
Hi all, GHC HEAD currently suggests valid in-scope single-identifier substitutions for typed holes (underscores in terms). Some unrelated work somehow changed the output, and I'm wondering if this is a change for the better or for the worse. The test case is this:
f :: Int -> Int -> Int f x y = _ x y
With my patch, GHC now suggests `pure` and `return` as replacements for _ (along with the other top contenders of (-), asTypeOf, and const). (You can also increase the number of suggestions, which will then include (+) and (*) among others.) It's true that `pure` and `return` fit the bill, noting that ((->) Int) is an Applicative. But I doubt these suggestions will help the user. I'm not keen to make fixing this "valid suggestions" feature (which I do really like) a dependency of finishing my patch, but I also don't want the change to output to go unnoticed. So, I'm asking: when I merge my patch, should I post a bug asking for perhaps a priority ordering of suggestions? Thanks, Richard