Allow reify to find top-level bindings in later declaration groups

Some time ago, at Tweag we were considering inspecting the types of declarations added with addTopDecls like this:

{-# LANGUAGE TemplateHaskell #-}
import Language.Haskell.TH.Syntax

main :: IO ()
main =
    $(do
      ds <- [d| f = True |]
      addTopDecls ds
      addModFinalizer $ do
        VarI _ t _ <- reify (mkName "f")
        runIO $ hPutStrLn stderr ("f :: " ++ show t)
      [| return () |]
     )

f is not in scope when the finalizer is added. But its type would be known when the finalizer runs.

This worked before the patch https://phabricator.haskell.org/D2286. There is a patch that we submitted to address this https://phabricator.haskell.org/D2519, but it turned out later that we didn't need it and the patch was considered less than ideal.

We are opening this ticket to keep track of the nuance in case someone finds the patch useful later.

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	mboes, simonpj
Operating system
Architecture