Compilation error triggers segmentation fault

[strongoier]

A compilation error in a simple Taichi kernel triggers segmentation fault.

For the following script,

@ti.kernel
def foo():
    a

Expected result:

Traceback (most recent call last):
  File "test_slice.py", line 16, in <module>
    foo1()
  File "/home/xuyi15/taichi/python/taichi/lang/kernel_impl.py", line 932, in wrapped
    raise type(e)('\n' + str(e)) from None
taichi.lang.exception.TaichiNameError: 
File "test_slice.py", line 14, in foo1:
    a
    ^
Name "a" is not defined

Result on my environment (clang-8++):

free(): double free detected in tcache 2
Segmentation fault (core dumped)

The problem appears after #6335. Changing the compiler from clang-8++ to clang-10++ or clang-12++ solves the problem.

[strongoier]

#6363 provides a temporary fix but the root cause hasn't been understood yet.

[strongoier]

I'll close this issue for now as the fix has been merged. Feel free to reopen this if other issues related to this appear.