davisp · March 21, 2022 17:23
diff --git a/couch_key_tree_21_vs_23.diff b/couch_key_tree_21_vs_23.diff
 --- couch_key_tree.21.S	2022-03-21 12:24:36.000000000 -0500
 +++ couch_key_tree.23.S	2022-03-21 12:21:59.000000000 -0500
 @@ -26,7 +26,7 @@

 {attributes, []}.

 -{labels, 303}.
 +{labels, 269}.


 {function, multi_merge, 2, 2}.
 @@ -37,10 +37,9 @@
     {allocate,2,2}.
     {move,{x,1},{y,0}}.
     {move,{x,0},{y,1}}.
 -    {make_fun2,{f,301},0,0,0}.
 -    {move,{x,0},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,1},{y,0}}.
 +    {make_fun2,{f,268},0,0,0}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_list,any,nil}}]}}.
 +    {swap,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",51}]}.
     {call_ext,1,{extfunc,lists,sort,1}}.
     {move,{y,1},{x,1}}.
 @@ -58,1107 +57,1182 @@
     {allocate_zero,1,2}.
     {move,nil,{x,2}}.
     {line,[{location,"couch_key_tree.erl",58}]}.
 -    {call,3,{f,7}}.
 -    {test,is_tuple,{f,5},[{x,0}]}.
 -    {test,test_arity,{f,5},[{x,0},2]}.
 +    {call,3,{f,6}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 => {t_list,any,nil},
 +                       2 => {t_atom,[internal_node,new_branch,new_leaf]}}}}]}}.
 +    {get_tuple_element,{x,0},0,{x,1}}.
     {get_tuple_element,{x,0},1,{y,0}}.
 -    {get_tuple_element,{x,0},0,{x,0}}.
 +    {move,{x,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",59}]}.
     {call_ext,1,{extfunc,lists,sort,1}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{y,0}]}}.
     {deallocate,1}.
     return.
 -  {label,5}.
 -    {line,[{location,"couch_key_tree.erl",58}]}.
 -    {badmatch,{x,0}}.


 -{function, merge_tree, 3, 7}.
 -  {label,6}.
 +{function, merge_tree, 3, 6}.
 +  {label,5}.
     {line,[{location,"couch_key_tree.erl",67}]}.
     {func_info,{atom,couch_key_tree},{atom,merge_tree},3}.
 -  {label,7}.
 -    {test,is_nonempty_list,{f,9},[{x,0}]}.
 +  {label,6}.
 +    {'%',{var_info,{x,2},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {test,is_nonempty_list,{f,8},[{x,0}]}.
     {get_list,{x,0},{x,3},{x,4}}.
 -    {test,is_tuple,{f,6},[{x,3}]}.
 -    {test,test_arity,{f,6},[{x,3},2]}.
 -    {test,is_tuple,{f,6},[{x,1}]}.
 -    {test,test_arity,{f,6},[{x,1},2]}.
 -    {allocate_zero,6,5}.
 -    {get_tuple_element,{x,3},0,{x,5}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {get_tuple_element,{x,1},0,{x,7}}.
 -    {get_tuple_element,{x,1},1,{x,8}}.
 +    {test,is_tuple,{f,5},[{x,3}]}.
 +    {test,test_arity,{f,5},[{x,3},2]}.
 +    {test,is_tuple,{f,5},[{x,1}]}.
 +    {test,test_arity,{f,5},[{x,1},2]}.
 +    {get_tuple_element,{x,3},0,{x,0}}.
 +    {get_tuple_element,{x,1},0,{x,5}}.
     {line,[{location,"couch_key_tree.erl",84}]}.
 -    {gc_bif,'-',{f,0},9,[{x,5},{x,7}],{x,0}}.
 -    {test_heap,4,9}.
 -    {move,{x,2},{y,5}}.
 -    {move,{x,1},{y,4}}.
 -    {move,{x,4},{y,3}}.
 -    {move,{x,3},{y,2}}.
 +    {gc_bif,'-',{f,0},6,[{x,0},{x,5}],{x,6}}.
 +    {allocate_heap,7,4,7}.
 +    {init,{y,0}}.
     {move,{x,5},{y,1}}.
 -    {move,{x,7},{y,0}}.
 -    {put_list,{x,6},nil,{x,6}}.
 -    {put_list,{x,8},nil,{x,2}}.
 -    {move,{x,0},{x,1}}.
 -    {move,{x,6},{x,0}}.
 +    {move,{x,0},{y,2}}.
 +    {move,{x,3},{y,3}}.
 +    {move,{x,4},{y,4}}.
 +    {move,{x,2},{y,5}}.
 +    {move,{x,1},{y,6}}.
 +    {get_tuple_element,{x,1},1,{x,0}}.
 +    {get_tuple_element,{x,3},1,{x,1}}.
 +    {put_list,{x,1},nil,{x,1}}.
 +    {put_list,{x,0},nil,{x,2}}.
 +    {move,{x,1},{x,0}}.
 +    {move,{x,6},{x,1}}.
     {line,[{location,"couch_key_tree.erl",84}]}.
 -    {call,3,{f,13}}.
 -    {test,is_tuple,{f,8},[{x,0}]}.
 -    {test,test_arity,{f,11},[{x,0},2]}.
 -    {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {test,is_nonempty_list,{f,11},[{x,1}]}.
 -    {get_list,{x,1},{x,3},{x,4}}.
 -    {test,is_nil,{f,11},[{x,4}]}.
 -    {move,{y,0},{x,1}}.
 -    {move,{x,3},{y,2}}.
 -    {move,{x,2},{y,4}}.
 -    {move,{y,1},{x,0}}.
 -    {trim,2,4}.
 -    {line,[{location,"couch_key_tree.erl",86}]}.
 +    {call,3,{f,12}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_union,
 +                     {t_atom,[fail]},
 +                     none,none,
 +                     {t_tuple,2,true,
 +                         #{1 => {t_cons,any,any},
 +                           2 => {t_atom,[internal_node,new_branch,new_leaf]}}},
 +                     none}}]}}.
 +    {move,{x,0},{y,0}}.
 +    {test,is_tuple,{f,7},[{x,0}]}.
 +    {get_tuple_element,{x,0},0,{x,0}}.
 +    {get_list,{x,0},{y,6},{x,0}}.
 +    {test,is_nil,{f,10},[{x,0}]}.
 +    {move,{y,1},{x,1}}.
 +    {move,{y,2},{x,0}}.
 +    {move,{y,0},{y,3}}.
 +    {trim,3,4}.
     {call_ext,2,{extfunc,erlang,min,2}}.
     {test_heap,5,1}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {put_list,{x,2},{y,3},{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{y,3}]}}.
 +    {put_list,{x,0},{y,2},{x,1}}.
     {move,{y,1},{x,0}}.
 -    {move,{y,2},{y,3}}.
 +    {move,{y,0},{y,3}}.
     {trim,3,1}.
     {line,[{location,"couch_key_tree.erl",87}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {get_tuple_element,{y,0},1,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1}]}}.
     {deallocate,1}.
     return.
 -  {label,8}.
 -    {test,is_eq_exact,{f,11},[{x,0},{atom,fail}]}.
 +  {label,7}.
     {test_heap,2,0}.
 -    {put_list,{y,2},{y,5},{x,2}}.
 -    {move,{y,4},{x,1}}.
 -    {move,{y,3},{x,0}}.
 -    {call_last,3,{f,7},6}.
 -  {label,9}.
 -    {test,is_nil,{f,6},[{x,0}]}.
 -    {test,is_nil,{f,10},[{x,2}]}.
 +    {put_list,{y,3},{y,5},{x,2}}.
 +    {move,{y,6},{x,1}}.
 +    {move,{y,4},{x,0}}.
 +    {call_last,3,{f,6},7}.
 +  {label,8}.
 +    {test,is_nil,{f,5},[{x,0}]}.
 +    {test,is_nil,{f,9},[{x,2}]}.
     {test_heap,5,2}.
 -    {put_list,{x,1},nil,{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{atom,new_leaf}}.
 +    {put_list,{x,1},nil,{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{atom,new_leaf}]}}.
     return.
 -  {label,10}.
 +  {label,9}.
     {test_heap,5,3}.
 -    {put_list,{x,1},{x,2},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{atom,new_branch}}.
 +    {put_list,{x,1},{x,2},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{atom,new_branch}]}}.
     return.
 -  {label,11}.
 +  {label,10}.
     {line,[{location,"couch_key_tree.erl",84}]}.
 -    {case_end,{x,0}}.
 +    {case_end,{y,0}}.


