Add subtyping for bottom type

1 files changed, 13 insertions, 1 deletions

diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java
index c9576191..b73011ce 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java
@@ -8,6 +8,18 @@ public class TypeCheckerSubTyping {
     }
 
     static boolean isSubType(Type subType, Type superType, TypeCheckerContext context) {
-        return superType == Types.TOP || subType.equals(superType);
+        if (superType == Types.TOP) {
+            return true;
+        }
+
+        if (subType == Types.BOTTOM) {
+            return true;
+        }
+
+        if (subType.equals(superType)) {
+            return true;
+        }
+
+        return false;
     }
 }