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Whoa, I never thought that would get fixed. It's been, what, 20 years? :-)

So why wasn't it done earlier? Is there going to be any code breakage with that?

I think Applicative was introduced within the last 10 years. The paper that introduced them was published in 2008 (Applicative Programming with Effects, Conor McBride and Ross Paterson)

That just drives home how long it's been the case that Applicative wasn't a superclass of Monad! ;)

What if you count the total length of time that monads have not been "officially" applicative functors?

There have been deprecation warnings (since 7.8?) about the AMP:

https://wiki.haskell.org/Functor-Applicative-Monad_Proposal#...

There's a list of breakage at:

https://www.fpcomplete.com/blog/2015/03/stackage-ghc-7-10

(I'm not sure what portion of that is due to AMP.)

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