"if condition is always false [redundant-expr]" false positive when variable set in a loop after the conditional #14993

Bug Report

The redundant-expr gives a false positive if you conditionally read a variable for another conditional inside a loop.

To Reproduce

def mypytest() -> int | None:
    trigger_segment = None
    violations = None
    for segment in [1, 2]:
        if segment == 2:
            violations = trigger_segment if trigger_segment else segment
        trigger_segment = segment
    return violations

The rule will trigger with error: If condition is always false [redundant-expr] on the if trigger_segment part of the ternary.

Expected Behavior

Mypy should not report anything because clearly the if condition is not always false: running print(mypytest()) will print 1.

Actual Behavior

The rule will trigger with error: If condition is always false [redundant-expr] on the if trigger_segment part of the ternary.

Your Environment

My configuration:

[tool.mypy]
plugins = [
    "pydantic.mypy"
]
files = "src/**/*.py,tests/**/*.py"
strict = true
# These are additional checks not covered by strict:
disallow_any_unimported = true
enable_error_code = """\
    ignore-without-code,\
    truthy-bool,\
    truthy-iterable,\
    redundant-expr,\
    redundant-self,\
    unused-awaitable\
    """
warn_unreachable = true

mypy 1.1.1 (compiled: yes)
% python --version
Python 3.11.1