diff options
Diffstat (limited to 'compiler/rename')
| -rw-r--r-- | compiler/rename/RnPat.hs | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/compiler/rename/RnPat.hs b/compiler/rename/RnPat.hs index 8c7831497b..f44d492fe0 100644 --- a/compiler/rename/RnPat.hs +++ b/compiler/rename/RnPat.hs @@ -588,23 +588,13 @@ rnHsRecFields ctxt mk_arg (HsRecFields { rec_flds = flds, rec_dotdot = dotdot }) ; con_fields <- lookupConstructorFields con ; when (null con_fields) (addErr (badDotDotCon con)) ; let present_flds = map (occNameFS . rdrNameOcc) $ getFieldLbls flds - parent_tc = find_tycon rdr_env con -- For constructor uses (but not patterns) - -- the arg should be in scope (unqualified) - -- ignoring the record field itself + -- the arg should be in scope locally; + -- i.e. not top level or imported -- Eg. data R = R { x,y :: Int } -- f x = R { .. } -- Should expand to R {x=x}, not R{x=x,y=y} - arg_in_scope lbl - = rdr `elemLocalRdrEnv` lcl_env - || notNull [ gre | gre <- lookupGRE_RdrName rdr rdr_env - , case gre_par gre of - ParentIs p -> Just p /= parent_tc - FldParent p _ -> Just p /= parent_tc - PatternSynonym -> False - NoParent -> True ] - where - rdr = mkVarUnqual lbl + arg_in_scope lbl = mkVarUnqual lbl `elemLocalRdrEnv` lcl_env dot_dot_gres = [ (lbl, sel, head gres) | fl <- con_fields @@ -646,11 +636,12 @@ rnHsRecFields ctxt mk_arg (HsRecFields { rec_flds = flds, rec_dotdot = dotdot }) | Just gre <- lookupGRE_Name env con_name = case gre_par gre of ParentIs p -> Just p - _ -> Nothing + _ -> Nothing -- Can happen if the con_name + -- is for a pattern synonym | otherwise = Nothing - -- This can happen if the datacon is not in scope - -- and we are in a TH splice (Trac #12130) + -- Data constructor not lexically in scope at all + -- See Note [Disambiguation and Template Haskell] dup_flds :: [[RdrName]] -- Each list represents a RdrName that occurred more than once @@ -659,6 +650,22 @@ rnHsRecFields ctxt mk_arg (HsRecFields { rec_flds = flds, rec_dotdot = dotdot }) (_, dup_flds) = removeDups compare (getFieldLbls flds) +{- Note [Disambiguation and Template Haskell] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Consider (Trac #12130) + module Foo where + import M + b = $(funny) + + module M(funny) where + data T = MkT { x :: Int } + funny :: Q Exp + funny = [| MkT { x = 3 } |] + +When we splice, neither T nor MkT are lexically in scope, so find_tycon will +fail. But there is no need for diambiguation anyway, so we just return Nothing +-} + rnHsRecUpdFields :: [LHsRecUpdField RdrName] -> RnM ([LHsRecUpdField Name], FreeVars) |