René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Improve test cases for type substitution of a list of types after initial ParamSpec substitution","articleBody":"After merging https://github.com/python/cpython/pull/102808 I realized that I've missed several important cases.\r\n\r\nRight now substitution algorithm has these lines: https://github.com/python/cpython/blob/2cdc5189a6bc3157fddd814662bde99ecfd77529/Lib/typing.py#L1477-L1488\r\n\r\nIt is tested. But, it is never tested for the nested arguments:\r\n\r\nhttps://github.com/python/cpython/blob/2cdc5189a6bc3157fddd814662bde99ecfd77529/Lib/typing.py#L1500-L1511\r\n\r\nI think that `Callable` is complex and important enought to be covered with as many cases as possible. Furthermore, `Callable` can be nested deeply in real types and we need to be sure that this use-case works as intended.\r\n\r\nI will send a PR with more tests :)\r\n\r\nRelated https://github.com/python/cpython/issues/88965\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-103055\n* gh-103105\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/sobolevn","@type":"Person","name":"sobolevn"},"datePublished":"2023-03-27T08:12:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/103054/cpython/issues/103054"}