Comments and an import-trim

[ghc-hetmet.git] / compiler / deSugar / Desugar.lhs

diff --git a/compiler/deSugar/Desugar.lhs b/compiler/deSugar/Desugar.lhs
index dc0e124..c2ee0a5 100644 (file)
--- a/compiler/deSugar/Desugar.lhs
+++ b/compiler/deSugar/Desugar.lhs
@@ -270,6 +270,9 @@ dsRule mod in_scope (L loc (HsRule name act vars lhs tv_lhs rhs fv_rhs))
              lhs_names = fn_name : nameSetToList (exprsFreeNames args)
                -- No need to delete bndrs, because
                -- exprsFreeNames finds only External names
+
+               -- A rule is an orphan only if none of the variables
+               -- mentioned on its left-hand side are locally defined
              orph = case filter (nameIsLocalOrFrom mod) lhs_names of
                        (n:ns) -> Just (nameOccName n)
                        []     -> Nothing