Avoid false redundant import warning with DisambiguateRecordFields

Fixes #17853. We mustn't discard the result of pickGREs, because doing
so might lead to incorrect redundant import warnings.

1 files changed, 8 insertions, 6 deletions

diff --git a/compiler/GHC/Rename/Env.hs b/compiler/GHC/Rename/Env.hs
index 48ec8db86c..4b5d5d7af3 100644
--- a/compiler/GHC/Rename/Env.hs
+++ b/compiler/GHC/Rename/Env.hs
@@ -502,13 +502,15 @@ lookupRecFieldOcc mb_con rdr_name
        ; env <- getGlobalRdrEnv
        ; let lbl      = occNameFS (rdrNameOcc rdr_name)
              mb_field = do fl <- find ((== lbl) . flLabel) flds
-                           -- We have the label, now check it is in
-                           -- scope (with the correct qualifier if
-                           -- there is one, hence calling pickGREs).
+                           -- We have the label, now check it is in scope.  If
+                           -- there is a qualifier, use pickGREs to check that
+                           -- the qualifier is correct, and return the filtered
+                           -- GRE so we get import usage right (see #17853).
                            gre <- lookupGRE_FieldLabel env fl
-                           guard (not (isQual rdr_name
-                                         && null (pickGREs rdr_name [gre])))
-                           return (fl, gre)
+                           if isQual rdr_name
+                             then do gre' <- listToMaybe (pickGREs rdr_name [gre])
+                                     return (fl, gre')
+                              else return (fl, gre)
        ; case mb_field of
            Just (fl, gre) -> do { addUsedGRE True gre
                                 ; return (flSelector fl) }