 -{function, merge_at, 3, 13}.
 -  {label,12}.
 +{function, merge_at, 3, 12}.
 +  {label,11}.
     {line,[{location,"couch_key_tree.erl",100}]}.
     {func_info,{atom,couch_key_tree},{atom,merge_at},3}.
 -  {label,13}.
 -    {test,is_nil,{f,14},[{x,2}]}.
 -    {move,{atom,fail},{x,0}}.
 -    return.
 -  {label,14}.
 -    {test,is_nil,{f,15},[{x,0}]}.
 -    {move,{atom,fail},{x,0}}.
 -    return.
 -  {label,15}.
 -    {test,is_nonempty_list,{f,18},[{x,2}]}.
 +  {label,12}.
 +    {'%',{var_info,{x,1},[{type,number}]}}.
 +    {'%',{var_info,{x,2},[{type,{t_cons,any,any}}]}}.
 +    {test,is_ne_exact,{f,19},[{x,0},nil]}.
     {get_list,{x,2},{x,3},{x,4}}.
 -    {test,is_tuple,{f,18},[{x,3}]}.
 -    {test,test_arity,{f,18},[{x,3},3]}.
 -    {get_tuple_element,{x,3},0,{x,5}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {get_tuple_element,{x,3},2,{x,7}}.
 -    {test,is_nonempty_list,{f,17},[{x,7}]}.
 -    {get_tl,{x,7},{x,8}}.
 -    {test,is_nil,{f,18},[{x,8}]}.
 -    {test,is_nil,{f,18},[{x,4}]}.
 -    {test,is_lt,{f,18},[{integer,0},{x,1}]}.
 -    {allocate_zero,2,8}.
 +    {test,is_tuple,{f,14},[{x,3}]}.
 +    {test,test_arity,{f,14},[{x,3},3]}.
 +    {get_tuple_element,{x,3},2,{x,5}}.
 +    {test,is_nonempty_list,{f,13},[{x,5}]}.
 +    {get_tl,{x,5},{x,6}}.
 +    {test,is_nil,{f,14},[{x,6}]}.
 +    {test,is_nil,{f,14},[{x,4}]}.
 +    {test,is_lt,{f,14},[{integer,0},{x,1}]}.
     {line,[{location,"couch_key_tree.erl",107}]}.
 -    {gc_bif,'-',{f,0},8,[{x,1},{integer,1}],{x,1}}.
 -    {move,{x,7},{x,2}}.
 -    {move,{x,6},{y,0}}.
 -    {move,{x,5},{y,1}}.
 +    {gc_bif,'-',{f,0},6,[{x,1},{integer,1}],{x,1}}.
 +    {allocate,1,6}.
 +    {move,{x,3},{y,0}}.
 +    {move,{x,5},{x,2}}.
     {line,[{location,"couch_key_tree.erl",107}]}.
 -    {call,3,{f,13}}.
 -    {test,is_tuple,{f,16},[{x,0}]}.
 -    {test,test_arity,{f,26},[{x,0},2]}.
 +    {call,3,{f,12}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_union,
 +                     {t_atom,[fail]},
 +                     none,none,
 +                     {t_tuple,2,true,
 +                         #{1 => {t_cons,any,any},
 +                           2 => {t_atom,[internal_node,new_branch,new_leaf]}}},
 +                     none}}]}}.
 +    {test,is_tuple,{f,21},[{x,0}]}.
     {test_heap,9,1}.
 -    {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {put_tuple,3,{x,3}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 -    {put,{x,1}}.
 -    {put_list,{x,3},nil,{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 -    {deallocate,2}.
 -    return.
 -  {label,16}.
 -    {test,is_eq_exact,{f,26},[{x,0},{atom,fail}]}.
 -    {deallocate,2}.
 +    {get_tuple_element,{y,0},0,{x,1}}.
 +    {get_tuple_element,{y,0},1,{x,2}}.
 +    {get_tuple_element,{x,0},0,{x,3}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_tuple2,{x,1},{list,[{x,1},{x,2},{x,3}]}}.
 +    {put_list,{x,1},nil,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
 +    {deallocate,1}.
     return.
 -  {label,17}.
 -    {test,is_nil,{f,18},[{x,7}]}.
 -    {test,is_nil,{f,18},[{x,4}]}.
 -    {test,is_ge,{f,23},[{integer,0},{x,1}]}.
 -  {label,18}.
 -    {test,is_nonempty_list,{f,12},[{x,0}]}.
 -    {get_list,{x,0},{x,3},{x,4}}.
 -    {test,is_tuple,{f,24},[{x,3}]}.
 -    {test,test_arity,{f,24},[{x,3},3]}.
 -    {get_tuple_element,{x,3},0,{x,5}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {get_tuple_element,{x,3},2,{x,7}}.
 -    {test,is_lt,{f,21},[{x,1},{integer,0}]}.
 -    {allocate_zero,6,8}.
 +  {label,13}.
 +    {test,is_nil,{f,14},[{x,5}]}.
 +    {test,is_nil,{f,14},[{x,4}]}.
 +    {test,is_ge,{f,19},[{integer,0},{x,1}]}.
 +  {label,14}.
 +    {test,is_nonempty_list,{f,11},[{x,0}]}.
 +    {get_list,{x,0},{x,5},{x,6}}.
 +    {test,is_tuple,{f,20},[{x,5}]}.
 +    {test,test_arity,{f,20},[{x,5},3]}.
 +    {get_tuple_element,{x,5},0,{x,7}}.
 +    {get_tuple_element,{x,5},1,{x,8}}.
 +    {get_tuple_element,{x,5},2,{x,9}}.
 +    {test,is_lt,{f,17},[{x,1},{integer,0}]}.
     {line,[{location,"couch_key_tree.erl",118}]}.
 -    {gc_bif,'+',{f,0},8,[{x,1},{integer,1}],{x,0}}.
 -    {move,{x,1},{y,1}}.
 +    {gc_bif,'+',{f,0},10,[{x,1},{integer,1}],{x,0}}.
 +    {allocate,6,10}.
 +    {move,{x,7},{y,0}}.
 +    {move,{x,8},{y,1}}.
 +    {move,{x,5},{y,2}}.
 +    {move,{x,6},{y,3}}.
 +    {move,{x,2},{y,4}}.
 +    {move,{x,1},{y,5}}.
     {move,{x,0},{x,1}}.
 -    {move,{x,2},{y,0}}.
 -    {move,{x,4},{y,2}}.
 -    {move,{x,3},{y,3}}.
 -    {move,{x,6},{y,4}}.
 -    {move,{x,5},{y,5}}.
 -    {move,{x,7},{x,0}}.
 +    {move,{x,9},{x,0}}.
     {line,[{location,"couch_key_tree.erl",118}]}.
 -    {call,3,{f,13}}.
 -    {test,is_tuple,{f,19},[{x,0}]}.
 -    {test,test_arity,{f,28},[{x,0},2]}.
 +    {call,3,{f,12}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_union,
 +                     {t_atom,[fail]},
 +                     none,none,
 +                     {t_tuple,2,true,
 +                         #{1 => {t_cons,any,any},
 +                           2 => {t_atom,[internal_node,new_branch,new_leaf]}}},
 +                     none}}]}}.
 +    {test,is_tuple,{f,15},[{x,0}]}.
     {test_heap,9,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {put_tuple,3,{x,3}}.
 -    {put,{y,5}}.
 -    {put,{y,4}}.
 -    {put,{x,1}}.
 -    {put_list,{x,3},{y,2},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_tuple2,{x,1},{list,[{y,0},{y,1},{x,1}]}}.
 +    {put_list,{x,1},{y,3},{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,6}.
     return.
 -  {label,19}.
 -    {test,is_eq_exact,{f,28},[{x,0},{atom,fail}]}.
 -    {move,{y,1},{x,1}}.
 -    {move,{y,0},{x,2}}.
 -    {move,{y,2},{x,0}}.
 +  {label,15}.
 +    {move,{y,4},{x,2}}.
 +    {move,{y,5},{x,1}}.
 +    {move,{y,3},{x,0}}.
     {kill,{y,0}}.
     {kill,{y,1}}.
 -    {kill,{y,2}}.
 +    {kill,{y,3}}.
     {kill,{y,4}}.
     {kill,{y,5}}.
     {line,[{location,"couch_key_tree.erl",125}]}.
 -    {call,3,{f,13}}.
 -    {test,is_tuple,{f,20},[{x,0}]}.
 -    {test,test_arity,{f,27},[{x,0},2]}.
 +    {call,3,{f,12}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_union,
 +                     {t_atom,[fail]},
 +                     none,none,
 +                     {t_tuple,2,true,
 +                         #{1 => {t_cons,any,any},
 +                           2 => {t_atom,[internal_node,new_branch,new_leaf]}}},
 +                     none}}]}}.
 +    {test,is_tuple,{f,16},[{x,0}]}.
     {test_heap,5,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {put_list,{y,3},{x,1},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_list,{y,2},{x,1},{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,6}.
     return.
 -  {label,20}.
 -    {test,is_eq_exact,{f,27},[{x,0},{atom,fail}]}.
 +  {label,16}.
 +    {move,{atom,fail},{x,0}}.
     {deallocate,6}.
     return.
 -  {label,21}.
 -    {test,is_eq_exact,{f,12},[{x,1},{integer,0}]}.
 -    {test,is_nonempty_list,{f,24},[{x,2}]}.
 -    {get_list,{x,2},{x,8},{x,9}}.
 -    {test,is_tuple,{f,24},[{x,8}]}.
 -    {test,test_arity,{f,24},[{x,8},3]}.
 -    {test,is_nil,{f,24},[{x,9}]}.
 -    {get_tuple_element,{x,8},0,{x,10}}.
 -    {test,is_eq_exact,{f,22},[{x,10},{x,5}]}.
 -    {allocate,4,9}.
 -    {get_tuple_element,{x,8},1,{y,3}}.
 -    {get_tuple_element,{x,8},2,{x,1}}.
 -    {move,{x,4},{y,0}}.
 -    {move,{x,6},{y,1}}.
 -    {move,{x,5},{y,2}}.
 -    {move,{x,7},{x,0}}.
 +  {label,17}.
 +    {test,is_eq_exact,{f,11},[{x,1},{integer,0}]}.
 +    {test,is_tuple,{f,20},[{x,3}]}.
 +    {test,test_arity,{f,20},[{x,3},3]}.
 +    {test,is_nil,{f,20},[{x,4}]}.
 +    {get_tuple_element,{x,3},0,{x,4}}.
 +    {test,is_eq_exact,{f,18},[{x,4},{x,7}]}.
 +    {allocate,4,10}.
 +    {move,{x,3},{y,0}}.
 +    {move,{x,7},{y,1}}.
 +    {move,{x,8},{y,2}}.
 +    {move,{x,6},{y,3}}.
 +    {get_tuple_element,{x,3},2,{x,1}}.
 +    {move,{x,9},{x,0}}.
     {line,[{location,"couch_key_tree.erl",133}]}.
 -    {call,2,{f,32}}.
 -    {test,is_tuple,{f,29},[{x,0}]}.
 -    {test,test_arity,{f,29},[{x,0},2]}.
 -    {get_tuple_element,{x,0},0,{x,3}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {move,{y,3},{x,1}}.
 -    {move,{y,1},{x,0}}.
 -    {move,{x,3},{y,1}}.
 -    {move,{x,2},{y,3}}.
 +    {call,2,{f,23}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{2 => {t_atom,[internal_node,new_branch,new_leaf]}}}}]}}.
 +    {get_tuple_element,{y,0},1,{x,1}}.
 +    {move,{y,2},{x,2}}.
 +    {move,{x,0},{y,2}}.
 +    {trim,1,3}.
 +    {move,{x,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",134}]}.
 -    {call,2,{f,189}}.
 +    {call,2,{f,162}}.
     {test_heap,9,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{y,2}}.
 -    {put,{x,0}}.
 -    {put,{y,1}}.
 -    {put_list,{x,1},{y,0},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{y,3}}.
 -    {deallocate,4}.
 +    {get_tuple_element,{y,1},0,{x,1}}.
 +    {get_tuple_element,{y,1},1,{x,2}}.
 +    {put_tuple2,{x,0},{list,[{y,0},{x,0},{x,1}]}}.
 +    {put_list,{x,0},{y,2},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,2}]}}.
 +    {deallocate,3}.
     return.
 -  {label,22}.
 -    {test,is_lt,{f,24},[{x,10},{x,5}]}.
 -  {label,23}.
 +  {label,18}.
 +    {test,is_lt,{f,20},[{x,4},{x,7}]}.
 +  {label,19}.
     {move,{atom,fail},{x,0}}.
     return.
 -  {label,24}.
 -    {test,is_eq_exact,{f,12},[{x,1},{integer,0}]}.
 -    {allocate,1,5}.
 +  {label,20}.
 +    {test,is_eq_exact,{f,11},[{x,1},{integer,0}]}.
 +    {allocate,1,7}.
 +    {move,{x,5},{y,0}}.
     {move,{integer,0},{x,1}}.
 -    {move,{x,3},{y,0}}.
 -    {move,{x,4},{x,0}}.
 +    {move,{x,6},{x,0}}.
     {line,[{location,"couch_key_tree.erl",140}]}.
 -    {call,3,{f,13}}.
 -    {test,is_tuple,{f,25},[{x,0}]}.
 -    {test,test_arity,{f,30},[{x,0},2]}.
 +    {call,3,{f,12}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_union,
 +                     {t_atom,[fail]},
 +                     none,none,
 +                     {t_tuple,2,true,
 +                         #{1 => {t_cons,any,any},
 +                           2 => {t_atom,[internal_node,new_branch,new_leaf]}}},
 +                     none}}]}}.
 +    {test,is_tuple,{f,21},[{x,0}]}.
     {test_heap,5,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
     {put_list,{y,0},{x,1},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,1}.
     return.
 -  {label,25}.
 -    {test,is_eq_exact,{f,30},[{x,0},{atom,fail}]}.
 +  {label,21}.
 +    {move,{atom,fail},{x,0}}.
     {deallocate,1}.
     return.
 -  {label,26}.
 -    {line,[{location,"couch_key_tree.erl",107}]}.
 -    {case_end,{x,0}}.
 -  {label,27}.
 -    {line,[{location,"couch_key_tree.erl",125}]}.
 -    {case_end,{x,0}}.
 -  {label,28}.
 -    {line,[{location,"couch_key_tree.erl",118}]}.
 -    {case_end,{x,0}}.
 -  {label,29}.
 -    {line,[{location,"couch_key_tree.erl",133}]}.
 -    {badmatch,{x,0}}.
 -  {label,30}.
 -    {line,[{location,"couch_key_tree.erl",140}]}.
 -    {case_end,{x,0}}.


