1 files changed, 25 insertions, 0 deletions
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerSumDefinitionTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerSumDefinitionTests.java
index ef67cb5..1120bbe 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerSumDefinitionTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerSumDefinitionTests.java
@@ -9,6 +9,7 @@ import org.zwobble.hobgoblin.compiler.ast.untyped.*;
 import org.zwobble.hobgoblin.compiler.builtins.NativeTypes;
 import org.zwobble.hobgoblin.compiler.sources.NullSource;
 import org.zwobble.hobgoblin.compiler.typechecker.errors.SubtypeIsMissingFieldError;
+import org.zwobble.hobgoblin.compiler.typechecker.errors.SumVariantMustBeStructError;
 import org.zwobble.hobgoblin.compiler.typechecker.errors.UnexpectedTypeError;
 import org.zwobble.hobgoblin.compiler.types.*;
 
@@ -149,6 +150,30 @@ public class TypeCheckerSumDefinitionTests {
     }
 
     @Test
+    public void variantMustBeStructType() {
+        var untyped = UntypedSumDefinitionNode.arbitrary()
+            .withName("X")
+            .withVariants(List.of(
+                UntypedSumVariantDefinitionNode.arbitrary()
+                    .withType(UntypedArb.typeLevelReference("Int32"))
+                    .build()
+            ))
+            .build();
+        var globalContext = TypeCheckerGlobalContext.initial();
+        globalContext.addNativeType(NativeTypes.INT_32);
+        globalContext.addNativeTypeConstructor(NativeTypes.BOX);
+        var namespaceContext = globalContext
+            .enterNamespace(NamespaceName.of("a", "b"));
+
+        var error = assertThrows(
+            SumVariantMustBeStructError.class,
+            () -> typeCheckNamespaceStatement(untyped, namespaceContext)
+        );
+
+        assertThat(error.variantType(), equalTo(NativeTypes.INT_32));
+    }
+
+    @Test
     public void fieldsAreTypeChecked() {
         var int32Type = SimpleNativeType.builtin("Int32");
         var int64Type = SimpleNativeType.builtin("Int64");