Do something better about re-exported symbols from another package

[waern]

Do something better about re-exported symbols from another package.

[igloo]

See also:

http://hackage.haskell.org/trac/ghc/ticket/1269

http://hackage.haskell.org/trac/ghc/ticket/2337

[waern]

To be able to display proper documentation for symbols from other packages, we need to store declarations in the .haddock files. We are currently waiting for GHC to provide Binary instances for declarations.

[waern]

We might not need to store anything in the .haddock files if we can reconstruct all declarations from the TyThings available in the .hi files. We already convert instances using a conversion function toHsType :: Type -> HsType Name. We could try to write a conversation function toHsDecl :: TyThing -> HsDecl Name.

The downside of this approach is that we loose the original declaration style. For example, we don't know if a data type was declared using GADT-style syntax (with a 'where' clause), or normal style.

[waern]

Thanks to Isaac Dupree and his Summer of Code project, this is now implemented. We are able to generate documentation of the same level of detail for re-exported symbols as we do normally (modulo syntactic differences).