1 files changed, 45 insertions, 0 deletions
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerConstructedTypeTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerConstructedTypeTests.java
index fa511ba..09c0f8c 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerConstructedTypeTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerConstructedTypeTests.java
@@ -3,10 +3,12 @@ package org.zwobble.hobgoblin.compiler.typechecker;
 import org.junit.jupiter.api.Test;
 import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedArb;
 import org.zwobble.hobgoblin.compiler.sources.NullSource;
+import org.zwobble.hobgoblin.compiler.typechecker.errors.WrongNumberOfTypeLevelArgsError;
 import org.zwobble.hobgoblin.compiler.types.*;
 
 import java.util.List;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.zwobble.hobgoblin.compiler.ast.typed.TypedNodeMatchers.isTypedConstructedTypeNode;
 import static org.zwobble.precisely.AssertThat.assertThat;
 import static org.zwobble.precisely.Matchers.equalTo;
@@ -31,4 +33,47 @@ public class TypeCheckerConstructedTypeTests {
             equalTo(new ConstructedNativeType(listTypeConstructor, List.of(int32Type)))
         ));
     }
+
+    @Test
+    public void whenThereAreTooFewArgsThenErrorIsThrown() {
+        var untyped = UntypedArb.constructedType(
+            UntypedArb.typeLevelReference("List"),
+            List.of()
+        );
+        var context = TypeCheckerContextArb.namespaceContext();
+        var listType = SimpleNativeType.builtin("List");
+        var listTypeConstructor = new TypeConstructor<>(List.of(new TypeParam("T")), listType);
+        context.declare("List", new TypeLevelValueType(listTypeConstructor), NullSource.INSTANCE);
+
+        var error = assertThrows(
+            WrongNumberOfTypeLevelArgsError.class,
+            () -> TypeChecker.typeCheckTypeLevelExpression(untyped, context)
+        );
+
+        assertThat(error.expectedArgCount(), equalTo(1));
+        assertThat(error.actualArgCount(), equalTo(0));
+    }
+
+    @Test
+    public void whenThereAreTooManyArgsThenErrorIsThrown() {
+        var untyped = UntypedArb.constructedType(
+            UntypedArb.typeLevelReference("List"),
+            List.of(
+                UntypedArb.typeLevelReference("Int32"),
+                UntypedArb.typeLevelReference("Int64")
+            )
+        );
+        var context = TypeCheckerContextArb.namespaceContext();
+        var listType = SimpleNativeType.builtin("List");
+        var listTypeConstructor = new TypeConstructor<>(List.of(new TypeParam("T")), listType);
+        context.declare("List", new TypeLevelValueType(listTypeConstructor), NullSource.INSTANCE);
+
+        var error = assertThrows(
+            WrongNumberOfTypeLevelArgsError.class,
+            () -> TypeChecker.typeCheckTypeLevelExpression(untyped, context)
+        );
+
+        assertThat(error.expectedArgCount(), equalTo(1));
+        assertThat(error.actualArgCount(), equalTo(2));
+    }
 }