Re: [Haskell-cafe] Haskell interface files: Why used? What about same data in object files?

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for some changes of .hs file (where just the implementation changes) the .o file can be regenerated without touching the .hi file. This allows more accurate build dependencies and less recompilation.

Is that really the case? I thought that GHC may add code to the interface files for cross-module inlining purposes, which means that changing the implementation might change the interface too.

Indeed, GHC _may_ change the interface file for such reasons, but it may equally decide to leave the interface untouched, e.g. if there are no new inlinings. Regards, Malcolm