anchor.diff:    {KnownExtensions, UnknownExtensions} = group_extensions( tl(Parts) ),
   
     ReversedUnknownExtensions = if
  -    UnknownExtensions != [] ->
  +    UnknownExtensions /= [] ->
         UnknownExtensions = lists:reverse(UnknownExtensions);
       true -> []
     end,
  
positive.code: 
  
  group_extensions([]) ->
    {[], []}.
  
  group_extensions(Extensions) ->
    ReversedExtensions = lists:reverse(Extensions),
    PartitionFunction = fun(Extension)->
      lists:member(Extension, Dict.keys(Compilers))
    end,
    lists:partition(PartitionFunction, ReversedExtensions).
  
negative.code: 
  
  compilers() ->
    [{"scss", wilcog_scss_compiler},
     {"js", wilcog_javascript_compiler},
     {"css", wilcog_css_compiler},
     {"coffee", wilcog_coffeescript_compiler}].
  
  
  compiled_name_for(_SourceFilename, Basename, []) ->
    Basename;
  compiled_name_for(SourceFilename, Basename, KnownExtensions) ->
    Parts = [Basename] ++ [compute_extension(SourceFilename, lists:last(KnownExtensions))],
    string:join(Parts, ".").
  