[Bug][阻塞] PTODSL's `for` loop incorrectly carries variables initialized inside `pto.vecscope()`

[liggest]

Component

PTODSL

Description

PTODSL 中，若 for ... in range(...) 循环中包含 pto.vecscope() 块，完全在 pto.vecscope() 内声明并读写的变量会被暴露到 for 循环中，成为循环内携带（carry）的变量

但由于变量只在 pto.vecscope() 块内创建，导致触发 UnboundLocalError，使得编译失败

Reproduction (minimal)

from ptodsl import pto


@pto.jit(kernel_kind="vector", target="a5", mode="explicit")
def kernel(n: pto.i32):
    for _ in range(0, n):
        with pto.vecscope():
            acc = pto.const(0, dtype=pto.i32)
            acc = acc + 1



print(kernel.compile().mlir_text())

Expected behavior

编译成功通过

Actual behavior / error logs

Traceback (most recent call last):
  File "ptodsl_for_vecscope.py", line 13, in <module>
    print(kernel.compile().mlir_text())
  File "ptodsl/ptodsl/_jit.py", line 290, in compile
    return self._compiler.compile(**constexpr_bindings)
  File "ptodsl/ptodsl/_kernel_compilation.py", line 138, in compile
    compiled.build()
  File "ptodsl/ptodsl/_tracing/artifacts.py", line 34, in build
    built = self._module_factory()
  File "ptodsl/ptodsl/_tracing/runtime.py", line 86, in build_module
    self.trace_entry(*args)
  File "ptodsl/ptodsl/_tracing/runtime.py", line 128, in trace_entry
    result = self._callback(*args, **kwargs)
  File "ptodsl_for_vecscope.py", line 3, in kernel
    
UnboundLocalError: local variable 'acc' referenced before assignment

Git commit

370e626

Host platform

Linux (x86_64)

Target Ascend arch (if relevant)

a5

PTOAS build level (if relevant)

None