[GHC] #8993: Fold NullaryTypeClasses into MPTC

[GHC]

#8993: Fold NullaryTypeClasses into MPTC
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        Reporter:  owst              |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:  7.10.1
       Component:  Compiler          |          Version:  7.8.2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Changes (by hvr):

 * status:  closed => new
 * resolution:  fixed =>


Comment:

 It seems that currently `NullaryTypeClasses` has no effect anymore?
 Specifically, `make WAY=normal TEST=TcNullaryTC` fails with

 {{{
 =====> TcNullaryTC(normal) 2009 of 4031 [0, 0, 0]
 cd ./typecheck/should_run && '/home/hvr/Haskell/GHC/ghc/inplace/bin/ghc-
 stage2' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-
 package-db -rtsopts -fno-ghci-history -o TcNullaryTC TcNullaryTC.hs
 >TcNullaryTC.comp.stderr 2>&1
 Compile failed (status 256) errors were:

 TcNullaryTC.hs:1:14: Warning:
     -XNullaryTypeClasses is deprecated: use -XMultiParamTypeClasses or
 pragma {-# LANGUAGE MultiParamTypeClasses #-} instead
 [1 of 1] Compiling Main             ( TcNullaryTC.hs, TcNullaryTC.o )

 TcNullaryTC.hs:5:1:
     No parameters for class ‘R’
     (Use MultiParamTypeClasses to allow no-parameter classes)
     In the class declaration for ‘R’

 *** unexpected failure for TcNullaryTC(normal)
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8993#comment:7>
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