Incorrect type inference in loops

[Molkree]

Environment data

• Language Server version: v2022.3.4 - v2022.4.0
• OS and version: Win10
• Python version (& distribution if applicable, e.g. Anaconda): Python 3.10

Expected behaviour

No error.

Actual behaviour

Type of "high" is partially unknown
  Type of "high" is "int | Unknown"

Code Snippet / Additional information

def find_min(nums: list[int]) -> int:
    low = 0
    high = len(nums) - 1
    while low < high:
        mid = (low + high) // 2
        if nums[mid] > nums[high]:
            low = mid + 1
        elif nums[mid] < nums[high]:
            high = mid
        else:
            high -= 1  # <- error here
    return nums[low]

This might have the same root issue as the #2549 as it is also in a loop but this issue is present since v2020.3.4 and another one only since v2020.4.0 so I have opted to open a new ticket.

[erictraut]

Thanks for the bug report. This will be addressed in the next release. I've added a new unit test based on your code sample to help prevent future regression.

[heejaechang]

This issue has been fixed in version 2022.4.1, which we've just released. You can find the changelog here: CHANGELOG.md