If I do: ghc -o foo foo.hs and then immediately afterward: ghc -fext-core -c foo.hs

and foo.hcr doesn't exist, ghc still says "Compilation is not required" and doesn't create the External Core file. It should generate the .hcr given the -fext-core flag, even if the .hi file is up to date.

Sorry if this is a duplicate bug (I know that making the compilation manager pay attention to flags is an ongoing issue).