 -{function, merge_extend, 2, 32}.
 -  {label,31}.
 +{function, merge_extend, 2, 23}.
 +  {label,22}.
     {line,[{location,"couch_key_tree.erl",147}]}.
     {func_info,{atom,couch_key_tree},{atom,merge_extend},2}.
 -  {label,32}.
 -    {test,is_nil,{f,33},[{x,0}]}.
 -    {test,is_ne_exact,{f,33},[{x,1},nil]}.
 +  {label,23}.
 +    {test,is_nil,{f,24},[{x,0}]}.
 +    {test,is_ne_exact,{f,25},[{x,1},nil]}.
     {test_heap,3,2}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{atom,new_leaf}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{atom,new_leaf}]}}.
     return.
 -  {label,33}.
 -    {test,is_nil,{f,34},[{x,1}]}.
 +  {label,24}.
 +    {test,is_nil,{f,26},[{x,1}]}.
 +  {label,25}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{atom,internal_node}}.
 -    {move,{x,1},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{atom,internal_node}]}}.
     return.
 -  {label,34}.
 -    {test,is_nonempty_list,{f,31},[{x,0}]}.
 +  {label,26}.
 +    {test,is_nonempty_list,{f,22},[{x,0}]}.
     {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,36},[{x,2}]}.
 -    {test,test_arity,{f,36},[{x,2},3]}.
 -    {get_tuple_element,{x,2},0,{x,4}}.
 -    {get_tuple_element,{x,2},1,{x,5}}.
 -    {get_tuple_element,{x,2},2,{x,6}}.
 -    {test,is_nonempty_list,{f,36},[{x,1}]}.
 -    {get_list,{x,1},{x,7},{x,8}}.
 -    {test,is_tuple,{f,36},[{x,7}]}.
 -    {test,test_arity,{f,36},[{x,7},3]}.
 -    {test,is_nil,{f,36},[{x,8}]}.
 -    {get_tuple_element,{x,7},0,{x,9}}.
 -    {test,is_eq_exact,{f,35},[{x,9},{x,4}]}.
 +    {test,is_tuple,{f,28},[{x,2}]}.
 +    {test,test_arity,{f,28},[{x,2},3]}.
 +    {test,is_nonempty_list,{f,28},[{x,1}]}.
 +    {get_list,{x,1},{x,4},{x,5}}.
 +    {test,is_tuple,{f,28},[{x,4}]}.
 +    {test,test_arity,{f,28},[{x,4},3]}.
 +    {get_tuple_element,{x,4},1,{x,6}}.
 +    {test,is_nil,{f,28},[{x,5}]}.
 +    {get_tuple_element,{x,4},0,{x,5}}.
 +    {get_tuple_element,{x,2},0,{x,7}}.
 +    {test,is_eq_exact,{f,27},[{x,5},{x,7}]}.
     {allocate,4,8}.
 -    {get_tuple_element,{x,7},1,{y,3}}.
 -    {get_tuple_element,{x,7},2,{x,1}}.
 -    {move,{x,3},{y,0}}.
 -    {move,{x,5},{y,1}}.
 -    {move,{x,4},{y,2}}.
 -    {move,{x,6},{x,0}}.
 +    {move,{x,6},{y,0}}.
 +    {move,{x,7},{y,1}}.
 +    {move,{x,2},{y,2}}.
 +    {move,{x,3},{y,3}}.
 +    {get_tuple_element,{x,4},2,{x,1}}.
 +    {get_tuple_element,{x,2},2,{x,0}}.
     {line,[{location,"couch_key_tree.erl",161}]}.
 -    {call,2,{f,32}}.
 -    {test,is_tuple,{f,39},[{x,0}]}.
 -    {test,test_arity,{f,39},[{x,0},2]}.
 -    {get_tuple_element,{x,0},0,{x,3}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {move,{y,3},{x,1}}.
 -    {move,{y,1},{x,0}}.
 -    {move,{x,3},{y,1}}.
 -    {move,{x,2},{y,3}}.
 +    {call,2,{f,23}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{2 => {t_atom,[internal_node,new_branch,new_leaf]}}}}]}}.
 +    {get_tuple_element,{y,2},1,{x,1}}.
 +    {move,{x,0},{y,2}}.
 +    {move,{y,0},{x,2}}.
 +    {move,{x,1},{x,0}}.
 +    {move,{x,2},{x,1}}.
 +    {trim,1,3}.
     {line,[{location,"couch_key_tree.erl",162}]}.
 -    {call,2,{f,189}}.
 +    {call,2,{f,162}}.
     {test_heap,9,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{y,2}}.
 -    {put,{x,0}}.
 -    {put,{y,1}}.
 -    {put_list,{x,1},{y,0},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{y,3}}.
 -    {deallocate,4}.
 +    {get_tuple_element,{y,1},0,{x,1}}.
 +    {get_tuple_element,{y,1},1,{x,2}}.
 +    {put_tuple2,{x,0},{list,[{y,0},{x,0},{x,1}]}}.
 +    {put_list,{x,0},{y,2},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,2}]}}.
 +    {deallocate,3}.
     return.
 -  {label,35}.
 -    {test,is_lt,{f,36},[{x,9},{x,4}]}.
 -    {test_heap,5,8}.
 -    {put_list,{x,7},{x,0},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{atom,new_branch}}.
 +  {label,27}.
 +    {test,is_lt,{f,28},[{x,5},{x,7}]}.
 +    {test_heap,5,5}.
 +    {put_list,{x,4},{x,0},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{atom,new_branch}]}}.
     return.
 -  {label,36}.
 +  {label,28}.
     {allocate,2,4}.
 -    {move,{x,3},{y,0}}.
 -    {move,{x,2},{y,1}}.
 +    {move,{x,2},{y,0}}.
 +    {move,{x,3},{y,1}}.
     {move,{x,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",173}]}.
 -    {call,2,{f,32}}.
 -    {test,is_tuple,{f,40},[{x,0}]}.
 -    {test,test_arity,{f,40},[{x,0},2]}.
 +    {call,2,{f,23}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{2 => {t_atom,[internal_node,new_branch,new_leaf]}}}}]}}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
     {line,[{location,"couch_key_tree.erl",175}]}.
 -    {gc_bif,length,{f,0},3,[{x,1}],{x,0}}.
 +    {gc_bif,length,{f,0},2,[{x,1}],{x,2}}.
     {line,[{location,"couch_key_tree.erl",175}]}.
 -    {gc_bif,length,{f,0},3,[{y,0}],{x,3}}.
 -    {move,{x,1},{y,0}}.
 -    {test,is_eq_exact,{f,37},[{x,0},{x,3}]}.
 -    {move,{x,2},{x,0}}.
 -    {jump,{f,38}}.
 -  {label,37}.
 -    {move,{atom,new_branch},{x,0}}.
 -  {label,38}.
 -    {test_heap,5,1}.
 -    {put_list,{y,1},{y,0},{x,1}}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{x,1}}.
 -    {put,{x,0}}.
 -    {move,{x,2},{x,0}}.
 +    {gc_bif,length,{f,0},3,[{y,1}],{x,3}}.
 +    {test,is_eq_exact,{f,29},[{x,2},{x,3}]}.
 +    {test_heap,5,2}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_list,{y,0},{x,1},{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
 +    {deallocate,2}.
 +    return.
 +  {label,29}.
 +    {test_heap,5,2}.
 +    {put_list,{y,0},{x,1},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{atom,new_branch}]}}.
     {deallocate,2}.
     return.
 -  {label,39}.
 -    {line,[{location,"couch_key_tree.erl",161}]}.
 -    {badmatch,{x,0}}.
 -  {label,40}.
 -    {line,[{location,"couch_key_tree.erl",173}]}.
 -    {badmatch,{x,0}}.


 -{function, find_missing, 2, 42}.
 -  {label,41}.
 +{function, find_missing, 2, 31}.
 +  {label,30}.
     {line,[{location,"couch_key_tree.erl",181}]}.
     {func_info,{atom,couch_key_tree},{atom,find_missing},2}.
 -  {label,42}.
 -    {test,is_nil,{f,43},[{x,1}]}.
 +  {label,31}.
 +    {test,is_nil,{f,32},[{x,1}]}.
     {move,nil,{x,0}}.
     return.
 -  {label,43}.
 -    {test,is_nonempty_list,{f,44},[{x,0}]}.
 +  {label,32}.
 +    {test,is_nonempty_list,{f,33},[{x,0}]}.
     {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,41},[{x,2}]}.
 -    {test,test_arity,{f,41},[{x,2},2]}.
 -    {get_tuple_element,{x,2},0,{x,4}}.
 -    {get_tuple_element,{x,2},1,{x,5}}.
 -    {test,is_tuple,{f,41},[{x,5}]}.
 -    {test,test_arity,{f,41},[{x,5},3]}.
 -    {allocate,4,6}.
 +    {test,is_tuple,{f,30},[{x,2}]}.
 +    {test,test_arity,{f,30},[{x,2},2]}.
 +    {get_tuple_element,{x,2},1,{x,4}}.
 +    {test,is_tuple,{f,30},[{x,4}]}.
 +    {test,test_arity,{f,30},[{x,4},3]}.
 +    {allocate,4,5}.
 +    {move,{x,4},{y,1}}.
 +    {move,{x,3},{y,2}}.
 +    {move,{x,1},{y,3}}.
 +    {get_tuple_element,{x,2},0,{y,0}}.
     {move,{x,1},{x,0}}.
 -    {move,{x,4},{x,1}}.
 -    {move,{x,0},{y,0}}.
 -    {move,{x,5},{y,1}}.
 -    {move,{x,1},{y,2}}.
 -    {move,{x,3},{y,3}}.
 +    {move,{y,0},{x,1}}.
     {line,[{location,"couch_key_tree.erl",186}]}.
 -    {call,2,{f,296}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,2},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,2},{y,0}}.
 +    {call,2,{f,263}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {move,{y,0},{x,2}}.
 +    {swap,{y,3},{x,0}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",187}]}.
 -    {call,2,{f,291}}.
 +    {call,2,{f,258}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {test_heap,2,1}.
     {put_list,{y,1},nil,{x,1}}.
 -    {move,{x,0},{y,1}}.
 -    {move,{y,0},{x,2}}.
 -    {move,{y,2},{x,0}}.
 -    {kill,{y,2}}.
 -    {trim,1,3}.
 +    {move,{y,3},{x,3}}.
 +    {move,{x,0},{y,3}}.
 +    {move,{y,0},{x,0}}.
 +    {move,{x,3},{x,2}}.
 +    {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",188}]}.
 -    {call,3,{f,46}}.
 +    {call,3,{f,35}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {move,{x,0},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {trim,2,1}.
 +    {move,{y,1},{x,0}}.
 +    {kill,{y,1}}.
     {line,[{location,"couch_key_tree.erl",189}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
 -    {call_last,2,{f,42},1}.
 -  {label,44}.
 -    {test,is_nil,{f,41},[{x,0}]}.
 +    {call_last,2,{f,31},2}.
 +  {label,33}.
 +    {test,is_nil,{f,30},[{x,0}]}.
     {move,{x,1},{x,0}}.
     return.


 -{function, find_missing_simple, 3, 46}.
 -  {label,45}.
 +{function, find_missing_simple, 3, 35}.
 +  {label,34}.
     {line,[{location,"couch_key_tree.erl",191}]}.
     {func_info,{atom,couch_key_tree},{atom,find_missing_simple},3}.
 -  {label,46}.
 -    {test,is_nil,{f,47},[{x,2}]}.
 +  {label,35}.
 +    {'%',{var_info,{x,2},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {test,is_nil,{f,36},[{x,2}]}.
     {move,nil,{x,0}}.
     return.
 -  {label,47}.
 -    {test,is_nonempty_list,{f,48},[{x,1}]}.
 +  {label,36}.
 +    {test,is_nonempty_list,{f,37},[{x,1}]}.
     {get_list,{x,1},{x,3},{x,4}}.
 -    {test,is_tuple,{f,45},[{x,3}]}.
 -    {test,test_arity,{f,45},[{x,3},3]}.
 +    {test,is_tuple,{f,34},[{x,3}]}.
 +    {test,test_arity,{f,34},[{x,3},3]}.
     {allocate,5,5}.
 -    {get_tuple_element,{x,3},0,{y,1}}.
 -    {get_tuple_element,{x,3},2,{y,2}}.
 +    {move,{x,3},{y,1}}.
 +    {move,{x,4},{y,2}}.
 +    {move,{x,2},{y,3}}.
 +    {move,{x,0},{y,4}}.
 +    {get_tuple_element,{x,3},2,{y,0}}.
     {move,{x,0},{x,1}}.
 -    {move,{x,2},{y,0}}.
 -    {move,{x,1},{y,3}}.
 -    {move,{x,4},{y,4}}.
     {move,{x,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",196}]}.
 -    {call,2,{f,286}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,3},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,2},{y,0}}.
 +    {call,2,{f,254}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {move,{y,4},{x,2}}.
 +    {swap,{y,3},{x,0}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",197}]}.
 -    {call,2,{f,281}}.
 +    {call,2,{f,250}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {test_heap,5,1}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{y,3}}.
 -    {put,{y,1}}.
 -    {move,{x,0},{y,1}}.
 -    {put_list,{x,2},nil,{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {trim,1,4}.
 +    {get_tuple_element,{y,1},0,{x,1}}.
 +    {put_tuple2,{x,1},{list,[{y,4},{x,1}]}}.
 +    {put_list,{x,1},nil,{x,1}}.
 +    {move,{y,3},{x,2}}.
 +    {move,{x,0},{y,3}}.
 +    {kill,{y,1}}.
 +    {move,{x,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",199}]}.
     {call_ext,2,{extfunc,erlang,'--',2}}.
     {line,[{location,"couch_key_tree.erl",200}]}.
 -    {gc_bif,'+',{f,0},1,[{y,2},{integer,1}],{x,1}}.
 +    {gc_bif,'+',{f,0},1,[{y,4},{integer,1}],{x,1}}.
     {move,{x,0},{x,2}}.
     {move,{x,1},{x,0}}.
 -    {move,{y,1},{x,1}}.
 -    {kill,{y,1}}.
 +    {move,{y,0},{x,1}}.
 +    {trim,2,3}.
     {line,[{location,"couch_key_tree.erl",200}]}.
 -    {call,3,{f,46}}.
 -    {move,{y,3},{x,1}}.
 +    {call,3,{f,35}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {move,{y,0},{x,1}}.
     {move,{x,0},{x,2}}.
     {move,{y,2},{x,0}}.
 -    {kill,{y,2}}.
 -    {kill,{y,3}}.
 +    {move,{y,1},{y,2}}.
 +    {trim,2,1}.
     {line,[{location,"couch_key_tree.erl",201}]}.
 -    {call,3,{f,46}}.
 +    {call,3,{f,35}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",201}]}.
 -    {call_ext_last,2,{extfunc,erlang,'++',2},4}.
 -  {label,48}.
 -    {test,is_nil,{f,45},[{x,1}]}.
 +    {call_ext_last,2,{extfunc,erlang,'++',2},1}.
 +  {label,37}.
 +    {test,is_nil,{f,34},[{x,1}]}.
     {move,{x,2},{x,0}}.
     return.


