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[ghc-hetmet.git] / compiler / simplCore / SimplUtils.lhs

diff --git a/compiler/simplCore/SimplUtils.lhs b/compiler/simplCore/SimplUtils.lhs
index 45ef88a..1fdde7f 100644 (file)
--- a/compiler/simplCore/SimplUtils.lhs
+++ b/compiler/simplCore/SimplUtils.lhs
@@ -758,11 +758,11 @@ postInlineUnconditionally env top_lvl bndr occ_info rhs unfolding
 --     in \y. ....case f of {...} ....
 -- Here f is used just once, and duplicating the case work is fine (exprIsCheap).
 -- But
--- * We can't preInlineUnconditionally because that woud invalidate
---   the occ info for b.  
--- * We can't postInlineUnconditionally because the RHS is big, and
---   that risks exponential behaviour
--- * We can't call-site inline, because the rhs is big
+--  - We can't preInlineUnconditionally because that woud invalidate
+--    the occ info for b.
+--  - We can't postInlineUnconditionally because the RHS is big, and
+--    that risks exponential behaviour
+--  - We can't call-site inline, because the rhs is big
 -- Alas!
 
   where
@@ -797,7 +797,7 @@ activeInline env id
 activeRule :: DynFlags -> SimplEnv -> Maybe (Activation -> Bool)
 -- Nothing => No rules at all
 activeRule dflags env
-  | not (dopt Opt_RewriteRules dflags)
+  | not (dopt Opt_EnableRewriteRules dflags)
   = Nothing    -- Rewriting is off
   | otherwise
   = case getMode env of
@@ -1425,6 +1425,11 @@ prepareDefault _ _ case_bndr (Just (tycon, inst_tys)) imposs_cons (Just deflt_rh
 
        _ -> return [(DEFAULT, [], deflt_rhs)]
 
+  | debugIsOn, isAlgTyCon tycon, [] <- tyConDataCons tycon
+  = pprTrace "prepareDefault" (ppr case_bndr <+> ppr tycon)
+       -- This can legitimately happen for type families
+        $ return [(DEFAULT, [], deflt_rhs)]
+
 --------- Catch-all cases -----------
 prepareDefault _dflags _env _case_bndr _bndr_ty _imposs_cons (Just deflt_rhs)
   = return [(DEFAULT, [], deflt_rhs)]