diff --git a/internal/class.h b/internal/class.h
index 0ac8e7c875..3e5108a3bd 100644
--- a/internal/class.h
+++ b/internal/class.h
@@ -62,9 +62,6 @@ struct rb_classext_struct {
         } singleton_class;
     } as;
     const VALUE includer;
-#if !SHAPE_IN_BASIC_FLAGS
-    shape_id_t shape_id;
-#endif
     attr_index_t max_iv_count;
     unsigned char variation_count;
     bool permanent_classpath : 1;
diff --git a/shape.c b/shape.c
index 05e5d76f60..5694833bfa 100644
--- a/shape.c
+++ b/shape.c
@@ -69,13 +69,6 @@ rb_shape_get_parent(rb_shape_t * shape)
 }
 
 #if !SHAPE_IN_BASIC_FLAGS
-shape_id_t
-rb_rclass_shape_id(VALUE obj)
-{
-    RUBY_ASSERT(RB_TYPE_P(obj, T_CLASS) || RB_TYPE_P(obj, T_MODULE));
-    return RCLASS_EXT(obj)->shape_id;
-}
-
 shape_id_t rb_generic_shape_id(VALUE obj);
 #endif
 
diff --git a/shape.h b/shape.h
index dc4a3d5ce1..025dfb4dd8 100644
--- a/shape.h
+++ b/shape.h
@@ -77,16 +77,15 @@ rb_current_shape_tree(void)
 }
 #define GET_SHAPE_TREE() rb_current_shape_tree()
 
-#if SHAPE_IN_BASIC_FLAGS
 static inline shape_id_t
-RBASIC_SHAPE_ID(VALUE obj)
+get_shape_id_from_flags(VALUE obj)
 {
     RUBY_ASSERT(!RB_SPECIAL_CONST_P(obj));
     return (shape_id_t)(SHAPE_MASK & ((RBASIC(obj)->flags) >> SHAPE_FLAG_SHIFT));
 }
 
 static inline void
-RBASIC_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
+set_shape_id_in_flags(VALUE obj, shape_id_t shape_id)
 {
     // Ractors are occupying the upper 32 bits of flags, but only in debug mode
     // Object shapes are occupying top bits
@@ -94,52 +93,49 @@ RBASIC_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
     RBASIC(obj)->flags |= ((VALUE)(shape_id) << SHAPE_FLAG_SHIFT);
 }
 
+
+#if SHAPE_IN_BASIC_FLAGS
+static inline shape_id_t
+RBASIC_SHAPE_ID(VALUE obj)
+{
+    return get_shape_id_from_flags(obj);
+}
+
+static inline void
+RBASIC_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
+{
+    set_shape_id_in_flags(obj, shape_id);
+}
+#endif
+
 static inline shape_id_t
 ROBJECT_SHAPE_ID(VALUE obj)
 {
     RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
-    return RBASIC_SHAPE_ID(obj);
+    return get_shape_id_from_flags(obj);
 }
 
 static inline void
 ROBJECT_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
 {
     RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
-    RBASIC_SET_SHAPE_ID(obj, shape_id);
+    set_shape_id_in_flags(obj, shape_id);
 }
 
 static inline shape_id_t
 RCLASS_SHAPE_ID(VALUE obj)
 {
     RUBY_ASSERT(RB_TYPE_P(obj, T_CLASS) || RB_TYPE_P(obj, T_MODULE));
-    return RBASIC_SHAPE_ID(obj);
-}
-
-#else
-
-static inline shape_id_t
-ROBJECT_SHAPE_ID(VALUE obj)
-{
-    RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
-    return (shape_id_t)(SHAPE_MASK & (RBASIC(obj)->flags >> SHAPE_FLAG_SHIFT));
+    return get_shape_id_from_flags(obj);
 }
 
 static inline void
-ROBJECT_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
+RCLASS_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
 {
-    RBASIC(obj)->flags &= SHAPE_FLAG_MASK;
-    RBASIC(obj)->flags |= ((VALUE)(shape_id) << SHAPE_FLAG_SHIFT);
+    RUBY_ASSERT(RB_TYPE_P(obj, T_CLASS) || RB_TYPE_P(obj, T_MODULE));
+    set_shape_id_in_flags(obj, shape_id);
 }
 
-shape_id_t rb_rclass_shape_id(VALUE obj);
-
-static inline shape_id_t RCLASS_SHAPE_ID(VALUE obj)
-{
-    return rb_rclass_shape_id(obj);
-}
-
-#endif
-
 rb_shape_t * rb_shape_get_root_shape(void);
 int32_t rb_shape_id_offset(void);
 
diff --git a/variable.c b/variable.c
index 90fa8760a0..39568db24a 100644
--- a/variable.c
+++ b/variable.c
@@ -1527,7 +1527,7 @@ rb_shape_set_shape_id(VALUE obj, shape_id_t shape_id)
         break;
       case T_CLASS:
       case T_MODULE:
-        RCLASS_EXT(obj)->shape_id = shape_id;
+        RCLASS_SET_SHAPE_ID(obj, shape_id);
         break;
       default:
         if (shape_id != SPECIAL_CONST_SHAPE_ID) {