Since PEP-560 was approved,
The following syntax has become available.

from queue import Queue
v = Queue[int]

It's a very shiny feature.
Given the direction of programming language, it's probably a very useful feature that users will use very often in the near future.

When I looked at Object/geneticiasobject.c, the current implementation is a very good condition for using the vectorcall proposed by PEP-590 .

The benchmarks are as follows.
So I suggest using vectorcall in GenericAlias.

if the suggestion is accepted, I 'd like to summit the patch :)

+--------------------+----------------------+-----------------------------+
| Benchmark | master-generic-alias | proposed-generic-alias |
+====================+======================+=============================+
| bench GenericAlias | 143 ns | 111 ns: 1.29x faster (-22%) |
+--------------------+----------------------+-----------------------------+

if the suggestion is accepted, I 'd like to summit the patch :)

Can you propose a PR, so I can have a look at the implementation?

Can you propose a PR, so I can have a look at the implementation?

Got it :), I will upload it soon.

I have doubts that GenericAlias instances are created in mass in tight loops. Do you have any realistic example which would benefit from speeding up creation of GenericAlias instances?

Do you have any realistic example which would benefit from speeding up the creation of GenericAlias instances?

Hmm I did not find loop tightly calling case, but
for example, this kinds of usage are very often.

def create_q(l: list[int]) -> Queue[int]:
    q = Queue[int]()
    for e in l:
        q.put(e)
    return q

a = create_q([1,2,3,4,5])

In this code, GenericAlias is called 2 times for function declare and function call.

It's true that GenericAlias ​​has a small portion in this scenario,
but wouldn't it be worth it if we could optimize itself to a few lines of code?

And how much faster has your example become?

And how much faster has your example become?

For function declaration, 5% enhancement,
the function call does not show difference because the GenericAlias is not big portion on calling.

+--------------------+------------------------+----------------------------+
| Benchmark | master-generic-alias-1 | bpo-40369-generic-alias-1 |
+====================+========================+============================+
| bench GenericAlias | 420 ns | 399 ns: 1.05x faster (-5%) |
+--------------------+------------------------+----------------------------+

Just for the record,

#19677 (comment)

guido left an opinion that the caching approach might be more proper.
So I 'd like to suggest open a new issue for caching. :)