Prevent singleton struct from being generic

1 files changed, 20 insertions, 4 deletions

diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
index 1de6cbf..fa913fa 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
@@ -6,11 +6,13 @@ import org.zwobble.hobgoblin.compiler.ast.typed.TypedStructDefinitionNode;
 import org.zwobble.hobgoblin.compiler.ast.typed.TypedStructFieldDefinitionNode;
 import org.zwobble.hobgoblin.compiler.ast.typed.TypedTypeLevelExpressionNode;
 import org.zwobble.hobgoblin.compiler.ast.untyped.*;
+import org.zwobble.hobgoblin.compiler.typechecker.errors.SingletonStructCannotHaveTypeParamsError;
 import org.zwobble.hobgoblin.compiler.types.*;
 
 import java.util.List;
 import java.util.Optional;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.zwobble.hobgoblin.compiler.typechecker.TypeCheckerTesting.typeCheckNamespaceStatement;
 import static org.zwobble.hobgoblin.compiler.types.TypeMatchers.isField;
 import static org.zwobble.precisely.AssertThat.assertThat;
@@ -48,6 +50,7 @@ public class TypeCheckerStructDefinitionTests {
                 UntypedTypeParamNode.arbitrary().withName("A").build(),
                 UntypedTypeParamNode.arbitrary().withName("B").build()
             )))
+            .withFields(List.of())
             .build();
         var context = TypeCheckerContextArb.namespaceContext(NamespaceName.of("a", "b"));
 
@@ -130,15 +133,11 @@ public class TypeCheckerStructDefinitionTests {
 
     @Test
     public void singletonStructHasNoFields() {
-        var int32Type = SimpleNativeType.builtin("Int32");
-        var int64Type = SimpleNativeType.builtin("Int64");
         var untyped = UntypedStructDefinitionNode.arbitrary()
             .withName("X")
             .withFields(Optional.empty())
             .build();
         var globalContext = TypeCheckerGlobalContext.initial();
-        globalContext.addNativeType(int32Type);
-        globalContext.addNativeType(int64Type);
         var namespaceName = NamespaceName.of("a", "b");
         var namespaceContext = globalContext.enterNamespace(namespaceName);
 
@@ -160,6 +159,23 @@ public class TypeCheckerStructDefinitionTests {
     }
 
     @Test
+    public void singletonStructCannotHaveTypeParams() {
+        var untyped = UntypedStructDefinitionNode.arbitrary()
+            .withName("X")
+            .withTypeParams(List.of(UntypedTypeParamNode.arbitrary().build()))
+            .withFields(Optional.empty())
+            .build();
+        var globalContext = TypeCheckerGlobalContext.initial();
+        var namespaceName = NamespaceName.of("a", "b");
+        var namespaceContext = globalContext.enterNamespace(namespaceName);
+
+        assertThrows(
+            SingletonStructCannotHaveTypeParamsError.class,
+            () -> typeCheckNamespaceStatement(untyped, namespaceContext)
+        );
+    }
+
+    @Test
     public void whenStructDefinitionHasTypeParamsThenTypeParamsAreBoundWithinStructDefinition() {
         var untyped = UntypedStructDefinitionNode.arbitrary()
             .withName("X")