From f4faaed464d2d0bd61fb0f0b098c0f084aac5493 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@me.com>
Date: Tue, 23 Oct 2018 09:31:11 -0400
Subject: [PATCH] Define upcasting on Eff.

---
 src/Analysis/Abstract/Graph.hs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/Analysis/Abstract/Graph.hs b/src/Analysis/Abstract/Graph.hs
index de95c331c..bc67fb68c 100644
--- a/src/Analysis/Abstract/Graph.hs
+++ b/src/Analysis/Abstract/Graph.hs
@@ -160,6 +160,9 @@ eavesdrop :: (HFunctor eff, Carrier sig m, Member eff sig, Applicative m)
           -> m a
 eavesdrop m f = runEavesdropC f (interpret m)
 
+upcast :: Eff m a -> Eff (EavesdropC eff (Eff m)) a
+upcast m = Eff (\ k -> EavesdropC (\ f -> m >>= runEavesdropC f . k))
+
 newtype EavesdropC eff m a = EavesdropC ((forall x . eff m (m x) -> m ()) -> m a)
 
 runEavesdropC :: (forall x . eff m (m x) -> m ()) -> EavesdropC eff m a -> m a