diff --git a/shape.c b/shape.c
index 5b5e2ce4ec5c77..ee1cb5b4cf7567 100644
--- a/shape.c
+++ b/shape.c
@@ -30,7 +30,7 @@
 #define SINGLE_CHILD_P(x) ((uintptr_t)(x) & SINGLE_CHILD_TAG)
 #define SINGLE_CHILD(x) (rb_shape_t *)((uintptr_t)(x) & SINGLE_CHILD_MASK)
 #define ANCESTOR_CACHE_THRESHOLD 10
-#define MAX_SHAPE_ID (SHAPE_BUFFER_SIZE - 1)
+#define MAX_SHAPE_ID (INVALID_SHAPE_ID - 1)
 #define ANCESTOR_SEARCH_MAX_DEPTH 2
 
 static ID id_object_id;
diff --git a/shape.h b/shape.h
index c284cfb3a89945..b066bf3a15e05a 100644
--- a/shape.h
+++ b/shape.h
@@ -70,7 +70,7 @@ typedef uint32_t redblack_id_t;
 
 #define SHAPE_MAX_VARIATIONS 8
 
-#define INVALID_SHAPE_ID ((shape_id_t)-1)
+#define INVALID_SHAPE_ID (SHAPE_BUFFER_SIZE - 1)
 #define ATTR_INDEX_NOT_SET ((attr_index_t)-1)
 
 #define ROOT_SHAPE_ID                   0x0
@@ -187,8 +187,9 @@ RSHAPE_OFFSET(shape_id_t shape_id)
 static inline rb_shape_t *
 RSHAPE(shape_id_t shape_id)
 {
-    RUBY_ASSERT(shape_id != INVALID_SHAPE_ID);
-    return &rb_shape_tree.shape_list[RSHAPE_OFFSET(shape_id)];
+    shape_id_t offset = RSHAPE_OFFSET(shape_id);
+    RUBY_ASSERT(offset != INVALID_SHAPE_ID);
+    return &rb_shape_tree.shape_list[offset];
 }
 
 int32_t rb_shape_id_offset(void);
diff --git a/zjit/src/cruby_bindings.inc.rs b/zjit/src/cruby_bindings.inc.rs
index bd6a4afa25aa6f..1474551b5d2a41 100644
--- a/zjit/src/cruby_bindings.inc.rs
+++ b/zjit/src/cruby_bindings.inc.rs
@@ -1934,7 +1934,7 @@ pub const RUBY_OFFSET_EC_INTERRUPT_MASK: jit_bindgen_constants = 36;
 pub const RUBY_OFFSET_EC_THREAD_PTR: jit_bindgen_constants = 48;
 pub const RUBY_OFFSET_EC_RACTOR_ID: jit_bindgen_constants = 64;
 pub type jit_bindgen_constants = u32;
-pub const rb_invalid_shape_id: shape_id_t = 4294967295;
+pub const rb_invalid_shape_id: shape_id_t = 524287;
 pub type rb_iseq_param_keyword_struct =
     rb_iseq_constant_body_rb_iseq_parameters_rb_iseq_param_keyword;
 #[repr(C)]