From 1c1decdb7d40705bf631757263b6d04cf5acc8d7 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Thu, 9 Dec 2021 22:12:02 +0100
Subject: [PATCH] Repair type error for dataflow assertions

---
 packages/core/src/runtime/actor.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/runtime/actor.ts b/packages/core/src/runtime/actor.ts
index b902426..e234370 100644
--- a/packages/core/src/runtime/actor.ts
+++ b/packages/core/src/runtime/actor.ts
@@ -371,7 +371,10 @@ export class Turn {
         f.actor.dataflowGraph.withSubject(b, b);
     }
 
-    assertDataflow(assertionFunction: () => {target: Ref, assertion: Assertion}) {
+    assertDataflow(assertionFunction: () => {
+        target: Ref | undefined,
+        assertion: Assertion | undefined
+    }) {
         let handle: Handle | undefined = void 0;
         let target: Ref | undefined = void 0;
         let assertion: Assertion | undefined = void 0;