Function-name completion in haskell-indentation-mode

[gracjan]

In haskell-indent, it also completes the function name.

Suppose following situation:

fib :: Int -> Int
fib 0 = 1
--       ^ cursor here

When I hit C-j and TAB twice, haskell-indent completes the function name:

fib :: Int -> Int
fib 0 = 1
fib 

But with haskell-indentation, function name is not completed.

[gracjan]

This one is blocking #1065.

[gracjan]

Note that where is overloaded keyword in Haskell, because it is used in a couple of places:

• function declaration ... where
• module ... where
• class ... where
• instance ... where
• data ... where

We would like to provide completions where where introduces function declaration scope, that is all cases except the data ... where case when no two constructors should have the same name.