Matching cases in SpecConstr and Rules

[ghc-hetmet.git] / compiler / specialise / SpecConstr.lhs

diff --git a/compiler/specialise/SpecConstr.lhs b/compiler/specialise/SpecConstr.lhs
index 3a7e221..4c0d927 100644 (file)
--- a/compiler/specialise/SpecConstr.lhs
+++ b/compiler/specialise/SpecConstr.lhs
@@ -1436,11 +1436,18 @@ argToPat env in_scope val_env (Note _ arg) arg_occ
 
 argToPat env in_scope val_env (Let _ arg) arg_occ
   = argToPat env in_scope val_env arg arg_occ
+       -- See Note [Matching lets] in Rule.lhs
        -- Look through let expressions
-       -- e.g.         f (let v = rhs in \y -> ...v...)
-       -- Here we can specialise for f (\y -> ...)
+       -- e.g.         f (let v = rhs in (v,w))
+       -- Here we can specialise for f (v,w)
        -- because the rule-matcher will look through the let.
 
+{- Disabled; see Note [Matching cases] in Rule.lhs
+argToPat env in_scope val_env (Case scrut _ _ [(_, _, rhs)]) arg_occ
+  | exprOkForSpeculation scrut -- See Note [Matching cases] in Rule.hhs
+  = argToPat env in_scope val_env rhs arg_occ
+-}
+
 argToPat env in_scope val_env (Cast arg co) arg_occ
   | not (ignoreType env ty2)
   = do { (interesting, arg') <- argToPat env in_scope val_env arg arg_occ