lookupTypeName does not support type operators not starting with :
The following non-working code (minus a missing import) was posted on stackoverflow:
IssueTH.hs
:
{-# LANGUAGE TemplateHaskell #-}
module IssueTH where
import Language.Haskell.TH
f :: Q [Dec]
f = do
Just n <- lookupTypeName "GHC.TypeLits.*"
return []
Issue.hs
:
{-# LANGUAGE TemplateHaskell #-}
module Issue where
import IssueTH
import GHC.TypeLits
$f
ghc Issue.hs
fails with message:
Pattern match failure in do expression at IssueTH.hs:7:5-10
This gives no error if *
is replaced by an alphanumeric type like Nat
. Similar tests seem to fail whenever attempting to look up a type operator with lookupTypeName
.
Trac metadata
Trac field | Value |
---|---|
Version | 7.10.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Template Haskell |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | oerjan |
Operating system | |
Architecture |