diff --git a/src/Core/HindleyMilner.hs b/src/Core/HindleyMilner.hs
index 0897ece..e159d8d 100644
--- a/src/Core/HindleyMilner.hs
+++ b/src/Core/HindleyMilner.hs
@@ -108,7 +108,7 @@ addConstraint t u = _1 %= ((t, u):)
 
 -- | Unify a list of constraints, meaning that pairs between types are turned
 -- into pairs of type variables and types. A useful thought model is to think of
--- it like solving an equation such that the unknown variable is the left-hand
+-- it as solving an equation such that the unknown variable is the left-hand
 -- side.
 
 unify :: [Constraint] -> HMError Context'
diff --git a/src/Core/Syntax.hs b/src/Core/Syntax.hs
index fab3170..1e99723 100644
--- a/src/Core/Syntax.hs
+++ b/src/Core/Syntax.hs
@@ -58,6 +58,7 @@ data Type = TyInt
           | TyFun
           | TyVar Name
           | TyApp Type Type
+          | TyCon Name
           deriving (Show, Read, Lift, Eq)
 
 type TyCon = Name