Call Arity notes
This wiki page is about the Call Arity analysis and transformation, which eta-expands definitions if we know that it is always being called with a certain number of arguments. This looks at the uses of a function, which is different from the the code in CoreArity, which looks at the definition of a function.
This pages does not document Call Arity as implemented; that documentation should be found and maintained with the code, at source:compiler/GHC/Core/Opt/CallArity.hs.
This page used to discuss possible changes to the analysis, but these are implemented now ([cb8a63cb]), so I removed the obsolete notes from here.