1 files changed, 3 insertions, 0 deletions
diff --git a/src/core.sml b/src/core.sml
index 78f0cce0..badb08ea 100644
--- a/src/core.sml
+++ b/src/core.sml
@@ -34,6 +34,7 @@ datatype kind' =
        | KArrow of kind * kind
        | KName
        | KRecord of kind
+       | KUnit
 
 withtype kind = kind' located
 
@@ -54,6 +55,8 @@ datatype con' =
        | CConcat of con * con
        | CFold of kind * kind
 
+       | CUnit
+
 withtype con = con' located
 
 datatype exp' =