Fix overridden BIFs

The filters in a list comprehension can be guard expressions or
an ordinary expressions.

If a guard expression is used as a filter, an exception will basically
mean the same as 'false':

  t() ->
    L = [{some_tag,42},an_atom],
    [X || X <- L, element(1, X) =:= some_tag]
    %% Returns [{some_tag,42}]

On the other hand, if an ordinary expression is used as a filter, there
will be an exception:

  my_element(N, T) -> element(N, T).

  t() ->
    L = [{some_tag,42},an_atom],
    [X || X <- L, my_element(1, X) =:= some_tag]
    %% Causes a 'badarg' exception when element(1, an_atom) is evaluated

It has been allowed for several releases to override a BIF with
a local function. Thus, if we define a function called element/2,
it will be called instead of the BIF element/2 within the module.
We must use the "erlang:" prefix to call the BIF.

Therefore, the following code is expected to work the same way as in
our second example above:

-compile({no_auto_import,[element/2]}).

element(N, T) ->
    erlang:element(N, T).

t() ->
    L = [{some_tag,42},an_atom],
    [X || X <- L, element(1, X) =:= some_tag].
    %% Causes a 'badarg' exception when element(1, an_atom) is evaluated

But the compiler refuses to compile the code with the following
diagnostic:

  call to local/imported function element/2 is illegal in guard

0 files changed, 0 insertions, 0 deletions