<div dir="ltr"><div>Yes, but it is not feasible before GHC 8.6, due to needing GHC >= 8.2 for bootstrapping.<br><br></div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On 22 November 2017 at 15:26, GHC <span dir="ltr"><<a href="mailto:ghc-devs@haskell.org" target="_blank">ghc-devs@haskell.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">#14490: TTG Snags<br>
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        Reporter:  alanz             |                Owner:  (none)<br>
            Type:  bug               |               Status:  new<br>
        Priority:  normal            |            Milestone:<br>
       Component:  Compiler          |              Version:  8.3<br>
</span>      Resolution:                    |             Keywords:<br>
Operating System:  Unknown/Multiple  |         Architecture:<br>
                                     |  Unknown/Multiple<br>
 Type of failure:  None/Unknown      |            Test Case:<br>
<span class="">      Blocked By:                    |             Blocking:<br>
 Related Tickets:  #14482            |  Differential Rev(s):<br>
       Wiki Page:                    |<br>
  ImplementingTreesThatGrow          |<br>
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<br>
</span>Comment (by Shayan-Najd):<br>
<span class=""><br>
 > So making a Data instance per concrete version may be the best way to<br>
 go. Plan B.<br>
<br>
</span> Regardless of the GHC version we use, the question is whether Plan B<br>
 really fixes the build-time problem. Can we test it?<br>
<span class="HOEnZb"><font color="#888888"><br>
--<br>
Ticket URL: <<a href="http://ghc.haskell.org/trac/ghc/ticket/14490#comment:31" rel="noreferrer" target="_blank">http://ghc.haskell.org/trac/<wbr>ghc/ticket/14490#comment:31</a>><br>
</font></span><div class="HOEnZb"><div class="h5">GHC <<a href="http://www.haskell.org/ghc/" rel="noreferrer" target="_blank">http://www.haskell.org/ghc/</a>><br>
The Glasgow Haskell Compiler<br>
</div></div></blockquote></div><br></div>