Currently, music-score defines orphan Num instances for Sum and Product. However, there is at least one other package that exports these same orphan instances (Agda), possibly others. If these packages were used together on an old version of GHC, it could lead to instance conflicts.
To help mitigate this possibility, this pull request imports these instances from the base-orphans library (which exports backported instances introduced in later versions of base, including the aforementioned ones). This way, we can keep all of these orphan instances in one package so that Agda, music-score, etc. can coexist.
Currently,
music-scoredefines orphanNuminstances forSumandProduct. However, there is at least one other package that exports these same orphan instances (Agda), possibly others. If these packages were used together on an old version of GHC, it could lead to instance conflicts.To help mitigate this possibility, this pull request imports these instances from the
base-orphanslibrary (which exports backported instances introduced in later versions ofbase, including the aforementioned ones). This way, we can keep all of these orphan instances in one package so thatAgda,music-score, etc. can coexist.