diff --git a/AK/SourceGenerator.h b/AK/SourceGenerator.h
index 9c8c4b1155..a97e27e1c1 100644
--- a/AK/SourceGenerator.h
+++ b/AK/SourceGenerator.h
@@ -36,7 +36,15 @@ public:
     SourceGenerator fork() { return SourceGenerator { m_builder, m_mapping, m_opening, m_closing }; }
 
     void set(StringView key, String value) { m_mapping.set(key, value); }
-    String get(StringView key) const { return m_mapping.get(key).value(); }
+    String get(StringView key) const
+    {
+        auto result = m_mapping.get(key);
+        if (!result.has_value()) {
+            warnln("No key named `{}` set on SourceGenerator", key);
+            VERIFY_NOT_REACHED();
+        }
+        return result.release_value();
+    }
 
     StringView as_string_view() const { return m_builder.string_view(); }
     String as_string() const { return m_builder.build(); }