GHC reports an exact Name is not in scope when quoting ANN

If you compile the following program:

{-# LANGUAGE TemplateHaskell #-}
module Bug where

$([d| x :: Int
      x = 42
      {-# ANN x "blah" #-}
    |])

You'll get:

$ /opt/ghc/8.10.3/bin/ghc Bug.hs
[1 of 1] Compiling Bug              ( Bug.hs, Bug.o, Bug.dyn_o )

Bug.hs:4:3: error:
    • The exact Name ‘x’ 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 annotation: {-# ANN x "blah" #-}
  |
4 | $([d| x :: Int
  |   ^^^^^^^^^^^^...

Which probably shouldn't happen. If you compile with -ddump-splices, it's more obvious what is happening:

Bug.hs:(4,3)-(7,6): Splicing declarations
    [d| {-# ANN x_age "blah" #-}
        
        x_age :: Int
        x_age = 42 |]
  ======>
    x_a25M :: Int
    x_a25M = 42
    {-# ANN x_age "blah" #-}

The name mentioned in the ANN (x_age) is not the same name mentioned in the function declaration (x_a25M). As for why this happens, I believe this code is responsible:

repAnnProv :: AnnProvenance Name -> MetaM (Core TH.AnnTarget)
repAnnProv (ValueAnnProvenance (L _ n))
  = do { MkC n' <- lift $ globalVar n  -- ANNs are allowed only at top-level
       ; rep2_nw valueAnnotationName [ n' ] }
repAnnProv (TypeAnnProvenance (L _ n))
  = do { MkC n' <- lift $ globalVar n
       ; rep2_nw typeAnnotationName [ n' ] }
repAnnProv ModuleAnnProvenance
  = rep2_nw moduleAnnotationName []

This turns the Core Name inside an ANN to a Template Haskell Name by way of globalVar, which allocates a fresh Template Haskell Name regardless of what other Names are in scope. I think that globalVar should actually be lookupLOcc instead. Indeed, this patch appears to fix the issue locally:

diff --git a/compiler/GHC/HsToCore/Quote.hs b/compiler/GHC/HsToCore/Quote.hs
index 767914127a..a6e1100419 100644
--- a/compiler/GHC/HsToCore/Quote.hs
+++ b/compiler/GHC/HsToCore/Quote.hs
@@ -848,11 +848,11 @@ repAnnD (L loc (HsAnnotation _ _ ann_prov (L _ exp)))
        ; return (loc, dec) }
 
 repAnnProv :: AnnProvenance Name -> MetaM (Core TH.AnnTarget)
-repAnnProv (ValueAnnProvenance (L _ n))
-  = do { MkC n' <- lift $ globalVar n  -- ANNs are allowed only at top-level
+repAnnProv (ValueAnnProvenance n)
+  = do { MkC n' <- lookupLOcc n  -- ANNs are allowed only at top-level
        ; rep2_nw valueAnnotationName [ n' ] }
-repAnnProv (TypeAnnProvenance (L _ n))
-  = do { MkC n' <- lift $ globalVar n
+repAnnProv (TypeAnnProvenance n)
+  = do { MkC n' <- lookupLOcc n
        ; rep2_nw typeAnnotationName [ n' ] }
 repAnnProv ModuleAnnProvenance
   = rep2_nw moduleAnnotationName []

The comment says "ANNs are allowed only at top-level", but I don't think that's relevant here. After all, standalone kind signatures are also allowed only at the top level, but repKiSigD still uses lookupLOcc.