Alternative instances no longer require MonadPlus#106
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GregoryTravis wants to merge 6 commits intohaskell:mainfrom
Open
Alternative instances no longer require MonadPlus#106GregoryTravis wants to merge 6 commits intohaskell:mainfrom
GregoryTravis wants to merge 6 commits intohaskell:mainfrom
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sjshuck
reviewed
Feb 7, 2026
Control/Monad/Trans/RWS/CPS.hs
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| instance (Functor m, MonadPlus m) => Alternative (RWST r w s m) where | ||
| empty = RWST $ \ _ _ _ -> mzero | ||
| instance (Functor m, Alternative m, Monad m) => Alternative (RWST r w s m) where |
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There are some redundant constraints here.
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I removed Functor here; Monad seems to need to stay because of the do block in Applicative RWST.
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Fixes #83 by requiring
Alternativerather thanMonadPlusin theAlternativeinstances for: