#2386: Splicing in constructors that are abstract from the point of view of the
splice point is unreliable
-------------------------------+--------------------------------------------
Reporter: batterseapower | Owner:
Type: bug | Status: new
Priority: normal | Component: Template Haskell
Version: 6.8.3 | Severity: normal
Keywords: | Testcase:
Architecture: x86_64 (amd64) | Os: MacOS X
-------------------------------+--------------------------------------------
Test1.hs:
{{{
{-# LANGUAGE TemplateHaskell #-}
module Main where
import Test2
main = putStrLn (show $(makeOne))
}}}
Test2.hs:
{{{
{-# LANGUAGE TemplateHaskell #-}
module Test2(ExportedAbstract, makeOne) where
data ExportedAbstract = Yay String | NonYay AnotherThing
data AnotherThing = Foo String
instance Show ExportedAbstract where
show _ = "Shown"
makeOne = [| Yay "Yep" |]
}}}
Compile this with optimizations:
{{{
ghc Test2.hs -O2
ghc --make Test1.hs
}}}
Results in:
{{{
$ ./Test1
Shown
}}}
Compile this without optimizations:
{{{
ghc Test2.hs -O0
ghc --make Test1.hs
}}}
Results in:
{{{
$ ghc --make Test1.hs
[2 of 2] Compiling Main ( Test1.hs, Test1.o )
Loading package base ... linking ... done.
Loading package pretty-1.0.0.0 ... linking ... done.
Loading package array-0.1.0.0 ... linking ... done.
Loading package packedstring-0.1.0.0 ... linking ... done.
Loading package containers-0.1.0.1 ... linking ... done.
Loading package template-haskell ... linking ... done.
Test1.hs:7:24:
Can't find interface-file declaration for data constructor Test2.Yay
Probable cause: bug in .hi-boot file, or inconsistent .hi file
Use -ddump-if-trace to get an idea of which file caused the error
In the first argument of `show', namely `$makeOne'
In the first argument of `putStrLn', namely `(show ($makeOne))'
In the expression: putStrLn (show ($makeOne))
}}}
Why is this? Because trimThing in TidyPgm makes data types abstract in
some circumstances, and it only happens if compiling a boot file or with
-O0!
I think this program should compile as the splicing is not a violation of
the abstractness of the data type: all the manipulation etc is still being
done by the defining module.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2386>
GHC <http://www.haskell.org/ghc/>
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