[issue33677] Fix signatures of tp_clear handlers

[Serhiy Storchaka]

New submission from Serhiy Storchaka <storchaka+cpython at gmail.com>:

The tp_clear handler should be a pointer to the function that returns int.

    typedef int (*inquiry)(PyObject *);

Two handlers in the stdlib (for AST and deque objects) return void instead. The following PR fixes this.

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components: Extension Modules
messages: 317986
nosy: rhettinger, serhiy.storchaka
priority: normal
severity: normal
status: open
title: Fix signatures of tp_clear handlers
type: behavior
versions: Python 2.7, Python 3.6, Python 3.7, Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue33677>
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