Core transform to set all line numbers to the same value (42). Useful for simulating huge Elixir macros.

same_line.erl

-module(same_line).
-export([core_transform/2]).

%%
%% erlc -pa . '+{core_transform,same_line}' <filename>.erl
%%

core_transform(Core, _Options) ->
    F = fun(Node) ->
                case cerl:get_ann(Node) of
                    [Line|Ann] when is_integer(Line) ->
                        cerl:set_ann(Node, [42|Ann]);
                    _Ann ->
                        Node
                end
        end,
    cerl_trees:map(F, Core).