 -{function, filter_leafs, 4, 50}.
 -  {label,49}.
 +{function, filter_leafs, 4, 39}.
 +  {label,38}.
     {line,[{location,"couch_key_tree.erl",203}]}.
     {func_info,{atom,couch_key_tree},{atom,filter_leafs},4}.
 -  {label,50}.
 -    {test,is_nonempty_list,{f,52},[{x,0}]}.
 -    {get_list,{x,0},{x,4},{x,5}}.
 -    {test,is_tuple,{f,49},[{x,4}]}.
 -    {test,test_arity,{f,49},[{x,4},2]}.
 -    {get_tuple_element,{x,4},0,{x,6}}.
 -    {get_tuple_element,{x,4},1,{x,7}}.
 -    {test,is_nonempty_list,{f,49},[{x,7}]}.
 -    {get_hd,{x,7},{x,8}}.
 -    {test,is_tuple,{f,49},[{x,8}]}.
 -    {test,test_arity,{f,49},[{x,8},2]}.
 -    {allocate_heap,7,3,9}.
 -    {get_tuple_element,{x,8},0,{y,0}}.
 -    {move,{x,3},{y,6}}.
 +  {label,39}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
 +    {'%',
 +        {var_info,
 +            {x,2},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
 +    {'%',{var_info,{x,3},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {test,is_nonempty_list,{f,41},[{x,0}]}.
 +    {allocate_heap,7,3,4}.
 +    {move,{x,3},{y,4}}.
     {move,{x,2},{y,5}}.
 -    {move,{x,1},{y,4}}.
 -    {move,{x,5},{y,3}}.
 -    {move,{x,4},{y,2}}.
 -    {move,{x,6},{y,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,6}}.
 -    {put,{y,0}}.
 +    {move,{x,1},{y,6}}.
 +    {get_list,{x,0},{y,3},{y,2}}.
 +    {get_tuple_element,{y,3},1,{x,0}}.
 +    {get_hd,{x,0},{x,0}}.
 +    {get_tuple_element,{y,3},0,{y,1}}.
 +    {get_tuple_element,{x,0},0,{y,0}}.
 +    {put_tuple2,{x,0},{list,[{y,1},{y,0}]}}.
     {line,[{location,"couch_key_tree.erl",206}]}.
     {call_ext,2,{extfunc,lists,delete,2}}.
 -    {test,is_eq,{f,51},[{x,0},{y,4}]}.
 +    {test,is_eq,{f,40},[{x,0},{y,6}]}.
     {test_heap,2,0}.
 -    {put_list,{y,2},{y,5},{x,2}}.
 -    {move,{y,4},{x,1}}.
 -    {move,{y,6},{x,3}}.
 -    {move,{y,3},{x,0}}.
 -    {call_last,4,{f,50},7}.
 -  {label,51}.
 +    {put_list,{y,3},{y,5},{x,2}}.
 +    {move,{y,4},{x,3}}.
 +    {move,{y,6},{x,1}}.
 +    {move,{y,2},{x,0}}.
 +    {call_last,4,{f,39},7}.
 +  {label,40}.
     {test_heap,5,1}.
 -    {put_tuple,2,{x,4}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 -    {put_list,{x,4},{y,6},{x,3}}.
 +    {put_tuple2,{x,1},{list,[{y,1},{y,0}]}}.
 +    {put_list,{x,1},{y,4},{x,3}}.
     {move,{x,0},{x,1}}.
     {move,{y,5},{x,2}}.
 -    {move,{y,3},{x,0}}.
 -    {call_last,4,{f,50},7}.
 -  {label,52}.
 -    {test,is_nil,{f,49},[{x,0}]}.
 +    {move,{y,2},{x,0}}.
 +    {call_last,4,{f,39},7}.
 +  {label,41}.
     {test_heap,3,4}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,2}}.
 -    {put,{x,3}}.
 +    {put_tuple2,{x,0},{list,[{x,2},{x,3}]}}.
     return.


 -{function, remove_leafs, 2, 54}.
 -  {label,53}.
 +{function, remove_leafs, 2, 43}.
 +  {label,42}.
     {line,[{location,"couch_key_tree.erl",217}]}.
     {func_info,{atom,couch_key_tree},{atom,remove_leafs},2}.
 -  {label,54}.
 +  {label,43}.
     {allocate_zero,2,2}.
     {move,{x,1},{y,1}}.
     {line,[{location,"couch_key_tree.erl",219}]}.
 -    {call,1,{f,98}}.
 +    {call,1,{f,74}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
     {move,nil,{x,2}}.
     {move,nil,{x,3}}.
     {move,{y,1},{x,1}}.
     {kill,{y,1}}.
     {line,[{location,"couch_key_tree.erl",222}]}.
 -    {call,4,{f,50}}.
 -    {test,is_tuple,{f,55},[{x,0}]}.
 -    {test,test_arity,{f,55},[{x,0},2]}.
 +    {call,4,{f,39}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_list,
 +                               {t_tuple,2,true,
 +                                   #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                               nil},
 +                       2 => {t_list,{t_tuple,2,true,#{}},nil}}}}]}}.
 +    {get_tuple_element,{x,0},0,{x,1}}.
     {get_tuple_element,{x,0},1,{y,1}}.
 -    {get_tuple_element,{x,0},0,{x,0}}.
 +    {move,{x,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",225}]}.
 -    {call,1,{f,277}}.
 +    {call,1,{f,247}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{1 => number,
 +                           2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                     nil}}]}}.
     {line,[{location,"couch_key_tree.erl",224}]}.
     {call_ext,1,{extfunc,lists,sort,1}}.
     {move,{x,0},{y,0}}.
 -    {make_fun2,{f,271},0,0,0}.
 +    {make_fun2,{f,242},0,0,0}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_list,any,nil}}]}}.
     {move,{y,0},{x,2}}.
     {move,nil,{x,1}}.
     {trim,1,1}.
     {line,[{location,"couch_key_tree.erl",229}]}.
     {call_ext,3,{extfunc,lists,foldl,3}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{y,0}]}}.
     {deallocate,1}.
     return.
 -  {label,55}.
 -    {line,[{location,"couch_key_tree.erl",222}]}.
 -    {badmatch,{x,0}}.


 -{function, get_key_leafs, 2, 57}.
 -  {label,56}.
 +{function, get_key_leafs, 2, 45}.
 +  {label,44}.
     {line,[{location,"couch_key_tree.erl",245}]}.
     {func_info,{atom,couch_key_tree},{atom,get_key_leafs},2}.
 -  {label,57}.
 +  {label,45}.
     {move,nil,{x,2}}.
 -    {call_only,3,{f,59}}.
 +    {call_only,3,{f,47}}.


 -{function, get_key_leafs, 3, 59}.
 -  {label,58}.
 +{function, get_key_leafs, 3, 47}.
 +  {label,46}.
     {line,[{location,"couch_key_tree.erl",248}]}.
     {func_info,{atom,couch_key_tree},{atom,get_key_leafs},3}.
 -  {label,59}.
 -    {test,is_nil,{f,60},[{x,1}]}.
 +  {label,47}.
 +    {'%',
 +        {var_info,
 +            {x,2},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +                     nil}}]}}.
 +    {test,is_nil,{f,48},[{x,1}]}.
     {test_heap,3,3}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,2}}.
 -    {put,nil}.
 +    {put_tuple2,{x,0},{list,[{x,2},nil]}}.
     return.
 -  {label,60}.
 -    {test,is_nonempty_list,{f,61},[{x,0}]}.
 +  {label,48}.
 +    {test,is_nonempty_list,{f,49},[{x,0}]}.
     {get_list,{x,0},{x,3},{x,4}}.
 -    {test,is_tuple,{f,58},[{x,3}]}.
 -    {test,test_arity,{f,58},[{x,3},2]}.
 +    {test,is_tuple,{f,46},[{x,3}]}.
 +    {test,test_arity,{f,46},[{x,3},2]}.
     {allocate_heap,2,2,5}.
 -    {get_tuple_element,{x,3},0,{x,0}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {move,{x,2},{y,1}}.
     {move,{x,4},{y,0}}.
 -    {put_list,{x,6},nil,{x,6}}.
 -    {move,{x,1},{x,2}}.
 -    {move,{x,6},{x,1}}.
 +    {move,{x,2},{y,1}}.
 +    {get_tuple_element,{x,3},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {get_tuple_element,{x,3},0,{x,2}}.
     {move,nil,{x,3}}.
 +    {swap,{x,1},{x,2}}.
 +    {swap,{x,0},{x,1}}.
     {line,[{location,"couch_key_tree.erl",253}]}.
 -    {call,4,{f,64}}.
 -    {test,is_tuple,{f,62},[{x,0}]}.
 -    {test,test_arity,{f,62},[{x,0},2]}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {get_tuple_element,{x,0},0,{x,0}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{x,2},{y,1}}.
 +    {call,4,{f,51}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
 +    {get_tuple_element,{x,0},0,{x,1}}.
 +    {move,{y,1},{x,2}}.
 +    {move,{x,0},{y,1}}.
 +    {move,{x,1},{x,0}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",254}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
 -    {move,{y,1},{x,1}}.
 +    {get_tuple_element,{y,1},1,{x,1}}.
     {move,{x,0},{x,2}}.
     {move,{y,0},{x,0}}.
 -    {call_last,3,{f,59},2}.
 -  {label,61}.
 -    {test,is_nil,{f,58},[{x,0}]}.
 +    {call_last,3,{f,47},2}.
 +  {label,49}.
 +    {test,is_nil,{f,46},[{x,0}]}.
     {test_heap,3,3}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,2}}.
 -    {put,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,2},{x,1}]}}.
     return.
 -  {label,62}.
 -    {line,[{location,"couch_key_tree.erl",253}]}.
 -    {badmatch,{x,0}}.


