diff --git a/iseq.c b/iseq.c
index b3c7ad53d3..7fbb906525 100644
--- a/iseq.c
+++ b/iseq.c
@@ -427,14 +427,11 @@ rb_iseq_memsize(const rb_iseq_t *iseq)
     return size;
 }
 
-static unsigned long fresh_iseq_unique_id = 0; /* -- Remove In 3.0 -- */
-
 static rb_iseq_t *
 iseq_alloc(void)
 {
     rb_iseq_t *iseq = iseq_imemo_alloc();
     iseq->body = ZALLOC(struct rb_iseq_constant_body);
-    iseq->body->iseq_unique_id = fresh_iseq_unique_id++; /* -- Remove In 3.0 -- */
     return iseq;
 }
 
diff --git a/vm_args.c b/vm_args.c
index 41824527de..97b1d4ac60 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -593,12 +593,8 @@ VALUE rb_iseq_location(const rb_iseq_t *iseq);
  */
 static st_table *caller_to_callees = 0;
 
-static VALUE rb_warn_check(const rb_execution_context_t * const ec, const rb_iseq_t *const iseq)
+static VALUE rb_warn_check(const rb_execution_context_t * const ec, const void *const callee)
 {
-    if (!iseq) return 0;
-
-    const void *const callee = (void *)iseq->body->iseq_unique_id;
-
     const rb_control_frame_t * const cfp = rb_vm_get_ruby_level_next_cfp(ec, ec->cfp);
 
     if (!cfp) return 0;
diff --git a/vm_core.h b/vm_core.h
index 4b1b9e43d0..f7ec156cc5 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -447,8 +447,6 @@ struct rb_iseq_constant_body {
     long unsigned total_calls; /* number of total calls with `mjit_exec()` */
     struct rb_mjit_unit *jit_unit;
 #endif
-
-    unsigned long iseq_unique_id; /* -- Remove In 3.0 -- */
 };
 
 /* T_IMEMO/iseq */