Internal error when splicing value constructed using typed template haskell

Related to #15833

Compiling Test.hs leads to an internal compiler error.

https://gist.github.com/f04a613bb5e20c241c5b91c2f38b8f06

{-# LANGUAGE TemplateHaskell #-}
{-# OPTIONS_GHC -ddump-splices #-}
module Test where

import qualified Compiler as C

main :: IO ()
main = $$(C.runQuery)

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications #-}
{-# OPTIONS_GHC -Wall #-}
module Compiler where

import Language.Haskell.TH

type QTExp a = Q (TExp a)

fix :: (a -> a) -> a
fix f = let x = f x in x

while ::
  forall m . Monoid m =>
  QTExp (IO m -> IO m) -> QTExp (IO m)
while b = [|| fix (\r -> whenM @(IO m) ($$b r)) ||]

whenM :: Monoid m => m ->  m
whenM _ = mempty

execOp :: forall m . Monoid m => QTExp (IO m)
execOp = while [|| \r -> $$(while @m [|| id ||]) >> r ||]

runQuery :: QTExp (IO ())
runQuery = execOp

Leads to the following internal errors even though Compiler type checked.

Prelude> :r
[1 of 2] Compiling Compiler         ( Compiler.hs, interpreted )
[2 of 2] Compiling Test             ( Test.hs, interpreted )
Test.hs:9:6-15: Splicing expression
    C.runQuery
  ======>
    C.fix
      (\ r_a7K7
         -> (C.whenM @(IO m_a7Gp))
              ((\ r_a7K8
                  -> ((C.fix (\ r_a7K9 -> (C.whenM @(IO m_a7Gp)) (id r_a7K9)))
                        >> r_a7K8))
                 r_a7K7))

Test.hs:9:6: error:
    • The exact Name ‘m’ is not in scope
        Probable cause: you used a unique Template Haskell name (NameU),
        perhaps via newName, but did not bind it
        If that's it, then -ddump-splices might be useful
    • In the result of the splice:
        $C.runQuery
      To see what the splice expanded to, use -ddump-splices
      In the Template Haskell splice $$(C.runQuery)
      In a stmt of a 'do' block: $$(C.runQuery)
  |
9 |   $$(C.runQuery)
  |      ^^^^^^^^^^

Test.hs:9:6: error:
    • The exact Name ‘m’ is not in scope
        Probable cause: you used a unique Template Haskell name (NameU),
        perhaps via newName, but did not bind it
        If that's it, then -ddump-splices might be useful
    • In the result of the splice:
        $C.runQuery
      To see what the splice expanded to, use -ddump-splices
      In the Template Haskell splice $$(C.runQuery)
      In a stmt of a 'do' block: $$(C.runQuery)
  |
9 |   $$(C.runQuery)
  |      ^^^^^^^^^^

Test.hs:9:6: error:
    • GHC internal error: ‘m’ is not in scope during type checking, but it passed the renamer
      tcl_env of environment: [a7K7 :-> Identifier[r_a7K7::a0, NotLetBound],
                               r5Fg :-> Identifier[main::IO (), TopLevelLet [] True]]
    • In the first argument of ‘IO’, namely ‘m’
      In the type ‘(IO m)’
      In the expression:
        (C.whenM @(IO m))
          ((\ r_a7K8
              -> ((C.fix (\ r_a7K9 -> (C.whenM @(IO m)) (id r_a7K9))) >> r_a7K8))
             r_a7K7)
  |
9 |   $$(C.runQuery)
  |

Trac metadata

Trac field	Value
Version	8.6.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
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Operating system
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