 -{function, get_key_leafs_simple, 4, 64}.
 -  {label,63}.
 +{function, get_key_leafs_simple, 4, 51}.
 +  {label,50}.
     {line,[{location,"couch_key_tree.erl",256}]}.
     {func_info,{atom,couch_key_tree},{atom,get_key_leafs_simple},4}.
 -  {label,64}.
 -    {test,is_nil,{f,65},[{x,2}]}.
 +  {label,51}.
 +    {'%',{var_info,{x,3},[{type,{t_list,any,nil}}]}}.
 +    {test,is_nil,{f,52},[{x,2}]}.
     {move,{literal,{[],[]}},{x,0}}.
     return.
 -  {label,65}.
 -    {test,is_nonempty_list,{f,67},[{x,1}]}.
 +  {label,52}.
 +    {test,is_nonempty_list,{f,54},[{x,1}]}.
     {get_list,{x,1},{x,4},{x,5}}.
 -    {test,is_tuple,{f,63},[{x,4}]}.
 -    {test,test_arity,{f,63},[{x,4},3]}.
 -    {allocate_heap,7,3,6}.
 +    {test,is_tuple,{f,50},[{x,4}]}.
 +    {test,test_arity,{f,50},[{x,4},3]}.
 +    {allocate_heap,6,3,6}.
 +    {move,{x,4},{y,1}}.
 +    {move,{x,5},{y,2}}.
 +    {move,{x,3},{y,3}}.
 +    {move,{x,2},{y,4}}.
 +    {move,{x,0},{y,5}}.
     {get_tuple_element,{x,4},0,{y,0}}.
 -    {get_tuple_element,{x,4},2,{y,1}}.
 -    {move,{x,3},{y,6}}.
 -    {move,{x,2},{y,5}}.
 -    {move,{x,0},{y,4}}.
 -    {move,{x,5},{y,3}}.
 -    {move,{x,4},{y,2}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{y,4}}.
 -    {put,{y,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{y,0}]}}.
     {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",261}]}.
     {call_ext,2,{extfunc,lists,delete,2}}.
 -    {test,is_eq_exact,{f,66},[{x,0},{y,5}]}.
 +    {test,is_eq_exact,{f,53},[{x,0},{y,4}]}.
     {test_heap,2,0}.
 -    {put_list,{y,0},{y,6},{x,0}}.
 +    {put_list,{y,0},{y,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",265}]}.
 -    {gc_bif,'+',{f,0},1,[{y,4},{integer,1}],{x,1}}.
 -    {move,{y,5},{x,2}}.
 +    {gc_bif,'+',{f,0},1,[{y,5},{integer,1}],{x,1}}.
 +    {get_tuple_element,{y,1},2,{x,2}}.
     {move,{x,0},{x,3}}.
     {move,{x,1},{x,0}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{y,3},{y,5}}.
 -    {trim,4,3}.
 +    {move,{x,2},{x,1}}.
 +    {move,{y,4},{x,2}}.
 +    {kill,{y,4}}.
 +    {trim,2,4}.
     {line,[{location,"couch_key_tree.erl",265}]}.
 -    {call,4,{f,64}}.
 -    {test,is_tuple,{f,69},[{x,0}]}.
 -    {test,test_arity,{f,69},[{x,0},2]}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{y,2},{x,3}}.
 +    {call,4,{f,51}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
     {get_tuple_element,{x,0},0,{y,2}}.
 -    {move,{y,0},{x,0}}.
 -    {trim,2,1}.
 +    {get_tuple_element,{x,0},1,{x,2}}.
 +    {move,{y,0},{x,1}}.
 +    {move,{y,1},{x,3}}.
 +    {move,{y,3},{x,0}}.
 +    {kill,{y,3}}.
 +    {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",266}]}.
 -    {call,4,{f,64}}.
 -    {test,is_tuple,{f,68},[{x,0}]}.
 -    {test,test_arity,{f,68},[{x,0},2]}.
 +    {call,4,{f,51}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 +    {move,{x,0},{y,1}}.
     {move,{y,0},{x,0}}.
 -    {move,{x,2},{y,0}}.
 +    {trim,1,1}.
     {line,[{location,"couch_key_tree.erl",267}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {get_tuple_element,{y,0},1,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1}]}}.
     {deallocate,1}.
     return.
 -  {label,66}.
 +  {label,53}.
     {test_heap,2,1}.
 -    {put_list,{y,2},nil,{x,1}}.
 +    {put_list,{y,1},nil,{x,1}}.
     {move,{x,0},{x,2}}.
 -    {move,{y,6},{x,3}}.
 -    {move,{y,4},{x,0}}.
 -    {move,{y,3},{y,5}}.
 -    {trim,4,3}.
 +    {move,{y,3},{x,3}}.
 +    {kill,{y,4}}.
 +    {trim,2,4}.
 +    {move,{y,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",273}]}.
 -    {call,4,{f,73}}.
 -    {test,is_tuple,{f,71},[{x,0}]}.
 -    {test,test_arity,{f,71},[{x,0},2]}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{y,2},{x,3}}.
 +    {call,4,{f,56}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
     {get_tuple_element,{x,0},0,{y,2}}.
 -    {move,{y,0},{x,0}}.
 -    {trim,2,1}.
 +    {get_tuple_element,{x,0},1,{x,2}}.
 +    {move,{y,0},{x,1}}.
 +    {move,{y,1},{x,3}}.
 +    {move,{y,3},{x,0}}.
 +    {kill,{y,3}}.
 +    {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",274}]}.
 -    {call,4,{f,64}}.
 -    {test,is_tuple,{f,70},[{x,0}]}.
 -    {test,test_arity,{f,70},[{x,0},2]}.
 +    {call,4,{f,51}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 +    {move,{x,0},{y,1}}.
     {move,{y,0},{x,0}}.
 -    {move,{x,2},{y,0}}.
 +    {trim,1,1}.
     {line,[{location,"couch_key_tree.erl",275}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {get_tuple_element,{y,0},1,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1}]}}.
     {deallocate,1}.
     return.
 -  {label,67}.
 -    {test,is_nil,{f,63},[{x,1}]}.
 +  {label,54}.
 +    {test,is_nil,{f,50},[{x,1}]}.
     {test_heap,3,3}.
 -    {put_tuple,2,{x,0}}.
 -    {put,nil}.
 -    {put,{x,2}}.
 +    {put_tuple2,{x,0},{list,[nil,{x,2}]}}.
     return.
 -  {label,68}.
 -    {line,[{location,"couch_key_tree.erl",266}]}.
 -    {badmatch,{x,0}}.
 -  {label,69}.
 -    {line,[{location,"couch_key_tree.erl",265}]}.
 -    {badmatch,{x,0}}.
 -  {label,70}.
 -    {line,[{location,"couch_key_tree.erl",274}]}.
 -    {badmatch,{x,0}}.
 -  {label,71}.
 -    {line,[{location,"couch_key_tree.erl",273}]}.
 -    {badmatch,{x,0}}.


 -{function, get_key_leafs_simple2, 4, 73}.
 -  {label,72}.
 +{function, get_key_leafs_simple2, 4, 56}.
 +  {label,55}.
     {line,[{location,"couch_key_tree.erl",278}]}.
     {func_info,{atom,couch_key_tree},{atom,get_key_leafs_simple2},4}.
 -  {label,73}.
 -    {test,is_nonempty_list,{f,75},[{x,1}]}.
 +  {label,56}.
 +    {'%',{var_info,{x,3},[{type,{t_list,any,nil}}]}}.
 +    {test,is_nonempty_list,{f,58},[{x,1}]}.
     {get_list,{x,1},{x,4},{x,5}}.
 -    {test,is_tuple,{f,72},[{x,4}]}.
 -    {test,test_arity,{f,72},[{x,4},3]}.
 -    {get_tuple_element,{x,4},0,{x,6}}.
 -    {get_tuple_element,{x,4},1,{x,7}}.
 -    {get_tuple_element,{x,4},2,{x,8}}.
 -    {test,is_nil,{f,74},[{x,8}]}.
 -    {allocate_heap,5,3,8}.
 -    {move,{x,3},{y,4}}.
 -    {move,{x,0},{y,3}}.
 +    {test,is_tuple,{f,55},[{x,4}]}.
 +    {test,test_arity,{f,55},[{x,4},3]}.
 +    {get_tuple_element,{x,4},0,{x,1}}.
 +    {get_tuple_element,{x,4},1,{x,6}}.
 +    {get_tuple_element,{x,4},2,{x,4}}.
 +    {test,is_nil,{f,57},[{x,4}]}.
 +    {allocate_heap,5,3,7}.
 +    {move,{x,1},{y,0}}.
 +    {move,{x,6},{y,1}}.
     {move,{x,5},{y,2}}.
 -    {move,{x,7},{y,1}}.
 -    {move,{x,6},{y,0}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{y,3}}.
 -    {put,{x,6}}.
 +    {move,{x,3},{y,3}}.
 +    {move,{x,0},{y,4}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1}]}}.
     {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",285}]}.
     {call_ext,2,{extfunc,lists,delete,2}}.
     {move,{x,0},{x,2}}.
     {move,{y,2},{x,1}}.
 -    {move,{y,4},{x,3}}.
 -    {kill,{y,2}}.
 +    {move,{y,3},{x,3}}.
 +    {move,{y,0},{y,2}}.
 +    {trim,1,4}.
     {move,{y,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",286}]}.
 -    {call,4,{f,73}}.
 -    {test,is_tuple,{f,76},[{x,0}]}.
 -    {test,test_arity,{f,76},[{x,0},2]}.
 +    {call,4,{f,56}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
     {test_heap,13,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {put_list,{y,0},{y,4},{x,3}}.
 -    {put_tuple,2,{x,4}}.
 -    {put,{y,3}}.
 -    {put,{x,3}}.
 -    {put_tuple,2,{x,3}}.
 -    {put,{y,1}}.
 -    {put,{x,4}}.
 -    {put_list,{x,3},{x,1},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 -    {deallocate,5}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_list,{y,1},{y,2},{x,2}}.
 +    {put_tuple2,{x,2},{list,[{y,3},{x,2}]}}.
 +    {put_tuple2,{x,2},{list,[{y,0},{x,2}]}}.
 +    {put_list,{x,2},{x,1},{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
 +    {deallocate,4}.
     return.
 -  {label,74}.
 -    {allocate_heap,5,3,9}.
 -    {move,{x,3},{y,4}}.
 -    {move,{x,0},{y,3}}.
 +  {label,57}.
 +    {allocate_heap,5,3,6}.
 +    {move,{x,1},{y,0}}.
 +    {move,{x,4},{y,1}}.
     {move,{x,5},{y,2}}.
 -    {move,{x,8},{y,1}}.
 -    {move,{x,6},{y,0}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{y,3}}.
 -    {put,{x,6}}.
 +    {move,{x,3},{y,3}}.
 +    {move,{x,0},{y,4}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1}]}}.
     {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",291}]}.
     {call_ext,2,{extfunc,lists,delete,2}}.
     {test_heap,2,1}.
 -    {put_list,{y,0},{y,4},{x,1}}.
 +    {put_list,{y,0},{y,3},{x,1}}.
     {line,[{location,"couch_key_tree.erl",293}]}.
 -    {gc_bif,'+',{f,0},2,[{y,3},{integer,1}],{x,4}}.
 +    {gc_bif,'+',{f,0},2,[{y,4},{integer,1}],{x,2}}.
     {move,{x,1},{x,3}}.
     {move,{y,1},{x,1}}.
 -    {move,{x,0},{x,2}}.
 -    {trim,2,3}.
 -    {move,{x,4},{x,0}}.
 +    {swap,{x,0},{x,2}}.
 +    {kill,{y,1}}.
 +    {trim,1,4}.
     {line,[{location,"couch_key_tree.erl",293}]}.
 -    {call,4,{f,73}}.
 -    {test,is_tuple,{f,78},[{x,0}]}.
 -    {test,test_arity,{f,78},[{x,0},2]}.
 +    {call,4,{f,56}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
 +    {get_tuple_element,{x,0},0,{y,0}}.
     {get_tuple_element,{x,0},1,{x,2}}.
 -    {move,{y,0},{x,1}}.
 +    {move,{y,1},{x,1}}.
     {move,{y,2},{x,3}}.
 -    {get_tuple_element,{x,0},0,{y,2}}.
 -    {move,{y,1},{x,0}}.
 -    {trim,2,1}.
 +    {move,{y,3},{x,0}}.
 +    {kill,{y,1}}.
 +    {kill,{y,2}}.
 +    {kill,{y,3}}.
     {line,[{location,"couch_key_tree.erl",294}]}.
 -    {call,4,{f,73}}.
 -    {test,is_tuple,{f,77},[{x,0}]}.
 -    {test,test_arity,{f,77},[{x,0},2]}.
 +    {call,4,{f,56}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,2,true,#{2 => {t_cons,any,any}}}}},
 +             nil}}}}]}}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 +    {move,{x,0},{y,3}}.
     {move,{y,0},{x,0}}.
 -    {move,{x,2},{y,0}}.
 +    {trim,3,1}.
     {line,[{location,"couch_key_tree.erl",295}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {get_tuple_element,{y,0},1,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1}]}}.
     {deallocate,1}.
     return.
 -  {label,75}.
 -    {test,is_nil,{f,72},[{x,1}]}.
 +  {label,58}.
 +    {test,is_nil,{f,55},[{x,1}]}.
     {test_heap,3,3}.
 -    {put_tuple,2,{x,0}}.
 -    {put,nil}.
 -    {put,{x,2}}.
 +    {put_tuple2,{x,0},{list,[nil,{x,2}]}}.
     return.
 -  {label,76}.
 -    {line,[{location,"couch_key_tree.erl",286}]}.
 -    {badmatch,{x,0}}.
 -  {label,77}.
 -    {line,[{location,"couch_key_tree.erl",294}]}.
 -    {badmatch,{x,0}}.
 -  {label,78}.
 -    {line,[{location,"couch_key_tree.erl",293}]}.
 -    {badmatch,{x,0}}.


