simonpj):

 Ah I see. The problem is that we are using `Literal` in `IfaceSyn`, and
 that is biting us here; it would be more consistent to have
 `IfaceLiteral`.  If we did we could have
 {{{
 data IfaceLiteral
  = ...
  | RubbishLit IfaceType
  | LitNumber LitNumType Integer   -- No Type here; we reconstruct it in
 tcIfaceLit
                                   -- Avoids the smelly error-thunk in the
 Binary get
  ...
 }}}
 It's annoying that `Literal` and `IfaceLiteral` would be almost the same;
 some boilerplate converting to and fro.  But it's ''simple'' boilerplate,
 and uniform with everything else.  And it avoids that nasty error thunk in
 the binary instance of Literal.

 I suppose that a polymorphic literal as you suggest would be OK.  You
 could avoid the levity polymorphism by retaining `MachNullAddr`.

 I'm not sure which I prefer.  The `IfaceLiteral` story is less clever, and
 thus perhaps preferable.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15627#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler