internal error in core_dsetel_module

bm.erl

-module(bm).                                                       
-compile([export_all]).                                            
-record(rec, {f1 = 1, f2 = 2}).                                    
-record(rec2, {f2 = b, f3 = c}).                                   
                                                                   
tst(A, K) ->                                                       
    case true of                                                   
        true -> #rec{f2 = V} = #rec2{f2 = V} = A#rec{f1 = updated} 
    end,                                                           
    V.    
                                                         
11> c(bm).
Function: tst/2
bm.erl:none: internal error in core_dsetel_module;
crash reason: {{badmatch,error},
               [{sys_core_dsetel,visit,2,
                                 [{file,"sys_core_dsetel.erl"},{line,98}]},
                {sys_core_dsetel,visit,2,
                                 [{file,"sys_core_dsetel.erl"},{line,126}]},
                {sys_core_dsetel,visit,2,
                                 [{file,"sys_core_dsetel.erl"},{line,117}]},
                {sys_core_dsetel,visit_module_1,3,
                                 [{file,"sys_core_dsetel.erl"},{line,79}]},
                {sys_core_dsetel,visit_module,1,
                                 [{file,"sys_core_dsetel.erl"},{line,75}]},
                {sys_core_dsetel,module,2,
                                 [{file,"sys_core_dsetel.erl"},{line,70}]},
                {compile,core_dsetel_module,1,
                         [{file,"compile.erl"},{line,1150}]},
                {compile,'-internal_comp/4-anonymous-1-',2,
                         [{file,"compile.erl"},{line,269}]}]}
bm.erl:6: Warning: variable 'K' is unused
bm.erl:8: Warning: pattern cannot possibly match
error