diff --git a/gc.c b/gc.c
index e8c9afd5e8..6f726b3ca2 100644
--- a/gc.c
+++ b/gc.c
@@ -11152,7 +11152,6 @@ static const rb_data_type_t weakmap_type = {
     0, 0, RUBY_TYPED_FREE_IMMEDIATELY
 };
 
-extern const struct st_hash_type rb_hashtype_ident;
 static VALUE wmap_finalize(RB_BLOCK_CALL_FUNC_ARGLIST(objid, self));
 
 static VALUE
@@ -11160,8 +11159,8 @@ wmap_allocate(VALUE klass)
 {
     struct weakmap *w;
     VALUE obj = TypedData_Make_Struct(klass, struct weakmap, &weakmap_type, w);
-    w->obj2wmap = st_init_table(&rb_hashtype_ident);
-    w->wmap2obj = st_init_table(&rb_hashtype_ident);
+    w->obj2wmap = rb_init_identtable();
+    w->wmap2obj = rb_init_identtable();
     w->final = rb_func_lambda_new(wmap_finalize, obj, 1, 1);
     return obj;
 }