From 64dc722b28d34a153751a623a7f4f2e48a13655f Mon Sep 17 00:00:00 2001
From: Brian Smith <brian@dbsoft.org>
Date: Fri, 6 Mar 2026 23:47:55 -0600
Subject: [PATCH] Issue #2304 - Part 2 - Prerequisite: Teach GCPolicy about
 Maybe. https://bugzilla.mozilla.org/show_bug.cgi?id=1377008

---
 js/public/GCPolicyAPI.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/js/public/GCPolicyAPI.h b/js/public/GCPolicyAPI.h
index cffaee7140..0649c23265 100644
--- a/js/public/GCPolicyAPI.h
+++ b/js/public/GCPolicyAPI.h
@@ -39,6 +39,7 @@
 #ifndef GCPolicyAPI_h
 #define GCPolicyAPI_h
 
+#include "mozilla/Maybe.h"
 #include "mozilla/UniquePtr.h"
 
 #include "js/TraceKind.h"
@@ -160,6 +161,23 @@ struct GCPolicy<mozilla::UniquePtr<T, D>>
     }
 };
 
+// GCPolicy<Maybe<T>> forwards tracing/sweeping to GCPolicy<T*> if
+// when the Maybe<T> is full.
+template <typename T>
+struct GCPolicy<mozilla::Maybe<T>>
+{
+    static mozilla::Maybe<T> initial() { return mozilla::Maybe<T>(); }
+    static void trace(JSTracer* trc, mozilla::Maybe<T>* tp, const char* name) {
+        if (tp->isSome())
+            GCPolicy<T>::trace(trc, tp->ptr(), name);
+    }
+    static bool needsSweep(mozilla::Maybe<T>* tp) {
+        if (tp->isSome())
+            return GCPolicy<T>::needsSweep(tp->ptr());
+        return false;
+    }
+};
+
 } // namespace JS
 
 #endif // GCPolicyAPI_h