From a57746d5758dfd26a138a3837d42884571127d6c Mon Sep 17 00:00:00 2001
From: Peter Zhu <peter@peterzhu.ca>
Date: Mon, 18 May 2026 20:22:01 -0400
Subject: [PATCH 1/2] Fix compiler warnings for noreturn

    gc/mmtk/mmtk.c:480:1: warning: function 'rb_mmtk_gc_thread_bug' could be declared with attribute 'noreturn' [-Wmissing-noreturn]
      480 | {
          | ^
    gc/mmtk/mmtk.c:510:1: warning: function 'rb_mmtk_mutator_thread_panic_handler' could be declared with attribute 'noreturn' [-Wmissing-noreturn]
      510 | {
          | ^
---
 gc/mmtk/mmtk.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gc/mmtk/mmtk.c b/gc/mmtk/mmtk.c
index 24f0567..96e9e32 100644
--- a/gc/mmtk/mmtk.c
+++ b/gc/mmtk/mmtk.c
@@ -475,6 +475,7 @@ rb_mmtk_special_const_p(MMTk_ObjectReference object)
 }
 
 RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 1, 2)
+RBIMPL_ATTR_NORETURN()
 static void
 rb_mmtk_gc_thread_bug(const char *msg, ...)
 {
@@ -505,6 +506,7 @@ rb_mmtk_gc_thread_panic_handler(void)
     rb_mmtk_gc_thread_bug("MMTk GC thread panicked");
 }
 
+RBIMPL_ATTR_NORETURN()
 static void
 rb_mmtk_mutator_thread_panic_handler(void)
 {

From 76f510b94b1ba35232969f85bc80dfb42071d094 Mon Sep 17 00:00:00 2001
From: Peter Zhu <peter@peterzhu.ca>
Date: Tue, 19 May 2026 20:02:51 -0400
Subject: [PATCH 2/2] Sync gc.h

---
 gc/gc.h | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/gc/gc.h b/gc/gc.h
index 05f7e87..69e0e0b 100644
--- a/gc/gc.h
+++ b/gc/gc.h
@@ -194,6 +194,14 @@ gc_mark_tbl_no_pin_i(st_data_t key, st_data_t value, st_data_t data)
     return ST_CONTINUE;
 }
 
+static int
+gc_mark_set_no_pin_i(st_data_t key, st_data_t value, st_data_t data)
+{
+    rb_gc_mark_movable((VALUE)key);
+
+    return ST_CONTINUE;
+}
+
 static int
 hash_foreach_replace(st_data_t key, st_data_t value, st_data_t argp, int error)
 {
@@ -232,6 +240,36 @@ gc_update_table_refs(st_table *tbl)
     }
 }
 
+static int
+rb_set_foreach_replace(st_data_t key, st_data_t value, st_data_t argp, int error)
+{
+    if (rb_gc_location((VALUE)key) != (VALUE)key) {
+        return ST_REPLACE;
+    }
+
+    return ST_CONTINUE;
+}
+
+static int
+rb_set_replace_ref(st_data_t *key, st_data_t *value, st_data_t argp, int existing)
+{
+    if (rb_gc_location((VALUE)*key) != (VALUE)*key) {
+        *key = rb_gc_location((VALUE)*key);
+    }
+
+    return ST_CONTINUE;
+}
+
+static void
+gc_update_set_refs(st_table *tbl)
+{
+    if (!tbl || tbl->num_entries == 0) return;
+
+    if (st_foreach_with_replace(tbl, rb_set_foreach_replace, rb_set_replace_ref, 0)) {
+        rb_raise(rb_eRuntimeError, "hash modified during iteration");
+    }
+}
+
 static inline size_t
 xmalloc2_size(const size_t count, const size_t elsize)
 {