Re: Type-level generics

2017-09-01 Thread Oleg Grenrus
Seems that by making a class you can "prove" by requiring this isomorphism: class (To r ~ v, From v ~ r) -- , To (From v :: Rep a x) ~ v) => TypeGeneric a (r :: Rep a x) (v :: a) where type To r :: a type From v :: Rep a x See attachment or [1] for the whole

[broken HEAD] In which the strict state monad fails at basic arithmetic

2017-09-01 Thread Moritz Angermann
Hi *, while working on some related code. I came across a rather peculiar behavior with GHC built from the current master branch at b2c2e3e8. After condensing the application quite a bit[1], the test case now produces 8 with ghc 8.2.1 and -6 with ghc 8.3 @ b2c2e3e8 The sample application

Re: Type-level generics

2017-09-01 Thread Ryan Scott
While we're on the topic, I'll mention that at one point I attempted to modify the singletons [1] library so that it would automatically generate promoted (i.e., type-level) and singled versions of Generic instances for any data type that derived Generic. I wasn't successful, since it turns out

Re: [broken HEAD] In which the strict state monad fails at basic arithmetic

2017-09-01 Thread Ben Gamari
Moritz Angermann writes: > Hi *, > > while working on some related code. I came across a rather peculiar behavior > with GHC built from the current master branch at b2c2e3e8. > Indeed this sounds like a real bug. Can you open a ticket? Also, it looks like the gist

Re: [broken HEAD] In which the strict state monad fails at basic arithmetic

2017-09-01 Thread Ben Gamari
Moritz Angermann writes: > Hi *, > > while working on some related code. I came across a rather peculiar behavior > with GHC built from the current master branch at b2c2e3e8. > The issue was a bug indeed introduced by the commit you cite below. The problem was a

Re: Type-level generics

2017-09-01 Thread Wolfgang Jeltsch
Hi! Before starting with generics support at the type level, please first improve the generics support at the value level. When I looked at it the last time, there were some apparent leftovers in the form of types or type parameters never used. In addition, it seems awkward that you have to pass

RE: [broken HEAD] In which the strict state monad fails at basic arithmetic

2017-09-01 Thread Simon Peyton Jones via ghc-devs
Wow -- Fast work! Do add a test case Simon | -Original Message- | From: ghc-devs [mailto:ghc-devs-boun...@haskell.org] On Behalf Of Ben | Gamari | Sent: 01 September 2017 14:53 | To: Moritz Angermann ; GHC developers | Subject: Re: [broken HEAD] In which

Re: Convenient URL alias for Trac tickets

2017-09-01 Thread Ben Gamari
Herbert Valerio Riedel writes: > Good idea! > > ...btw, note that a couple years ago, I set up the little known > > http://ghc.haskell.org/ticket/1234 > > alias... :-) > Indeed I noticed that and it almost deterred me from adding the new alias. However, I am sympathetic

Re: Type-level generics

2017-09-01 Thread Evan Laforge
On Fri, Sep 1, 2017 at 2:23 PM, Wolfgang Jeltsch wrote: > Hi! > > Before starting with generics support at the type level, please first > improve the generics support at the value level. When I looked at it the > last time, there were some apparent leftovers in the form

Convenient URL alias for Trac tickets

2017-09-01 Thread Ben Gamari
Hello everyone, Earlier today a contributor requested that we have an easier-to-remember URL for Trac tickets. Consequently, I've configured ghc.haskell.org to redirect URLs of the form, http://ghc.haskell.org/t/$n to the appropriate Trac ticket. For instance,

Re: Convenient URL alias for Trac tickets

2017-09-01 Thread Herbert Valerio Riedel
Good idea! ...btw, note that a couple years ago, I set up the little known http://ghc.haskell.org/ticket/1234 alias... :-) On Fri, Sep 1, 2017 at 8:26 PM, Ben Gamari wrote: > Hello everyone, > > Earlier today a contributor requested that we have an easier-to-remember