0_unused_var_error.erl

-module(sample).
-export([hello/1]).

hello(X) ->
  case do_something(X) of
    false ->
      A = false;
    Res ->
      { A, B } = Res,
      do_something(A),
      do_something(B)
  end,
  ThisShouldNotFail = A,
  ok.

do_something(X) ->
  external:do_something(X).

1_error.txt

crash reason: {function_clause,
                  [{v3_kernel,lit_vars,
                       [{ivalues,
                            [11,{file,"sample.erl"}],
                            [{k_var,[],ker4},{k_atom,[],ok}]}],
                       [{file,"v3_kernel.erl"},{line,1749}]},
                   {v3_kernel,uexpr,3,[{file,"v3_kernel.erl"},{line,1628}]},
                   {v3_kernel,ubody,3,[{file,"v3_kernel.erl"},{line,1408}]},
                   {v3_kernel,ubody,3,[{file,"v3_kernel.erl"},{line,1409}]},
                   {v3_kernel,umatch,3,[{file,"v3_kernel.erl"},{line,1716}]},
                   {v3_kernel,'-umatch_list/3-anonymous-0-',3,
                       [{file,"v3_kernel.erl"},{line,1735}]},
                   {v3_kernel,umatch,3,[{file,"v3_kernel.erl"},{line,1711}]},
                   {v3_kernel,'-umatch_list/3-anonymous-0-',3,
                       [{file,"v3_kernel.erl"},{line,1735}]}]}