Re: [GHC] #14217: Interface-file decls for large tuples

12 Sep 2017

      #14217: Interface-file decls for large tuples
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        Reporter:  crockeea          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by crockeea):

 Here's the code in question.

 {{{

 {-# LANGUAGE DataKinds             #-}
 {-# LANGUAGE FlexibleContexts      #-}
 {-# LANGUAGE PartialTypeSignatures #-}
 {-# LANGUAGE PolyKinds             #-}
 {-# LANGUAGE RebindableSyntax      #-}
 {-# LANGUAGE ScopedTypeVariables   #-}
 {-# LANGUAGE TypeFamilies          #-}
 {-# LANGUAGE TypeOperators         #-}

 {-# OPTIONS_GHC -fno-warn-partial-type-signatures #-}

 module Crypto.Lol.Applications.Tests.SHETests (tunnelTests) where

 import Control.Monad.Random

 import Crypto.Lol
 import Crypto.Lol.Applications.SymmSHE
 import Crypto.Lol.Tests

 import qualified Test.Framework as TF

 tunnelTests :: forall t r r' s s' zp zq gad . (_)
   => Proxy '(r,r',s,s',zp,zq) -> Proxy gad -> Proxy t -> TF.Test
 tunnelTests _ _ _ =
   let ptmr = Proxy::Proxy '(t,r,r',s,s',zp,zq,gad)
   in TF.testGroup (showType ptmr)
        [genTestArgs "Tunnel" prop_ringTunnel ptmr]

 prop_ringTunnel ::
   (TunnelHintCtx t e r s e' r' s' z zp zq gad,
    EncryptCtx t r r' z zp zq,
    DecryptUCtx t s s' z zp zq,
    e ~ FGCD r s)
   => PT (Cyc t r zp) -> SK (Cyc t r' z) -> SK (Cyc t s' z) -> Test
 '(t,r,r',s,s',zp,zq,gad)
 prop_ringTunnel x skin skout = undefined
 }}}

 bgamari: That's useful to know! The constraints on `prop_ringTunnel`
 (`TunnelHintCtx`, `EncryptCtx`, and `DecryptCtx`) are all (large)
 constraint synonyms. The offending line is actually `tunnelTests _ _ _ =`.
 Although the error in this ticket is killing compilation before I get a
 warning about the partial type signature (which would include the entire
 constraint list for `tunnelTests`), I know that the list is heinous --
 that's why I'm using PTSs in the first place! It wouldn't surprise me at
 all to know it had 64 items in it.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14217#comment:3
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