Check that receiver of type-level args is type constructor

1 files changed, 22 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 c0a7f93..4f409d2 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerConstructedTypeTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerConstructedTypeTests.java
@@ -3,6 +3,7 @@ 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.UnexpectedTypeError;
 import org.zwobble.hobgoblin.compiler.typechecker.errors.WrongNumberOfTypeLevelArgsError;
 import org.zwobble.hobgoblin.compiler.types.*;
 
@@ -15,6 +16,27 @@ import static org.zwobble.precisely.Matchers.equalTo;
 
 public class TypeCheckerConstructedTypeTests {
     @Test
+    public void whenReceiverIsNotTypeConstructorThenErrorIsThrown() {
+        var untyped = UntypedArb.constructedType(
+            UntypedArb.typeLevelReference("List"),
+            List.of(UntypedArb.typeLevelReference("Int32"))
+        );
+        var context = TypeCheckerContextArb.namespaceContext();
+        var listType = SimpleNativeType.builtin("List");
+        context.declare("List", new TypeLevelValueType(listType), NullSource.INSTANCE);
+        var int32Type = SimpleNativeType.builtin("Int32");
+        context.declare("Int32", new TypeLevelValueType(int32Type), NullSource.INSTANCE);
+
+        var error = assertThrows(
+            UnexpectedTypeError.class,
+            () -> TypeChecker.typeCheckTypeLevelExpression(untyped, context)
+        );
+
+        assertThat(error.expected(), equalTo(new TypeSet.TypeConstructor()));
+        assertThat(error.actual(), equalTo(new TypeLevelValueType(listType)));
+    }
+
+    @Test
     public void whenArgsMatchParamsThenCanConstructTypeFromTypeConstructor() {
         var untyped = UntypedArb.constructedType(
             UntypedArb.typeLevelReference("List"),