[GHC] #9113: Template Haskell should warn about non-exhaustive pattern matches

15 May 2014

      #9113: Template Haskell should warn about non-exhaustive pattern matches
-------------------------+-------------------------------------------------
       Reporter:  tvh    |             Owner:
           Type:  bug    |            Status:  new
       Priority:         |         Milestone:
  normal                 |           Version:  7.8.2
      Component:         |  Operating System:  Unknown/Multiple
  Template Haskell       |   Type of failure:  Incorrect warning at
       Keywords:         |  compile-time
   Architecture:         |         Test Case:
  Unknown/Multiple       |          Blocking:
     Difficulty:         |
  Unknown                |
     Blocked By:         |
Related Tickets:         |
-------------------------+-------------------------------------------------
 When using Typed Template Haskell, There are no warings for non-exhaustive
 patterns inside the quote.

 {{{
 {-# LANGUAGE TemplateHaskell #-}

 module Foo where

 import Language.Haskell.TH.Lib

 foo :: Maybe Int -> TExpQ Bool
 foo x = [||case x of
             Nothing -> False||]
 }}}

 Instead the warnings appear where the code is spliced.

 {{{
 {-# LANGUAGE TemplateHaskell #-}

 module Bar where

 import Foo

 x = $$(foo (Just 1))
 }}}

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9113
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler