Re: [GHC] #14343: bad pretty-printing of types with promoted data types

8 Jun 2018

      #14343: bad pretty-printing of types with promoted data types
-------------------------------------+-------------------------------------
        Reporter:  lspitzner         |                Owner:  andreash
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4746
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"767536ccf95d8352d146b6544857b28d9c42937e/ghc" 767536c/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="767536ccf95d8352d146b6544857b28d9c42937e"
 Fix unparseable pretty-printing of promoted data cons

 Previously we would print code which would not round-trip:
 ```
...
:set -XDataKinds
:set -XPolyKinds
data Proxy k = Proxy
_ :: Proxy '[ 'True ]
 error:
   Found hole: _ :: Proxy '['True]
_ :: Proxy '['True]
 error:
     Invalid type signature: _ :: ...
     Should be of form <variable> :: <type>

Test Plan: Validate with T14343

Reviewers: RyanGlScott, goldfire, bgamari, tdammers

Reviewed By: RyanGlScott, bgamari

Subscribers: tdammers, rwbarton, thomie, carter

GHC Trac Issues: #14343

Differential Revision: https://phabricator.haskell.org/D4746
}}}

-- 
Ticket URL: &lt;http://ghc.haskell.org/trac/ghc/ticket/14343#comment:7>
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