<div dir="ltr">This is my favourite so far.<div><br></div><div><div>-module(bug).</div><div>f(X, [_]) when {{X}}, -X -> ok.</div><div><br></div><div>$ erl</div><div>Erlang/OTP 17 [RELEASE CANDIDATE 2] [erts-6.0] [source-a74e66a] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false]</div>

<div><br></div><div>Eshell V6.0  (abort with ^G)</div><div>1> c(bug).</div><div>Function: f/2</div><div>bug.erl: internal error in beam_type;</div><div>crash reason: {case_clause,{'EXIT',{{badmatch,false},</div>

<div>                      [{beam_utils,live_opt_block,4,</div><div>                                   [{file,"beam_utils.erl"},{line,785}]},</div><div>                       {beam_utils,live_opt,4,</div><div>                                   [{file,"beam_utils.erl"},{line,680}]},</div>

<div>                       {beam_utils,live_opt,1,</div><div>                                   [{file,"beam_utils.erl"},{line,207}]},</div><div>                       {beam_type,function,1,</div><div>                                  [{file,"beam_type.erl"},{line,33}]},</div>

<div>                       {beam_type,'-module/2-lc$^0/1-0-',1,</div><div>                                  [{file,"beam_type.erl"},{line,28}]},</div><div>                       {beam_type,module,2,[{file,"beam_type.erl"},{line,28}]},</div>

<div>                       {compile,'-select_passes/2-anonymous-2-',2,</div><div>                                [{file,"compile.erl"},{line,493}]},</div><div>                       {compile,'-internal_comp/4-anonymous-1-',2,</div>

<div>                                [{file,"compile.erl"},{line,290}]}]}}}</div><div><br></div><div>  in function  compile:'-select_passes/2-anonymous-2-'/2 (compile.erl, line 493)</div><div>  in call from compile:'-internal_comp/4-anonymous-1-'/2 (compile.erl, line 290)</div>

<div>  in call from compile:fold_comp/3 (compile.erl, line 308)</div><div>  in call from compile:internal_comp/4 (compile.erl, line 292)</div><div>  in call from compile:'-do_compile/2-anonymous-0-'/2 (compile.erl, line 153)</div>

<div>bug.erl:2: Warning: function f/2 is unused</div><div>error</div></div><div><br></div><div>/ Ulf</div></div>