1 files changed, 25 insertions, 0 deletions
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeInfosTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeInfosTests.java
index 3a84923d..71386dfd 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeInfosTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeInfosTests.java
@@ -1,7 +1,11 @@
 package org.shedlang.compiler.typechecker;
 
 import org.junit.jupiter.api.Test;
+import org.shedlang.compiler.types.NamespaceName;
+import org.shedlang.compiler.types.SumTypeInfo;
+import org.shedlang.compiler.types.Type;
 import org.shedlang.compiler.types.Types;
+import org.shedlang.compiler.util.P;
 
 import static org.zwobble.precisely.AssertThat.assertThat;
 import static org.zwobble.precisely.Matchers.equalTo;
@@ -19,4 +23,25 @@ public class TypeInfosTests {
             equalTo(Types.TOP)
         ));
     }
+
+    @Test
+    public void supertypesOfSumVariantIncludeSumType() {
+        var namespaceName = NamespaceName.of("Example", "Project");
+        var sumType = Types.sum(namespaceName, "Sum");
+        var variantType1 = Types.struct(namespaceName, "Variant1");
+        var variantType2 = Types.struct(namespaceName, "Variant2");
+        var typeInfos = TypeInfos.EMPTY
+            .addSumTypeInfo(sumType, new SumTypeInfo(P.orderedSet(
+                variantType1,
+                variantType2
+            )));
+
+        var supertypes = typeInfos.supertypes(variantType2);
+
+        assertThat(supertypes, isSequence(
+            equalTo(variantType2),
+            equalTo(sumType),
+            equalTo(Types.TOP)
+        ));
+    }
 }