[Template-haskell] panic: addImpDecls

[Simon Peyton-Jones]

Strange.  GHC just doesn't allow nested declaration splices -- and gives
a horrible message to boot.  I'm not sure why I hadn't even registered
that point.

Turns out that the way to fix this is closely connected with preparatory
work towards producing *typed* TH syntax trees.

TH has grown quite a long to-do list in the last month.  I'll try to do
something about it before our Xmas release of 6.4.  How urgent is this
particular thing for you?

Simon

| -----Original Message-----
| From: template-haskell-bounces at haskell.org
[mailto:template-haskell-bounces at haskell.org] On
| Behalf Of Ian Lynagh
| Sent: 21 November 2004 23:59
| To: template-haskell at haskell.org
| Subject: [Template-haskell] panic: addImpDecls
| 
| 
| Hi all,
| 
| If I have
| 
|     module Q () where
| 
|     $( [d|
|              $( [d| foo = 'c' |] )
|          |]
|      )
| 
| or even
| 
|     module Q () where
| 
|     $( [d|
|              $( [] )
|          |]
|      )
| 
| then "ghc -fth --make Q.hs" gives me:
| 
| ghc-6.3: panic! (the `impossible' happened, GHC version 6.3):
|         addImpDecls
| 
| 
| Thanks
| Ian
| 
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