[bug] Fix potential bug in #6362 (#6363) (#6371)

Issue: #6362

Issue: #

### Brief Summary

Co-authored-by: Yi Xu <[email protected]>

Author: jim19930609

taichi/program/kernel.cpp

@@ -30,8 +30,9 @@ Kernel::Kernel(Program &program,
                const std::function<void(Kernel *)> &func,
                const std::string &primal_name,
                AutodiffMode autodiff_mode) {
+  // due to #6362, we cannot write [func, this] { return func(this); }
   this->init(
-      program, [func, this] { return func(this); }, primal_name, autodiff_mode);
+      program, [&] { return func(this); }, primal_name, autodiff_mode);
 }
 
 Kernel::Kernel(Program &program,