copilot-libraries: Remove deprecated function Copilot.Library.Utils.(!!). Refs #599.

The function `copilot-libraries:Copilot.Library.Utils.(!!)` was deprecated due
to the introduction of a new, common interface to interact with structures and
arrays. The original function was deprecated in Copilot 4 and no messages have
been received requesting that it be kept in this library. Per our internal
policy of waiting 3 versions from deprecation until a public interface
declaration can be removed, this function can now be removed.

This commit removes the function
`copilot-libraries:Copilot.Library.Utils.(!!)`, and adjusts any imports that
were hiding either the same function or equally named functions to avoid
clashes, since they would no longer occur.

Author: ivanperez-keera

copilot-libraries/src/Copilot/Library/Libraries.hs

@@ -23,6 +23,6 @@ import Copilot.Library.LTL
 import Copilot.Library.PTLTL
 import Copilot.Library.Statistics
 import Copilot.Library.RegExp
-import Copilot.Library.Utils      hiding ((!!))
+import Copilot.Library.Utils
 import Copilot.Library.Voting
 import Copilot.Library.Stacks

copilot-libraries/src/Copilot/Library/Utils.hs

@@ -13,10 +13,10 @@ module Copilot.Library.Utils
          -- ** Scans
          nscanl, nscanr, nscanl1, nscanr1,
          -- ** Indexing
-         case', (!!), (!!!))
+         case', (!!!))
 where
 
-import Copilot.Language hiding ((!!))
+import Copilot.Language
 import qualified Prelude as P
 
 -- | Given a stream, produce an infinite list of streams dropping an increasing
@@ -131,13 +131,6 @@ case' predicates alternatives =
                    P.++ "greater by one than the length of predicates list"
   in case'' predicates alternatives
 
--- | Index.
---
--- WARNING: Very expensive! Consider using this only for very short lists.
-(!!) :: (Typed a, Eq b, Num b, Typed b) => [Stream a] -> Stream b -> Stream a
-(!!) = (!!!)
-{-# DEPRECATED (!!) "This function is deprecated in Copilot 4. Use (!!!)." #-}
-
 -- | Index.
 --
 -- WARNING: Very expensive! Consider using this only for very short lists.