On Wed, Mar 06, 2019 at 16:16:06 -0500, Steve Downey wrote:
> For an #include you can run the preprocessor exactly. For an import you, at
> least in theory, need either know how the bmi was created, or do the
> processing implicitly and then import the BMI. If I understand correctly,
> this is why clang will track the flags used in implicit bmi creation,
> because they might change and make the BMI incorrect.

That mismatch is an error for compile time. Scanning can assume the
`import` will succeed because if the assumption is invalid, it isn't
going to compile anyways and something will force the scan to happen
again whether it is command line changing or input file contents
changing.

--Ben