Git blame will show the commit and the date for each line. It’s easy to verify if the snippet has changed since the comment. i use Emacs and it’s builtin vc package that color code each block.

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AnimalMuppet 9 hours ago | parent [-]

But you need the snippet and, potentially, the entire call tree (both up and down).

	▲	dullcrisp 9 hours ago \| parent [-]
		And anything that can affect relevant state, any dependencies that may have changed, validations to input that may have been modified; it’s hard to know without knowing what assumptions the assertion is based on.