prevent iex process termination when autocomplete on a single dot (.)

Author: tonini

lib/iex/lib/iex/autocomplete.ex

@@ -51,7 +51,7 @@ defmodule IEx.Autocomplete do
 
  def expand([h|t]=expr) do
  cond do
- h === ?. ->
+ h === ?. and t != []->
  expand_dot reduce(t)
  h === ?: ->
  expand_erlang_modules

lib/iex/test/iex/autocomplete_test.exs

@@ -21,7 +21,7 @@ defmodule IEx.AutocompleteTest do
  end
 
  test :erlang_module_multiple_values_completion do
- {:yes, '', list} = expand(':user') 
+ {:yes, '', list} = expand(':user')
  assert length(list) > 1
  end
 
@@ -35,6 +35,7 @@ defmodule IEx.AutocompleteTest do
  end
 
  test :elixir_no_completion do
+ assert expand('.') == {:no, '', []}
  assert expand('Xyz') == {:no, '', []}
  end
 
@@ -48,7 +49,7 @@ defmodule IEx.AutocompleteTest do
  end
 
  test :elixir_submodule_no_completion do
- assert expand('IEx.Xyz') == {:no, '', []} 
+ assert expand('IEx.Xyz') == {:no, '', []}
  end
 
  test :elixir_function_completion do