Bug when documenting object overloading

[thofma]

I just noticed the following bug while replacing Base.call in our code. This happens on 0.5 and latest master:

julia> type A end

julia> type B end

julia> @doc """a""" (a::A)() = a 
a

julia> @doc """b""" (a::B)() = a
WARNING: replacing docs for 'a :: Tuple{}' in module 'Main'.
a

julia> a = A()
A()
help?> a
search: any all abs Any ANY atan asin asec any! all! airy acsc acot acos abs2 atanh atand atan2 asinh

  b

This does not happen with "normal" functions.

edit: Of course one can easily work around it by changing the variable names in the signature.