Hi Levent, that seems to be this commit, part of the making-ghc-deterministic effort: https://ghc.haskell.org/trac/ghc/ticket/4012#comment:213 CC @niteria who might be answer your question. Niklas On 29/07/17 08:12, Levent Erkok wrote:

I'm trying to port some plugin code from GHC 8.0.2 to GHC 8.2.1; alas I'm getting an error suggesting that TyCon is no longer an instance of Ord:

Data/SBV/Plugin/Analyze.hs:580:33: error: • No instance for (Ord TyCon) arising from a use of ‘M.lookup’ There are instances for similar types: instance Ord GHC.Types.TyCon -- Defined in ‘GHC.Classes’ • In the expression: k `M.lookup` tcMap In the expression: case k `M.lookup` tcMap of Just knd -> return knd Nothing -> unknown In a case alternative: Just k -> case k `M.lookup` tcMap of Just knd -> return knd Nothing -> unknown | 580 | Just k -> case k `M.lookup` tcMap of | ^^^^^^^^^^^^^^^^^^

I was using TyCon's as a key in a map, but that code is no longer compiling. I've looked through the release notes but couldn't find what the new mechanism is.

I'd appreciate if someone can point me in the right direction regarding how to use TyCon as a map key..

Levent Erkok writes:

I'm trying to port some plugin code from GHC 8.0.2 to GHC 8.2.1; alas I'm getting an error suggesting that TyCon is no longer an instance of Ord:

Data/SBV/Plugin/Analyze.hs:580:33: error: • No instance for (Ord TyCon) arising from a use of ‘M.lookup’ There are instances for similar types: instance Ord GHC.Types.TyCon -- Defined in ‘GHC.Classes’ • In the expression: k `M.lookup` tcMap In the expression: case k `M.lookup` tcMap of Just knd -> return knd Nothing -> unknown In a case alternative: Just k -> case k `M.lookup` tcMap of Just knd -> return knd Nothing -> unknown | 580 | Just k -> case k `M.lookup` tcMap of | ^^^^^^^^^^^^^^^^^^

Hmm. I am unable to reproduce this, $ ghci λ> import Type.Reflection λ> let tc = typeRepTyCon (typeRep @Int) λ> tc == tc True Does that work for you? Cheers, - Ben

Sorry about being late to the conversation, but if you need a map from Type to something, go look at TypeMap in the TrieMap module. Edward Excerpts from Levent Erkok's message of 2017-07-28 23:12:32 -0700:

I'm trying to port some plugin code from GHC 8.0.2 to GHC 8.2.1; alas I'm getting an error suggesting that TyCon is no longer an instance of Ord:

Data/SBV/Plugin/Analyze.hs:580:33: error: • No instance for (Ord TyCon) arising from a use of ‘M.lookup’ There are instances for similar types: instance Ord GHC.Types.TyCon -- Defined in ‘GHC.Classes’ • In the expression: k `M.lookup` tcMap In the expression: case k `M.lookup` tcMap of Just knd -> return knd Nothing -> unknown In a case alternative: Just k -> case k `M.lookup` tcMap of Just knd -> return knd Nothing -> unknown | 580 | Just k -> case k `M.lookup` tcMap of | ^^^^^^^^^^^^^^^^^^

I was using TyCon's as a key in a map, but that code is no longer compiling. I've looked through the release notes but couldn't find what the new mechanism is.

I'd appreciate if someone can point me in the right direction regarding how to use TyCon as a map key..

Thanks,

-Levent.