<div dir="ltr"><div>-module(bug).<br></div><div>f() when false, is_map((true andalso b)#{a => 0}) -> ok.</div><div><br></div><div>$ erl</div><div>Erlang/OTP 17 [RELEASE CANDIDATE 2] [erts-6.0] [source-c2b4eab] [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/0</div><div>bug.erl: internal error in v3_codegen;</div><div>crash reason: {case_clause,{'EXIT',{{badmatch,[]},</div>

<div>                      [{v3_codegen,call_cg,7,</div><div>                                   [{file,"v3_codegen.erl"},{line,1123}]},</div><div>                       {v3_codegen,guard_cg,5,</div><div>                                   [{file,"v3_codegen.erl"},{line,1019}]},</div>

<div>                       {v3_codegen,'-guard_cg_list/6-anonymous-0-',4,</div><div>                                   [{file,"v3_codegen.erl"},{line,1062}]},</div><div>                       {v3_codegen,flatmapfoldl,3,</div>

<div>                                   [{file,"v3_codegen.erl"},{line,2165}]},</div><div>                       {v3_codegen,guard_cg_list,6,</div><div>                                   [{file,"v3_codegen.erl"},{line,1060}]},</div>

<div>                       {v3_codegen,protected_cg,7,</div><div>                                   [{file,"v3_codegen.erl"},{line,1032}]},</div><div>                       {v3_codegen,guard_clause_cg,4,</div>
<div>
                                   [{file,"v3_codegen.erl"},{line,999}]},</div><div>                       {v3_codegen,match_cg,5,</div><div>                                   [{file,"v3_codegen.erl"},{line,282}]}]}}}</div>

<div><br></div><div>  in function  compile:'-select_passes/2-anonymous-2-'/2 (compile.erl, line 495)</div><div>  in call from compile:'-internal_comp/4-anonymous-1-'/2 (compile.erl, line 292)</div><div>  in call from compile:fold_comp/3 (compile.erl, line 310)</div>

<div>  in call from compile:internal_comp/4 (compile.erl, line 294)</div><div>  in call from compile:'-do_compile/2-anonymous-0-'/2 (compile.erl, line 153)</div><div>bug.erl:2: Warning: function f/0 is unused</div>

<div>bug.erl:2: Warning: map construction will fail because of a type mismatch</div><div>bug.erl:2: Warning: the result of the expression is ignored (suppress the warning by assigning the expression to the _ variable)</div>

<div>error</div><div><br></div><div>/ Ulf</div><div><br></div></div>