From 08d1cc0d7a12e5595d34933b982f73dc522232ff Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 19 Jun 2026 17:20:07 +0100
Subject: Throw better error on unknown namespace

---
 .../org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java     |  5 +++--
 .../hobgoblin/compiler/typechecker/UnknownNamespaceError.java | 11 +++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 src/main/java/org/zwobble/hobgoblin/compiler/typechecker/UnknownNamespaceError.java

(limited to 'src/main/java/org')

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java b/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java
index a8d8dee..9dba876 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java
@@ -7,6 +7,7 @@ import org.zwobble.hobgoblin.compiler.config.ProjectConfig;
 import org.zwobble.hobgoblin.compiler.parser.Parser;
 import org.zwobble.hobgoblin.compiler.typechecker.TypeChecker;
 import org.zwobble.hobgoblin.compiler.typechecker.TypeCheckerGlobalContext;
+import org.zwobble.hobgoblin.compiler.typechecker.UnknownNamespaceError;
 import org.zwobble.hobgoblin.compiler.types.NamespaceName;
 import org.zwobble.sourcetext.SourceText;
 
@@ -87,8 +88,8 @@ public class HobgoblinCompiler {
                     );
                     if (!handledNamespaceNames.contains(importedNamespaceName)) {
                         unhandledDependencies.add(
-                            // TODO: better error
-                            Optional.ofNullable(namespaceNodesByName.get(importedNamespaceName)).orElseThrow()
+                            Optional.ofNullable(namespaceNodesByName.get(importedNamespaceName))
+                                .orElseThrow(() -> new UnknownNamespaceError(importedNamespaceName, importNode.source()))
                         );
                     }
                 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/UnknownNamespaceError.java b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/UnknownNamespaceError.java
new file mode 100644
index 0000000..fb06f3b
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/UnknownNamespaceError.java
@@ -0,0 +1,11 @@
+package org.zwobble.hobgoblin.compiler.typechecker;
+
+import org.zwobble.hobgoblin.compiler.errors.SourceError;
+import org.zwobble.hobgoblin.compiler.sources.Source;
+import org.zwobble.hobgoblin.compiler.types.NamespaceName;
+
+public class UnknownNamespaceError extends SourceError {
+    public UnknownNamespaceError(NamespaceName namespaceName, Source source) {
+        super("Unknown namespace: " + namespaceName, source);
+    }
+}
-- 
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