[New-bugs-announce] [issue35992] Metaclasses interfere with __class_getitem__

[Caleb Donovick]

New submission from Caleb Donovick <donovick at cs.stanford.edu>:

OS:
Debian testing

python3 -VV:
Python 3.7.2+ (default, Feb  2 2019, 14:31:48)
[gcc 8.2.0]


The following:
```
class Meta(type): pass

class X(metaclass=Meta):
    def __class_getitem__(cls, key):
        return key

X[10]
```
Results in 
```
TypeError: 'Meta' object does not support indexing
```

However, PEP 560 specifically states that __class_getitem__ should be used as fall back for when a metaclass does not implement __getitem__.

----------
assignee: docs at python
components: Documentation, Interpreter Core
messages: 335497
nosy: Donovick, docs at python
priority: normal
severity: normal
status: open
title: Metaclasses interfere with __class_getitem__
type: behavior
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue35992>
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