The post mentions from_chars specifically, and the quote about the range is about that function. That means we need to ask the question whether NaN is "in the r

The post mentions from_chars specifically, and the quote about the range is about that function. That means we need to ask the question whether NaN is "in the range representable by the type of value" too. For most other functions I would agree with you as NaN would be called out as a special case, and we have a meaningful range for all non-NaN values, but for from_chars I do not think "semantically important ranges" gets us there.