[New-bugs-announce] [issue40621] Python crashes with new parser on invalid exception handlers

[Shantanu]

New submission from Shantanu <hauntsaninja at gmail.com>:

```
~/dev/cpython master λ ./python.exe --version --version                                           
Python 3.9.0a6+ (heads/master:a15c9b3a05, May 14 2020, 00:31:47) 
[Clang 11.0.0 (clang-1100.0.33.17)]



# should raise a syntax error, instead crashes
~/dev/cpython master λ cat test.py 
try:
    1 / 0
except Exception as a.b:
    pass
~/dev/cpython master λ ./python.exe test.py            
[1]    63986 bus error  ./python.exe test.py
~/dev/cpython master λ ./python.exe -Xoldparser test.py
  File "/Users/shantanu/dev/cpython/test.py", line 3
    except Exception as a.b:
                         ^
SyntaxError: invalid syntax



# should raise a syntax error, instead passes
~/dev/cpython master λ cat test2.py
try:
    1 / 0
except Exception as (a):
    pass
~/dev/cpython master λ ./python.exe test2.py
~/dev/cpython master λ ./python.exe -Xoldparser test2.py
  File "/Users/shantanu/dev/cpython/test2.py", line 3
    except Exception as (a):
                        ^
SyntaxError: invalid syntax



# should raise a syntax error, instead crashes
~/dev/cpython master λ cat test3.py
try:
    1 / 0
except Exception as a[0]:
    pass
~/dev/cpython master λ ./python.exe test3.py
[1]    64206 bus error  ./python.exe test3.py
~/dev/cpython master λ ./python.exe -Xoldparser test3.py
  File "/Users/shantanu/dev/cpython/test3.py", line 3
    except Exception as a[0]:
                         ^
SyntaxError: invalid syntax
```

The old grammar expects a NAME here, but the new grammar attempts to use a target (https://docs.python.org/3/reference/grammar.html). Seems like we should just go back to using NAME.

----------
messages: 368818
nosy: hauntsaninja
priority: normal
severity: normal
status: open
title: Python crashes with new parser on invalid exception handlers

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40621>
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