Description

serhiy-storchaka

opened on Aug 1, 2021

Issue body actions

BPO	44802
Nosy	@gvanrossum, @serhiy-storchaka, @Fidget-Spinner

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-08-01.11:37:51.360>
labels = ['type-bug', 'library', '3.10', '3.11']
title = 'Substitution does not work after ParamSpec substitution of the user generic with a list of TypeVars'
updated_at = <Date 2021-08-01.11:37:51.360>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2021-08-01.11:37:51.360>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-08-01.11:37:51.360>
creator = 'serhiy.storchaka'
dependencies = []
files = []
hgrepos = []
issue_num = 44802
keywords = []
message_count = 1.0
messages = ['398694']
nosy_count = 3.0
nosy_names = ['gvanrossum', 'serhiy.storchaka', 'kj']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue44802'
versions = ['Python 3.10', 'Python 3.11']

Linked PRs

• gh-88965: Fix type substitution of a list of types after initial ParamSpec substitution #102808
• [3.11] gh-88965: typing: fix type substitution of a list of types after initial ParamSpec substitution (GH-102808) #102957

Activity

1. serhiy-storchaka commented on Aug 1, 2021

   

   serhiy-storchaka

   on Aug 1, 2021

   MemberAuthor

   More actions

   If the user generic with ParamSpec parameter substituted with a parametrised list containing TypeVar, that TypeVar cannot be substituted.

   >>> from typing import *
   >>> T = TypeVar("T")
   >>> P = ParamSpec("P")
   >>> class X(Generic[P]):
   ...     f: Callable[P, int]
   ... 
   >>> Y = X[[int, T]]
   >>> Y
   __main__.X[(<class 'int'>, ~T)]
   >>> Y[str]
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "/home/serhiy/py/cpython/Lib/typing.py", line 309, in inner
       return func(*args, **kwds)
              ^^^^^^^^^^^^^^^^^^^
     File "/home/serhiy/py/cpython/Lib/typing.py", line 1028, in __getitem__
       _check_generic(self, params, len(self.__parameters__))
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     File "/home/serhiy/py/cpython/Lib/typing.py", line 228, in _check_generic
       raise TypeError(f"{cls} is not a generic class")
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   TypeError: __main__.X[(<class 'int'>, ~T)] is not a generic class

   Expected result equal to X[[int, str]].

   Reacted by LeeeeT
2. serhiy-storchaka

   added

   3.10 (EOL)end of lifeend of life

   3.11only security fixesonly security fixes

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Aug 1, 2021
3. ezio-melotti

   transferred this issue fromon Apr 10, 2022
4. AlexWaygood

   added

   topic-typing

   on Apr 13, 2022
5. LeeeeT commented on Nov 11, 2022

   

   LeeeeT

   on Nov 11, 2022

   More actions

   Hi there! I'm experiencing the same issue. Will this be fixed? @serhiy-storchaka
6. serhiy-storchaka

   self-assigned this

   on Nov 11, 2022
7. AlexWaygood

   added

   3.12only security fixesonly security fixes

   on Mar 15, 2023
8. sobolevn

   added a commit that references this issue on Mar 18, 2023

   pythongh-88965: Fix type substitution of a list of types after initia…

   55662cc
9. AlexWaygood

   added a commit that references this issue on Mar 23, 2023

   gh-88965: typing: fix type substitution of a list of types after init…

   adb0621
10. miss-islington

    added a commit that references this issue on Mar 23, 2023

    pythongh-88965: typing: fix type substitution of a list of types afte…

    3d006ac
11. AlexWaygood commented on Mar 23, 2023

    

    AlexWaygood

    on Mar 23, 2023

    Member

    More actions

    Fixed on main and 3.11, but we've decided not to backport to 3.10.
12. AlexWaygood

    closed this as completedon Mar 23, 2023
13. miss-islington

    added a commit that references this issue on Mar 23, 2023

    gh-88965: typing: fix type substitution of a list of types after init…

    1645a40
14. LeeeeT commented on Mar 23, 2023

    

    LeeeeT

    on Mar 23, 2023

    More actions

    Thanks! You guys are awesome! ❤️

    Reacted by Alex Waygood
15. AlexWaygood commented on Mar 23, 2023

    

    AlexWaygood

    on Mar 23, 2023

    Member

    More actions

    Thanks! You guys are awesome! ❤️

    @sobolevn gets all the credit on this one :)

    Reacted by LeeeeT
16. Fidget-Spinner

    added a commit that references this issue on Mar 27, 2023

    pythongh-88965: typing: fix type substitution of a list of types afte…

    67a48e5
17. warsaw

    added a commit that references this issue on Apr 11, 2023

    pythongh-88965: typing: fix type substitution of a list of types afte…

    a6097ae

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