On Fri, Feb 8, 2019 at 2:35 PM Matthew Woehlke <mwoehlke.floss@gmail.com> wrote:

I could possibly quibble with whether that's "accurate", but I think
it's moot. Either this comes from the build system, or the user provides
it by hand (or something else?). In whichever case, I don't see why
providing the information for module dependencies would be any more
difficult than providing the comparable info for includes. IOW, we
aren't making this any harder than today.

I just want to make sure. This is true for _clang_ modules. Merged and TS modules introduces an indirection that makes finding module dependencies harder than just asking the compiler for includes. If the module does not exist yet, the compiler may be unable to answer that question. This leads to the module-mapper which provides the answer by magic.