diff --git a/src/Data/Syntax/Assignment.hs b/src/Data/Syntax/Assignment.hs
index 9166d9db0..059c6368d 100644
--- a/src/Data/Syntax/Assignment.hs
+++ b/src/Data/Syntax/Assignment.hs
@@ -74,6 +74,7 @@ module Data.Syntax.Assignment
 , showError
 , showExpectation
 , assign
+, assignBy
 , runAssignment
 , AssignmentState(..)
 , makeState