Proposed warning: reuse of loop variable in nested loop

I was just bitten by a bug in production where I accidentally reused an outer loop variable in a nested loop. Example:

# Outer loop.
for i in range(10):
    # Enough code here to hide the outermost loop off screen.
    # ...

    # Developer does not notice "i" is already being used as a loop variable
    # and accidentally overwrites it here. The type is the same, so type checkers
    # don't complain.
    for i in range(10):
        print(f"inner loop {i=}")

    # Enough code here to hide the innermost loop off screen.
    # ...

    # Developer expects "i" to still hold the value of the outer loop.
    # Instead, the value is always 9.
    print(f"outer loop {i=}")

Proposed warning: B???: "Variable 'i' is already declared in 'for' loop or 'with' statement above"

Credit for the wording: this is one of PyCharm's built-in inspections.

No files, tests, or entry points are named. Start by tracing how existing flake8-bugbear warnings detect loop and with-statement variables, then identify the relevant test location and add coverage for the nested-loop example; done means the proposed warning is emitted for accidental reuse without flagging valid cases.