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

[GHC]

#14217: Interface-file decls for large tuples
-------------------------------------+-------------------------------------
        Reporter:  crockeea          |                Owner:  (none)
            Type:  bug               |               Status:  merge
        Priority:  high              |            Milestone:  8.2.2
       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:                    |
-------------------------------------+-------------------------------------
Changes (by simonpj):

 * status:  new => merge


Comment:

 Ah yes.  I failed to mention the ticket, sorry.  The commit is
 {{{
 commit 3c74a51232813eb733b27c43c94ce005112a0ddb
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Thu Sep 21 17:35:11 2017 +0100

     Deal with large extra-contraints wildcards

     For reasons explained in TcHsType
     Note [Extra-constraint holes in partial type signatures],
     if we had
       f :: (_) => blahs
     and the '_' was filled in by more than a 62-tuple of contraints,
     GHC crashed.

     The same Note explains the hacky solution I have adopted to
     evade this.  Maybe there is some better way, but I couldn't
     see one that didn't involve a great deal of work. And the problem
     is a very narrow one!  If the hack bites us we'll need to think
     again.

  compiler/prelude/TysWiredIn.hs                     |  7 +-
  compiler/typecheck/TcBinds.hs                      | 18 ++--
  compiler/typecheck/TcHsType.hs                     | 52 +++++++++++-
  compiler/typecheck/TcMType.hs                      |  7 +-
  .../tests/partial-sigs/should_compile/T14217.hs    | 41 +++++++++
  .../partial-sigs/should_compile/T14217.stderr      | 99
 ++++++++++++++++++++++
  testsuite/tests/partial-sigs/should_compile/all.T  |  1 +
  7 files changed, 210 insertions(+), 15 deletions(-)
 }}}
 And yes we could merge it.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14217#comment:7>
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