Oleg Grenrus

I forgot to mention that it would be good that specification is not only revertible but also transitive: I can think of revision path like: ```cabal -- 1 build-depends: foo...

I cannot reproduce this on Ubuntu, I think this is `cpp-11` (clang, not gcc?) not working as the other variants, GCC doesn't seem to barf about `-traditional`. Which is weird,...

You could try whether ```bash touch foo.c ghc -optP -traditional -v3 -c -o foo.o foo.c # or/and ghc -pgmP cpp-11 -optP -traditional -v3 -c -o foo.o foo.c ``` works on...

I'm tempted to close this as "`fudgets.cabal`" is broken. Why they need to change c preprocessor and specify it to traditional? When compiling Haskell CPP is run in `-traditional` by...

Thinking a bit more: GHC ought should have different flags for Haskell CPP and C CPP. Now they are the same `pgmP` and `optP`. So I don't see how this...

I figured the problem. It's indeed GHC-8.8.4 (and later, 8.10, 9.0, 9.2) issue. ``` ghc-8.8.4 -optP -traditional -v3 -c -o foo.o foo.c ``` ``` *** C Compiler: gcc -DTABLES_NEXT_TO_CODE -x...

I mark this as high priority as 3.0 cannot be released before **Add a visibility field to sublibraries** is done. ping @23Skidoo @hvr

Should solver be able to flip flags based on `visible` field? I think it should, but I don't know if it will make implementation tricky. I don't know a good...

we will need `MIN_VERSION_pkgB:foo` kind of thing. No idea how the name should be generated though. Maybe double underscore: `MIN_VERSION_pkgB__foo`? as there cannot be package `pkgB--foo`?

Should visibility be recorded into `InstalledInfo`. Then `./Setup.hs` will be able to fail if you try to "manually" use a internal library which was registered as non-visible. Note: this change...