exprIsHNF should "look through" lets

[ghc-hetmet.git] / compiler / coreSyn / CoreUtils.lhs

diff --git a/compiler/coreSyn/CoreUtils.lhs b/compiler/coreSyn/CoreUtils.lhs
index 23eec49..d200f81 100644 (file)
--- a/compiler/coreSyn/CoreUtils.lhs
+++ b/compiler/coreSyn/CoreUtils.lhs
@@ -210,7 +210,7 @@ mkCoerce co expr
 --    if to_ty `coreEqType` from_ty
 --    then expr
 --    else 
-        ASSERT2(from_ty `coreEqType` (exprType expr), text "Trying to coerce" <+> text "(" <> ppr expr $$ text "::" <+> ppr (exprType expr) <> text ")" $$ ppr co $$ pprEqPred (coercionKind co))
+        WARN(not (from_ty `coreEqType` exprType expr), text "Trying to coerce" <+> text "(" <> ppr expr $$ text "::" <+> ppr (exprType expr) <> text ")" $$ ppr co $$ pprEqPred (coercionKind co))
          (Cast expr co)
 \end{code}
 
@@ -736,6 +736,7 @@ exprIsHNFlike is_con is_con_unf = is_hnf_like
     is_hnf_like (Cast e _)       = is_hnf_like e
     is_hnf_like (App e (Type _)) = is_hnf_like e
     is_hnf_like (App e a)        = app_is_value e [a]
+    is_hnf_like (Let _ e)        = is_hnf_like e  -- Lazy let(rec)s don't affect us
     is_hnf_like _                = False
 
     -- There is at least one value argument