Fix #19377 by using lookupLOcc when desugaring TH-quoted ANNswip/T19377

Previously, the desugarer was looking up names referenced in TH-quoted `ANN`s
by using `globalVar`, which would allocate a fresh TH `Name`. In effect, this
would prevent quoted `ANN`s from ever referencing the correct identifier
`Name`, leading to #19377. The fix is simple: instead of `globalVar`, use
`lookupLOcc`, which properly looks up the name of the in-scope identifier.

Fixes #19377.

1 files changed, 10 insertions, 0 deletions

diff --git a/testsuite/tests/th/T19377.hs b/testsuite/tests/th/T19377.hs
new file mode 100644
index 0000000000..e27149ccfe
--- /dev/null
+++ b/testsuite/tests/th/T19377.hs
@@ -0,0 +1,10 @@
+{-# LANGUAGE TemplateHaskell #-}
+module T19377 where
+
+$([d| x :: Int
+      x = 42
+      {-# ANN x "blah" #-}
+
+      data Y
+      {-# ANN type Y "yargh" #-}
+    |])