 -{function, get, 2, 80}.
 -  {label,79}.
 +{function, get, 2, 60}.
 +  {label,59}.
     {line,[{location,"couch_key_tree.erl",297}]}.
     {func_info,{atom,couch_key_tree},{atom,get},2}.
 -  {label,80}.
 +  {label,60}.
     {allocate_zero,1,2}.
     {line,[{location,"couch_key_tree.erl",298}]}.
 -    {call,2,{f,83}}.
 -    {test,is_tuple,{f,81},[{x,0}]}.
 -    {test,test_arity,{f,81},[{x,0},2]}.
 +    {call,2,{f,62}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_list,
 +                               {t_tuple,2,true,
 +                                   #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
 +    {get_tuple_element,{x,0},0,{x,1}}.
     {get_tuple_element,{x,0},1,{y,0}}.
 -    {get_tuple_element,{x,0},0,{x,0}}.
 +    {move,{x,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",301}]}.
 -    {call,1,{f,263}}.
 +    {call,1,{f,234}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_list,any,nil}}}}},
 +                     nil}}]}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{y,0}]}}.
     {deallocate,1}.
     return.
 -  {label,81}.
 -    {line,[{location,"couch_key_tree.erl",298}]}.
 -    {badmatch,{x,0}}.


 -{function, get_full_key_paths, 2, 83}.
 -  {label,82}.
 +{function, get_full_key_paths, 2, 62}.
 +  {label,61}.
     {line,[{location,"couch_key_tree.erl",305}]}.
     {func_info,{atom,couch_key_tree},{atom,get_full_key_paths},2}.
 -  {label,83}.
 +  {label,62}.
     {move,nil,{x,2}}.
 -    {call_only,3,{f,85}}.
 +    {call_only,3,{f,64}}.


 -{function, get_full_key_paths, 3, 85}.
 -  {label,84}.
 +{function, get_full_key_paths, 3, 64}.
 +  {label,63}.
     {line,[{location,"couch_key_tree.erl",308}]}.
     {func_info,{atom,couch_key_tree},{atom,get_full_key_paths},3}.
 -  {label,85}.
 -    {test,is_nil,{f,86},[{x,1}]}.
 +  {label,64}.
 +    {'%',
 +        {var_info,
 +            {x,2},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                     nil}}]}}.
 +    {test,is_nil,{f,65},[{x,1}]}.
     {test_heap,3,3}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,2}}.
 -    {put,nil}.
 +    {put_tuple2,{x,0},{list,[{x,2},nil]}}.
     return.
 -  {label,86}.
 -    {test,is_nonempty_list,{f,87},[{x,0}]}.
 +  {label,65}.
 +    {test,is_nonempty_list,{f,66},[{x,0}]}.
     {get_list,{x,0},{x,3},{x,4}}.
 -    {test,is_tuple,{f,84},[{x,3}]}.
 -    {test,test_arity,{f,84},[{x,3},2]}.
 +    {test,is_tuple,{f,63},[{x,3}]}.
 +    {test,test_arity,{f,63},[{x,3},2]}.
     {allocate_heap,2,2,5}.
 -    {get_tuple_element,{x,3},0,{x,0}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {move,{x,2},{y,1}}.
     {move,{x,4},{y,0}}.
 -    {put_list,{x,6},nil,{x,6}}.
 -    {move,{x,1},{x,2}}.
 -    {move,{x,6},{x,1}}.
 +    {move,{x,2},{y,1}}.
 +    {get_tuple_element,{x,3},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {get_tuple_element,{x,3},0,{x,2}}.
     {move,nil,{x,3}}.
 +    {swap,{x,1},{x,2}}.
 +    {swap,{x,0},{x,1}}.
     {line,[{location,"couch_key_tree.erl",313}]}.
 -    {call,4,{f,90}}.
 -    {test,is_tuple,{f,88},[{x,0}]}.
 -    {test,test_arity,{f,88},[{x,0},2]}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {get_tuple_element,{x,0},0,{x,0}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{x,2},{y,1}}.
 +    {call,4,{f,68}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_list,
 +                               {t_tuple,2,true,
 +                                   #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
 +    {get_tuple_element,{x,0},0,{x,1}}.
 +    {move,{y,1},{x,2}}.
 +    {move,{x,0},{y,1}}.
 +    {move,{x,1},{x,0}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",314}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
 -    {move,{y,1},{x,1}}.
 +    {get_tuple_element,{y,1},1,{x,1}}.
     {move,{x,0},{x,2}}.
     {move,{y,0},{x,0}}.
 -    {call_last,3,{f,85},2}.
 -  {label,87}.
 -    {test,is_nil,{f,84},[{x,0}]}.
 +    {call_last,3,{f,64},2}.
 +  {label,66}.
 +    {test,is_nil,{f,63},[{x,0}]}.
     {test_heap,3,3}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,2}}.
 -    {put,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,2},{x,1}]}}.
     return.
 -  {label,88}.
 -    {line,[{location,"couch_key_tree.erl",313}]}.
 -    {badmatch,{x,0}}.


 -{function, get_full_key_paths, 4, 90}.
 -  {label,89}.
 +{function, get_full_key_paths, 4, 68}.
 +  {label,67}.
     {line,[{location,"couch_key_tree.erl",316}]}.
     {func_info,{atom,couch_key_tree},{atom,get_full_key_paths},4}.
 -  {label,90}.
 -    {test,is_nil,{f,91},[{x,2}]}.
 +  {label,68}.
 +    {'%',{var_info,{x,3},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {test,is_nil,{f,69},[{x,2}]}.
     {move,{literal,{[],[]}},{x,0}}.
     return.
 -  {label,91}.
 -    {test,is_nonempty_list,{f,94},[{x,1}]}.
 +  {label,69}.
 +    {test,is_nonempty_list,{f,72},[{x,1}]}.
     {get_list,{x,1},{x,4},{x,5}}.
 -    {test,is_tuple,{f,89},[{x,4}]}.
 -    {test,test_arity,{f,89},[{x,4},3]}.
 -    {allocate_heap,7,5,6}.
 +    {test,is_tuple,{f,67},[{x,4}]}.
 +    {test,test_arity,{f,67},[{x,4},3]}.
 +    {allocate_heap,6,5,6}.
 +    {move,{x,4},{y,1}}.
 +    {move,{x,5},{y,2}}.
 +    {move,{x,3},{y,3}}.
 +    {move,{x,2},{y,4}}.
 +    {move,{x,0},{y,5}}.
     {get_tuple_element,{x,4},0,{y,0}}.
 -    {get_tuple_element,{x,4},1,{y,1}}.
 -    {get_tuple_element,{x,4},2,{y,2}}.
 -    {move,{x,3},{y,6}}.
 -    {move,{x,2},{y,5}}.
 -    {move,{x,0},{y,4}}.
 -    {move,{x,5},{y,3}}.
 -    {put_tuple,2,{x,4}}.
 -    {put,{y,4}}.
 -    {put,{y,0}}.
 -    {put_list,{x,4},nil,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{y,0}]}}.
 +    {put_list,{x,0},nil,{x,1}}.
     {move,{x,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",321}]}.
     {call_ext,2,{extfunc,erlang,'--',2}}.
     {line,[{location,"couch_key_tree.erl",323}]}.
     {gc_bif,length,{f,0},1,[{x,0}],{x,1}}.
     {line,[{location,"couch_key_tree.erl",323}]}.
 -    {gc_bif,length,{f,0},2,[{y,5}],{x,2}}.
 -    {move,{x,0},{y,5}}.
 -    {test,is_eq_exact,{f,92},[{x,1},{x,2}]}.
 -    {move,nil,{x,0}}.
 -    {jump,{f,93}}.
 -  {label,92}.
 -    {test_heap,10,0}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,0}}.
 -    {put,{y,1}}.
 -    {put_list,{x,1},{y,6},{x,1}}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{y,4}}.
 -    {put,{x,1}}.
 -    {put_list,{x,2},nil,{x,0}}.
 -  {label,93}.
 +    {gc_bif,length,{f,0},2,[{y,4}],{x,2}}.
 +    {get_tuple_element,{y,1},1,{x,3}}.
 +    {test,is_eq_exact,{f,70},[{x,1},{x,2}]}.
 +    {move,nil,{y,4}}.
 +    {jump,{f,71}}.
 +  {label,70}.
 +    {test_heap,10,4}.
 +    {put_tuple2,{x,1},{list,[{y,0},{x,3}]}}.
 +    {put_list,{x,1},{y,3},{x,1}}.
 +    {put_tuple2,{x,1},{list,[{y,5},{x,1}]}}.
 +    {put_list,{x,1},nil,{x,1}}.
 +    {move,{x,1},{y,4}}.
 +  {label,71}.
     {line,[{location,"couch_key_tree.erl",331}]}.
 -    {gc_bif,'+',{f,0},1,[{y,4},{integer,1}],{x,1}}.
 -    {test_heap,5,2}.
 -    {put_tuple,2,{x,4}}.
 -    {put,{y,0}}.
 -    {put,{y,1}}.
 -    {move,{x,0},{y,1}}.
 -    {put_list,{x,4},{y,6},{x,3}}.
 -    {move,{y,5},{x,2}}.
 -    {move,{x,1},{x,0}}.
 -    {move,{y,2},{x,1}}.
 -    {move,{y,1},{y,5}}.
 -    {trim,3,4}.
 +    {gc_bif,'+',{f,0},4,[{y,5},{integer,1}],{x,1}}.
 +    {test_heap,5,4}.
 +    {put_tuple2,{x,2},{list,[{y,0},{x,3}]}}.
 +    {put_list,{x,2},{y,3},{x,3}}.
 +    {get_tuple_element,{y,1},2,{x,2}}.
 +    {swap,{x,2},{x,1}}.
 +    {swap,{x,0},{x,2}}.
 +    {kill,{y,1}}.
 +    {trim,1,5}.
     {line,[{location,"couch_key_tree.erl",331}]}.
 -    {call,4,{f,90}}.
 -    {test,is_tuple,{f,96},[{x,0}]}.
 -    {test,test_arity,{f,96},[{x,0},2]}.
 +    {call,4,{f,68}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_list,
 +                               {t_tuple,2,true,
 +                                   #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
 +    {get_tuple_element,{x,0},0,{y,0}}.
     {get_tuple_element,{x,0},1,{x,2}}.
 -    {move,{y,0},{x,1}}.
 -    {move,{y,3},{x,3}}.
 -    {get_tuple_element,{x,0},0,{y,3}}.
 -    {move,{y,1},{x,0}}.
 -    {trim,2,2}.
 +    {move,{y,1},{x,1}}.
 +    {move,{y,2},{x,3}}.
 +    {move,{y,4},{x,0}}.
 +    {kill,{y,1}}.
 +    {kill,{y,2}}.
 +    {kill,{y,4}}.
     {line,[{location,"couch_key_tree.erl",334}]}.
 -    {call,4,{f,90}}.
 -    {test,is_tuple,{f,95},[{x,0}]}.
 -    {test,test_arity,{f,95},[{x,0},2]}.
 +    {call,4,{f,68}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_list,
 +                               {t_tuple,2,true,
 +                                   #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {move,{y,1},{x,0}}.
 -    {move,{x,2},{y,1}}.
 +    {move,{x,0},{y,4}}.
 +    {move,{y,0},{x,0}}.
 +    {trim,3,2}.
     {line,[{location,"couch_key_tree.erl",335}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {move,{x,0},{x,1}}.
 @@ -1167,1012 +1241,1146 @@
     {line,[{location,"couch_key_tree.erl",335}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 +    {get_tuple_element,{y,0},1,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1}]}}.
     {deallocate,1}.
     return.
 -  {label,94}.
 -    {test,is_nil,{f,89},[{x,1}]}.
 +  {label,72}.
 +    {test,is_nil,{f,67},[{x,1}]}.
     {test_heap,3,3}.
 -    {put_tuple,2,{x,0}}.
 -    {put,nil}.
 -    {put,{x,2}}.
 +    {put_tuple2,{x,0},{list,[nil,{x,2}]}}.
     return.
 -  {label,95}.
 -    {line,[{location,"couch_key_tree.erl",334}]}.
 -    {badmatch,{x,0}}.
 -  {label,96}.
 -    {line,[{location,"couch_key_tree.erl",331}]}.
 -    {badmatch,{x,0}}.


