My variant on this tends to go:

"It looks like this <code block/method/module> will cause XYZ to happen. Is that what you intended?"

Simple example (Python):

    def foo(x):
        print(x.lower())

"If x is None this will raise an exception. Is that an expected outcome, and/or can we assume x is always non-None?"

One thing I like about this approach is that it first describes your understanding of a particular code section, which helps illuminate any assumptions we might hold (and which might be incorrect). This is a good practice generally, IMHO, with or without the followup question. A guy I used to work with would make non-judgemental comments that just summarized his understanding of what was happening in the code, and it was helpful because when the comment was off, it illustrated a way in which the code was perhaps unclear or incorrect.