Overall I am all for simplifying this stuff, but the bit where constraints
with no variables are not simplified seems quite confusing. More
concretely, using the example from the proposal:
bar :: forall a b. (a ~ Int) => a -> b -> a
Is it the case that `:t bar @Bool` will print
bar :: (Bool ~ Int) => Bool -> b -> Bool
This looks particularly confusing without the explicit `forall`, although
it seems questionable either way.
-Iavor
On Thu, Mar 14, 2019 at 7:47 AM Joachim Breitner
Dear Committee,
Richard, in collarboration with Simon PJ, proposes some tweaks to how foralls are printed by GHC.
In particular, whenever a type variable is printed with an forall, it is printed with {a} unless it is a specified variable. And there are tweaks to what :type does with its argument that makes it more useful, and obviates the need for a separate :type +v.
https://github.com/goldfirere/ghc-proposals/blob/printing-foralls/proposals/...
I like that it actually simplifies the UI (by removing :type +v), so I recommend acceptance.
Cheers, Joachim -- Joachim Breitner mail@joachim-breitner.de http://www.joachim-breitner.de/
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