 -{function, get_all_leafs_full, 1, 98}.
 -  {label,97}.
 +{function, get_all_leafs_full, 1, 74}.
 +  {label,73}.
     {line,[{location,"couch_key_tree.erl",337}]}.
     {func_info,{atom,couch_key_tree},{atom,get_all_leafs_full},1}.
 -  {label,98}.
 +  {label,74}.
     {move,nil,{x,1}}.
 -    {call_only,2,{f,100}}.
 +    {call_only,2,{f,76}}.


 -{function, get_all_leafs_full, 2, 100}.
 -  {label,99}.
 +{function, get_all_leafs_full, 2, 76}.
 +  {label,75}.
     {line,[{location,"couch_key_tree.erl",340}]}.
     {func_info,{atom,couch_key_tree},{atom,get_all_leafs_full},2}.
 -  {label,100}.
 -    {test,is_nonempty_list,{f,101},[{x,0}]}.
 +  {label,76}.
 +    {'%',
 +        {var_info,
 +            {x,1},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
 +    {test,is_nonempty_list,{f,77},[{x,0}]}.
     {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,99},[{x,2}]}.
 -    {test,test_arity,{f,99},[{x,2},2]}.
 +    {test,is_tuple,{f,75},[{x,2}]}.
 +    {test,test_arity,{f,75},[{x,2},2]}.
     {allocate_heap,2,2,4}.
 -    {get_tuple_element,{x,2},0,{x,0}}.
 -    {get_tuple_element,{x,2},1,{x,5}}.
 -    {move,{x,1},{y,1}}.
     {move,{x,3},{y,0}}.
 -    {put_list,{x,5},nil,{x,1}}.
 +    {move,{x,1},{y,1}}.
 +    {get_tuple_element,{x,2},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,1}}.
 +    {get_tuple_element,{x,2},0,{x,0}}.
     {move,nil,{x,2}}.
     {line,[{location,"couch_key_tree.erl",343}]}.
 -    {call,3,{f,103}}.
 +    {call,3,{f,79}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
     {move,{y,1},{x,1}}.
     {kill,{y,1}}.
     {line,[{location,"couch_key_tree.erl",343}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
 -    {call_last,2,{f,100},2}.
 -  {label,101}.
 -    {test,is_nil,{f,99},[{x,0}]}.
 +    {call_last,2,{f,76},2}.
 +  {label,77}.
 +    {test,is_nil,{f,75},[{x,0}]}.
     {move,{x,1},{x,0}}.
     return.


 -{function, get_all_leafs_full_simple, 3, 103}.
 -  {label,102}.
 +{function, get_all_leafs_full_simple, 3, 79}.
 +  {label,78}.
     {line,[{location,"couch_key_tree.erl",345}]}.
     {func_info,{atom,couch_key_tree},{atom,get_all_leafs_full_simple},3}.
 -  {label,103}.
 -    {test,is_nonempty_list,{f,105},[{x,1}]}.
 +  {label,79}.
 +    {'%',{var_info,{x,2},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {test,is_nonempty_list,{f,81},[{x,1}]}.
     {get_list,{x,1},{x,3},{x,4}}.
 -    {test,is_tuple,{f,102},[{x,3}]}.
 -    {test,test_arity,{f,102},[{x,3},3]}.
 -    {get_tuple_element,{x,3},0,{x,5}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {get_tuple_element,{x,3},2,{x,7}}.
 -    {test,is_nil,{f,104},[{x,7}]}.
 -    {allocate,4,7}.
 -    {move,{x,4},{x,1}}.
 -    {move,{x,6},{y,0}}.
 +    {test,is_tuple,{f,78},[{x,3}]}.
 +    {test,test_arity,{f,78},[{x,3},3]}.
 +    {get_tuple_element,{x,3},0,{x,1}}.
 +    {get_tuple_element,{x,3},1,{x,5}}.
 +    {get_tuple_element,{x,3},2,{x,3}}.
 +    {test,is_nil,{f,80},[{x,3}]}.
 +    {allocate,4,6}.
 +    {move,{x,1},{y,0}}.
     {move,{x,5},{y,1}}.
     {move,{x,2},{y,2}}.
     {move,{x,0},{y,3}}.
 +    {move,{x,4},{x,1}}.
     {line,[{location,"couch_key_tree.erl",348}]}.
 -    {call,3,{f,103}}.
 +    {call,3,{f,79}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
     {test_heap,10,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 +    {put_tuple2,{x,1},{list,[{y,0},{y,1}]}}.
     {put_list,{x,1},{y,2},{x,1}}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{y,3}}.
 -    {put,{x,1}}.
 -    {put_list,{x,2},{x,0},{x,0}}.
 +    {put_tuple2,{x,1},{list,[{y,3},{x,1}]}}.
 +    {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,4}.
     return.
 -  {label,104}.
 -    {allocate_zero,3,8}.
 +  {label,80}.
     {line,[{location,"couch_key_tree.erl",350}]}.
 -    {gc_bif,'+',{f,0},8,[{x,0},{integer,1}],{x,1}}.
 -    {test_heap,5,8}.
 -    {move,{x,2},{y,2}}.
 -    {move,{x,0},{y,1}}.
 +    {gc_bif,'+',{f,0},6,[{x,0},{integer,1}],{x,6}}.
 +    {allocate_heap,3,5,7}.
     {move,{x,4},{y,0}}.
 -    {put_tuple,2,{x,3}}.
 -    {put,{x,5}}.
 -    {put,{x,6}}.
 -    {put_list,{x,3},{y,2},{x,2}}.
 -    {move,{x,1},{x,0}}.
 -    {move,{x,7},{x,1}}.
 +    {move,{x,2},{y,1}}.
 +    {move,{x,0},{y,2}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,5}]}}.
 +    {put_list,{x,0},{x,2},{x,2}}.
 +    {move,{x,3},{x,1}}.
 +    {move,{x,6},{x,0}}.
     {line,[{location,"couch_key_tree.erl",350}]}.
 -    {call,3,{f,103}}.
 -    {move,{x,0},{x,3}}.
 -    {move,{y,0},{x,1}}.
 -    {move,{y,2},{x,2}}.
 -    {move,{x,3},{y,2}}.
 -    {move,{y,1},{x,0}}.
 +    {call,3,{f,79}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
 +    {move,{y,0},{x,2}}.
 +    {move,{y,1},{x,3}}.
 +    {swap,{y,2},{x,0}}.
 +    {move,{x,2},{x,1}}.
 +    {move,{x,3},{x,2}}.
     {trim,2,1}.
     {line,[{location,"couch_key_tree.erl",351}]}.
 -    {call,3,{f,103}}.
 +    {call,3,{f,79}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",350}]}.
     {call_ext_last,2,{extfunc,erlang,'++',2},1}.
 -  {label,105}.
 -    {test,is_nil,{f,102},[{x,1}]}.
 +  {label,81}.
 +    {test,is_nil,{f,78},[{x,1}]}.
     {move,nil,{x,0}}.
     return.


 -{function, get_all_leafs, 1, 107}.
 -  {label,106}.
 +{function, get_all_leafs, 1, 83}.
 +  {label,82}.
     {line,[{location,"couch_key_tree.erl",353}]}.
     {func_info,{atom,couch_key_tree},{atom,get_all_leafs},1}.
 -  {label,107}.
 +  {label,83}.
     {move,nil,{x,1}}.
 -    {call_only,2,{f,109}}.
 +    {call_only,2,{f,85}}.


 -{function, get_all_leafs, 2, 109}.
 -  {label,108}.
 +{function, get_all_leafs, 2, 85}.
 +  {label,84}.
     {line,[{location,"couch_key_tree.erl",356}]}.
     {func_info,{atom,couch_key_tree},{atom,get_all_leafs},2}.
 -  {label,109}.
 -    {test,is_nonempty_list,{f,110},[{x,0}]}.
 +  {label,85}.
 +    {'%',
 +        {var_info,
 +            {x,1},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_cons,any,nil}}}}},
 +                     nil}}]}}.
 +    {test,is_nonempty_list,{f,86},[{x,0}]}.
     {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,108},[{x,2}]}.
 -    {test,test_arity,{f,108},[{x,2},2]}.
 +    {test,is_tuple,{f,84},[{x,2}]}.
 +    {test,test_arity,{f,84},[{x,2},2]}.
     {allocate_heap,2,2,4}.
 -    {get_tuple_element,{x,2},0,{x,0}}.
 -    {get_tuple_element,{x,2},1,{x,5}}.
 -    {move,{x,1},{y,1}}.
     {move,{x,3},{y,0}}.
 -    {put_list,{x,5},nil,{x,1}}.
 +    {move,{x,1},{y,1}}.
 +    {get_tuple_element,{x,2},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,1}}.
 +    {get_tuple_element,{x,2},0,{x,0}}.
     {move,nil,{x,2}}.
     {line,[{location,"couch_key_tree.erl",359}]}.
 -    {call,3,{f,112}}.
 +    {call,3,{f,88}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_cons,any,nil}}}}},
 +                     nil}}]}}.
     {move,{y,1},{x,1}}.
     {kill,{y,1}}.
     {line,[{location,"couch_key_tree.erl",359}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
 -    {call_last,2,{f,109},2}.
 -  {label,110}.
 -    {test,is_nil,{f,108},[{x,0}]}.
 +    {call_last,2,{f,85},2}.
 +  {label,86}.
 +    {test,is_nil,{f,84},[{x,0}]}.
     {move,{x,1},{x,0}}.
     return.


 -{function, get_all_leafs_simple, 3, 112}.
 -  {label,111}.
 +{function, get_all_leafs_simple, 3, 88}.
 +  {label,87}.
     {line,[{location,"couch_key_tree.erl",361}]}.
     {func_info,{atom,couch_key_tree},{atom,get_all_leafs_simple},3}.
 -  {label,112}.
 -    {test,is_nonempty_list,{f,114},[{x,1}]}.
 +  {label,88}.
 +    {'%',{var_info,{x,2},[{type,{t_list,any,nil}}]}}.
 +    {test,is_nonempty_list,{f,90},[{x,1}]}.
     {get_list,{x,1},{x,3},{x,4}}.
 -    {test,is_tuple,{f,111},[{x,3}]}.
 -    {test,test_arity,{f,111},[{x,3},3]}.
 -    {get_tuple_element,{x,3},0,{x,5}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {get_tuple_element,{x,3},2,{x,7}}.
 -    {test,is_nil,{f,113},[{x,7}]}.
 -    {allocate,4,7}.
 -    {move,{x,4},{x,1}}.
 -    {move,{x,2},{y,0}}.
 +    {test,is_tuple,{f,87},[{x,3}]}.
 +    {test,test_arity,{f,87},[{x,3},3]}.
 +    {get_tuple_element,{x,3},0,{x,1}}.
 +    {get_tuple_element,{x,3},1,{x,5}}.
 +    {get_tuple_element,{x,3},2,{x,3}}.
 +    {test,is_nil,{f,89},[{x,3}]}.
 +    {allocate,4,6}.
 +    {move,{x,1},{y,0}}.
     {move,{x,5},{y,1}}.
 -    {move,{x,0},{y,2}}.
 -    {move,{x,6},{y,3}}.
 +    {move,{x,2},{y,2}}.
 +    {move,{x,0},{y,3}}.
 +    {move,{x,4},{x,1}}.
     {line,[{location,"couch_key_tree.erl",364}]}.
 -    {call,3,{f,112}}.
 +    {call,3,{f,88}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_cons,any,nil}}}}},
 +                     nil}}]}}.
     {test_heap,10,1}.
 -    {put_list,{y,1},{y,0},{x,1}}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{y,2}}.
 -    {put,{x,1}}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,3}}.
 -    {put,{x,2}}.
 +    {put_list,{y,0},{y,2},{x,1}}.
 +    {put_tuple2,{x,1},{list,[{y,3},{x,1}]}}.
 +    {put_tuple2,{x,1},{list,[{y,1},{x,1}]}}.
     {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,4}.
     return.
 -  {label,113}.
 -    {allocate_zero,3,8}.
 +  {label,89}.
     {line,[{location,"couch_key_tree.erl",366}]}.
 -    {gc_bif,'+',{f,0},8,[{x,0},{integer,1}],{x,1}}.
 -    {test_heap,2,8}.
 -    {move,{x,2},{y,2}}.
 -    {move,{x,0},{y,1}}.
 +    {gc_bif,'+',{f,0},5,[{x,0},{integer,1}],{x,5}}.
 +    {allocate_heap,3,2,6}.
     {move,{x,4},{y,0}}.
 -    {put_list,{x,5},{y,2},{x,2}}.
 -    {move,{x,1},{x,0}}.
 -    {move,{x,7},{x,1}}.
 +    {move,{x,2},{y,1}}.
 +    {move,{x,0},{y,2}}.
 +    {put_list,{x,1},{x,2},{x,2}}.
 +    {move,{x,3},{x,1}}.
 +    {move,{x,5},{x,0}}.
     {line,[{location,"couch_key_tree.erl",366}]}.
 -    {call,3,{f,112}}.
 -    {move,{x,0},{x,3}}.
 -    {move,{y,0},{x,1}}.
 -    {move,{y,2},{x,2}}.
 -    {move,{x,3},{y,2}}.
 -    {move,{y,1},{x,0}}.
 +    {call,3,{f,88}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_cons,any,nil}}}}},
 +                     nil}}]}}.
 +    {move,{y,0},{x,2}}.
 +    {move,{y,1},{x,3}}.
 +    {swap,{y,2},{x,0}}.
 +    {move,{x,2},{x,1}}.
 +    {move,{x,3},{x,2}}.
     {trim,2,1}.
     {line,[{location,"couch_key_tree.erl",367}]}.
 -    {call,3,{f,112}}.
 +    {call,3,{f,88}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_cons,any,nil}}}}},
 +                     nil}}]}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",366}]}.
     {call_ext_last,2,{extfunc,erlang,'++',2},1}.
 -  {label,114}.
 -    {test,is_nil,{f,111},[{x,1}]}.
 +  {label,90}.
 +    {test,is_nil,{f,87},[{x,1}]}.
     {move,nil,{x,0}}.
     return.


