From ad3e527a337ba2c02eac1aafdc17124c76cc1b92 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Thu, 25 Jun 2026 18:17:19 +0100
Subject: Throw better error when value is not type

---
 .../compiler/ast/untyped/UntypedTypeLevelExpressionNode.java     | 2 ++
 .../org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java  | 9 ++++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/ast/untyped/UntypedTypeLevelExpressionNode.java b/src/main/java/org/zwobble/hobgoblin/compiler/ast/untyped/UntypedTypeLevelExpressionNode.java
index b5dbd5d..532d8de 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/ast/untyped/UntypedTypeLevelExpressionNode.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/ast/untyped/UntypedTypeLevelExpressionNode.java
@@ -10,6 +10,8 @@ public sealed interface UntypedTypeLevelExpressionNode permits org.zwobble.hobgo
         // Custom area end: org.zwobble.hobgoblin.compiler.ast.untyped.UntypedTypeLevelExpressionNode.Builder body
     }
 
+    public org.zwobble.hobgoblin.compiler.sources.Source source();
+
     // Custom area start: org.zwobble.hobgoblin.compiler.ast.untyped.UntypedTypeLevelExpressionNode body
     // Custom area end: org.zwobble.hobgoblin.compiler.ast.untyped.UntypedTypeLevelExpressionNode body
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java
index 5003e3a..c291aaf 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java
@@ -258,7 +258,7 @@ public class TypeChecker {
         );
     }
 
-    private static TypedTypeLevelExpressionNode<Type> typeCheckMetaType(
+    static TypedTypeLevelExpressionNode<Type> typeCheckMetaType(
         UntypedTypeLevelExpressionNode untyped,
         TypeCheckerNamespaceContext context
     ) {
@@ -266,8 +266,11 @@ public class TypeChecker {
         if (typed.value() instanceof Type) {
             return (TypedTypeLevelExpressionNode<Type>) typed;
         } else {
-            // TODO: better error
-            throw new RuntimeException("not a metatype");
+            throw new UnexpectedTypeError(
+                new TypeSet.MetaType(),
+                new TypeLevelValueType(typed.value()),
+                untyped.source()
+            );
         }
     }
 
-- 
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