diff --git a/shape.c b/shape.c
index 13d1edf36c..90036722f1 100644
--- a/shape.c
+++ b/shape.c
@@ -950,12 +950,10 @@ rb_shape_transition_add_ivar(VALUE obj, ID id)
 }
 
 shape_id_t
-rb_shape_transition_add_ivar_no_warnings(VALUE obj, ID id)
+rb_shape_transition_add_ivar_no_warnings(VALUE klass, shape_id_t original_shape_id, ID id)
 {
-    shape_id_t original_shape_id = RBASIC_SHAPE_ID(obj);
     RUBY_ASSERT(!shape_frozen_p(original_shape_id));
 
-    VALUE klass = obj_get_owner_class(obj);
     rb_shape_t *next_shape = shape_get_next(RSHAPE(original_shape_id), SHAPE_IVAR, klass, id, false);
     if (next_shape) {
         return shape_id(next_shape, original_shape_id);
diff --git a/shape.h b/shape.h
index 28c2a7eef9..bebfaba608 100644
--- a/shape.h
+++ b/shape.h
@@ -230,7 +230,7 @@ shape_id_t rb_shape_transition_frozen(VALUE obj);
 shape_id_t rb_shape_transition_complex(VALUE obj);
 shape_id_t rb_shape_transition_remove_ivar(VALUE obj, ID id, shape_id_t *removed_shape_id);
 shape_id_t rb_shape_transition_add_ivar(VALUE obj, ID id);
-shape_id_t rb_shape_transition_add_ivar_no_warnings(VALUE obj, ID id);
+shape_id_t rb_shape_transition_add_ivar_no_warnings(VALUE klass, shape_id_t original_shape_id, ID id);
 shape_id_t rb_shape_transition_object_id(VALUE obj);
 shape_id_t rb_shape_transition_heap(VALUE obj, size_t heap_index);
 shape_id_t rb_shape_object_id(shape_id_t original_shape_id);
diff --git a/yjit/src/codegen.rs b/yjit/src/codegen.rs
index 50762c64d3..865f80ca4f 100644
--- a/yjit/src/codegen.rs
+++ b/yjit/src/codegen.rs
@@ -3101,7 +3101,9 @@ fn gen_set_ivar(
     let mut new_shape_too_complex = false;
     let new_shape = if !shape_too_complex && receiver_t_object && ivar_index.is_none() {
         let current_shape_id = comptime_receiver.shape_id_of();
-        let next_shape_id = unsafe { rb_shape_transition_add_ivar_no_warnings(comptime_receiver, ivar_name) };
+        // We don't need to check about imemo_fields here because we're definitely looking at a T_OBJECT.
+        let klass = unsafe { rb_obj_class(comptime_receiver) };
+        let next_shape_id = unsafe { rb_shape_transition_add_ivar_no_warnings(klass, current_shape_id, ivar_name) };
 
         // If the VM ran out of shapes, or this class generated too many leaf,
         // it may be de-optimized into OBJ_TOO_COMPLEX_SHAPE (hash-table).
diff --git a/yjit/src/cruby_bindings.inc.rs b/yjit/src/cruby_bindings.inc.rs
index 6efef9c55c..b9a8197184 100644
--- a/yjit/src/cruby_bindings.inc.rs
+++ b/yjit/src/cruby_bindings.inc.rs
@@ -1064,7 +1064,11 @@ extern "C" {
     pub fn rb_shape_id_offset() -> i32;
     pub fn rb_obj_shape_id(obj: VALUE) -> shape_id_t;
     pub fn rb_shape_get_iv_index(shape_id: shape_id_t, id: ID, value: *mut attr_index_t) -> bool;
-    pub fn rb_shape_transition_add_ivar_no_warnings(obj: VALUE, id: ID) -> shape_id_t;
+    pub fn rb_shape_transition_add_ivar_no_warnings(
+        klass: VALUE,
+        original_shape_id: shape_id_t,
+        id: ID,
+    ) -> shape_id_t;
     pub fn rb_ivar_get_at(obj: VALUE, index: attr_index_t, id: ID) -> VALUE;
     pub fn rb_ivar_get_at_no_ractor_check(obj: VALUE, index: attr_index_t) -> VALUE;
     pub fn rb_gvar_get(arg1: ID) -> VALUE;
diff --git a/zjit/src/cruby_bindings.inc.rs b/zjit/src/cruby_bindings.inc.rs
index 7bd3925639..0048fd6dae 100644
--- a/zjit/src/cruby_bindings.inc.rs
+++ b/zjit/src/cruby_bindings.inc.rs
@@ -2033,7 +2033,11 @@ unsafe extern "C" {
     pub fn rb_shape_id_offset() -> i32;
     pub fn rb_obj_shape_id(obj: VALUE) -> shape_id_t;
     pub fn rb_shape_get_iv_index(shape_id: shape_id_t, id: ID, value: *mut attr_index_t) -> bool;
-    pub fn rb_shape_transition_add_ivar_no_warnings(obj: VALUE, id: ID) -> shape_id_t;
+    pub fn rb_shape_transition_add_ivar_no_warnings(
+        klass: VALUE,
+        original_shape_id: shape_id_t,
+        id: ID,
+    ) -> shape_id_t;
     pub fn rb_ivar_get_at_no_ractor_check(obj: VALUE, index: attr_index_t) -> VALUE;
     pub fn rb_gvar_get(arg1: ID) -> VALUE;
     pub fn rb_gvar_set(arg1: ID, arg2: VALUE) -> VALUE;