 -{function, count_leafs, 1, 116}.
 -  {label,115}.
 +{function, count_leafs, 1, 92}.
 +  {label,91}.
     {line,[{location,"couch_key_tree.erl",369}]}.
     {func_info,{atom,couch_key_tree},{atom,count_leafs},1}.
 -  {label,116}.
 -    {test,is_nonempty_list,{f,117},[{x,0}]}.
 +  {label,92}.
 +    {test,is_nonempty_list,{f,93},[{x,0}]}.
     {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_tuple,{f,115},[{x,1}]}.
 -    {test,test_arity,{f,115},[{x,1},2]}.
 +    {test,is_tuple,{f,91},[{x,1}]}.
 +    {test,test_arity,{f,91},[{x,1},2]}.
     {allocate_heap,1,2,3}.
 -    {get_tuple_element,{x,1},1,{x,3}}.
     {move,{x,2},{y,0}}.
 -    {put_list,{x,3},nil,{x,0}}.
 +    {get_tuple_element,{x,1},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,0}}.
     {line,[{location,"couch_key_tree.erl",372}]}.
 -    {call,1,{f,119}}.
 -    {move,{x,0},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,1},{y,0}}.
 +    {call,1,{f,95}}.
 +    {'%',{var_info,{x,0},[{type,{t_integer,any}}]}}.
 +    {swap,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",372}]}.
 -    {call,1,{f,116}}.
 +    {call,1,{f,92}}.
 +    {'%',{var_info,{x,0},[{type,{t_integer,any}}]}}.
     {line,[{location,"couch_key_tree.erl",372}]}.
     {gc_bif,'+',{f,0},1,[{y,0},{x,0}],{x,0}}.
     {deallocate,1}.
     return.
 -  {label,117}.
 -    {test,is_nil,{f,115},[{x,0}]}.
 +  {label,93}.
 +    {test,is_nil,{f,91},[{x,0}]}.
     {move,{integer,0},{x,0}}.
     return.


 -{function, count_leafs_simple, 1, 119}.
 -  {label,118}.
 +{function, count_leafs_simple, 1, 95}.
 +  {label,94}.
     {line,[{location,"couch_key_tree.erl",374}]}.
     {func_info,{atom,couch_key_tree},{atom,count_leafs_simple},1}.
 -  {label,119}.
 -    {test,is_nonempty_list,{f,121},[{x,0}]}.
 +  {label,95}.
 +    {test,is_nonempty_list,{f,97},[{x,0}]}.
     {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_tuple,{f,118},[{x,1}]}.
 -    {test,test_arity,{f,118},[{x,1},3]}.
 -    {get_tuple_element,{x,1},2,{x,3}}.
 -    {test,is_nil,{f,120},[{x,3}]}.
 +    {test,is_tuple,{f,94},[{x,1}]}.
 +    {test,test_arity,{f,94},[{x,1},3]}.
 +    {get_tuple_element,{x,1},2,{x,0}}.
 +    {test,is_nil,{f,96},[{x,0}]}.
     {allocate,0,3}.
     {move,{x,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",377}]}.
 -    {call,1,{f,119}}.
 +    {call,1,{f,95}}.
 +    {'%',{var_info,{x,0},[{type,{t_integer,any}}]}}.
     {line,[{location,"couch_key_tree.erl",377}]}.
 -    {gc_bif,'+',{f,0},1,[{integer,1},{x,0}],{x,0}}.
 +    {gc_bif,'+',{f,0},1,[{x,0},{integer,1}],{x,0}}.
     {deallocate,0}.
     return.
 -  {label,120}.
 -    {allocate,1,4}.
 +  {label,96}.
 +    {allocate,1,3}.
     {move,{x,2},{y,0}}.
 -    {move,{x,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",379}]}.
 -    {call,1,{f,119}}.
 -    {move,{x,0},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,1},{y,0}}.
 +    {call,1,{f,95}}.
 +    {'%',{var_info,{x,0},[{type,{t_integer,any}}]}}.
 +    {swap,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",379}]}.
 -    {call,1,{f,119}}.
 +    {call,1,{f,95}}.
 +    {'%',{var_info,{x,0},[{type,{t_integer,any}}]}}.
     {line,[{location,"couch_key_tree.erl",379}]}.
     {gc_bif,'+',{f,0},1,[{y,0},{x,0}],{x,0}}.
     {deallocate,1}.
     return.
 -  {label,121}.
 -    {test,is_nil,{f,118},[{x,0}]}.
 +  {label,97}.
 +    {test,is_nil,{f,94},[{x,0}]}.
     {move,{integer,0},{x,0}}.
     return.


 -{function, fold, 3, 123}.
 -  {label,122}.
 +{function, fold, 3, 99}.
 +  {label,98}.
     {line,[{location,"couch_key_tree.erl",381}]}.
     {func_info,{atom,couch_key_tree},{atom,fold},3}.
 -  {label,123}.
 -    {test,is_nonempty_list,{f,124},[{x,2}]}.
 +  {label,99}.
 +    {test,is_nonempty_list,{f,100},[{x,2}]}.
     {get_list,{x,2},{x,3},{x,4}}.
 -    {test,is_tuple,{f,122},[{x,3}]}.
 -    {test,test_arity,{f,122},[{x,3},2]}.
 +    {test,is_tuple,{f,98},[{x,3}]}.
 +    {test,test_arity,{f,98},[{x,3},2]}.
     {allocate_heap,2,2,5}.
 -    {get_tuple_element,{x,3},0,{x,2}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {move,{x,0},{y,1}}.
     {move,{x,4},{y,0}}.
 -    {put_list,{x,6},nil,{x,3}}.
 +    {move,{x,0},{y,1}}.
 +    {get_tuple_element,{x,3},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {get_tuple_element,{x,3},0,{x,2}}.
 +    {move,{x,0},{x,3}}.
 +    {move,{y,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",384}]}.
 -    {call,4,{f,126}}.
 +    {call,4,{f,102}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,2}}.
     {move,{y,1},{x,0}}.
 -    {call_last,3,{f,123},2}.
 -  {label,124}.
 -    {test,is_nil,{f,122},[{x,2}]}.
 +    {call_last,3,{f,99},2}.
 +  {label,100}.
 +    {test,is_nil,{f,98},[{x,2}]}.
     {move,{x,1},{x,0}}.
     return.


 -{function, fold_simple, 4, 126}.
 -  {label,125}.
 +{function, fold_simple, 4, 102}.
 +  {label,101}.
     {line,[{location,"couch_key_tree.erl",387}]}.
     {func_info,{atom,couch_key_tree},{atom,fold_simple},4}.
 -  {label,126}.
 -    {test,is_nonempty_list,{f,129},[{x,3}]}.
 +  {label,102}.
 +    {test,is_nonempty_list,{f,105},[{x,3}]}.
     {get_list,{x,3},{x,4},{x,5}}.
 -    {test,is_tuple,{f,125},[{x,4}]}.
 -    {test,test_arity,{f,125},[{x,4},3]}.
 -    {allocate,7,6}.
 -    {get_tuple_element,{x,4},0,{y,0}}.
 -    {get_tuple_element,{x,4},1,{y,2}}.
 -    {get_tuple_element,{x,4},2,{x,8}}.
 -    {move,{x,1},{y,1}}.
 -    {move,{x,8},{y,3}}.
 -    {move,{x,2},{y,4}}.
 -    {move,{x,0},{y,5}}.
 -    {move,{x,5},{y,6}}.
 -    {test,is_nil,{f,127},[{x,8}]}.
 -    {move,{atom,leaf},{x,0}}.
 -    {jump,{f,128}}.
 -  {label,127}.
 -    {move,{atom,branch},{x,0}}.
 -  {label,128}.
 -    {test_heap,3,1}.
 -    {put_tuple,2,{x,5}}.
 -    {put,{y,4}}.
 -    {put,{y,0}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,1},{x,3}}.
 -    {move,{y,2},{x,1}}.
 -    {move,{y,5},{x,4}}.
 -    {trim,3,4}.
 -    {move,{x,5},{x,0}}.
 +    {test,is_tuple,{f,101},[{x,4}]}.
 +    {test,test_arity,{f,101},[{x,4},3]}.
 +    {allocate,4,6}.
 +    {move,{x,5},{y,1}}.
 +    {move,{x,2},{y,2}}.
 +    {move,{x,0},{y,3}}.
 +    {get_tuple_element,{x,4},2,{y,0}}.
 +    {test,is_nil,{f,103},[{y,0}]}.
 +    {move,{atom,leaf},{x,2}}.
 +    {jump,{f,104}}.
 +  {label,103}.
 +    {move,{atom,branch},{x,2}}.
 +  {label,104}.
 +    {test_heap,3,5}.
 +    {get_tuple_element,{x,4},0,{x,0}}.
 +    {put_tuple2,{x,0},{list,[{y,2},{x,0}]}}.
 +    {get_tuple_element,{x,4},1,{x,3}}.
 +    {move,{y,3},{x,4}}.
 +    {swap,{x,1},{x,3}}.
     {line,[{location,"couch_key_tree.erl",395}]}.
     {call_fun,4}.
     {line,[{location,"couch_key_tree.erl",396}]}.
 -    {gc_bif,'+',{f,0},1,[{y,1},{integer,1}],{x,2}}.
 +    {gc_bif,'+',{f,0},1,[{y,2},{integer,1}],{x,2}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,3}}.
     {trim,1,3}.
 -    {move,{y,1},{x,0}}.
 +    {move,{y,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",396}]}.
 -    {call,4,{f,126}}.
 -    {move,{y,0},{x,2}}.
 +    {call,4,{f,102}}.
 +    {move,{y,1},{x,2}}.
     {move,{x,0},{x,1}}.
 -    {move,{y,2},{x,3}}.
 -    {move,{y,1},{x,0}}.
 -    {call_last,4,{f,126},3}.
 -  {label,129}.
 -    {test,is_nil,{f,125},[{x,3}]}.
 +    {move,{y,0},{x,3}}.
 +    {move,{y,2},{x,0}}.
 +    {call_last,4,{f,102},3}.
 +  {label,105}.
 +    {test,is_nil,{f,101},[{x,3}]}.
     {move,{x,1},{x,0}}.
     return.


 -{function, map, 2, 131}.
 -  {label,130}.
 +{function, map, 2, 107}.
 +  {label,106}.
     {line,[{location,"couch_key_tree.erl",399}]}.
     {func_info,{atom,couch_key_tree},{atom,map},2}.
 -  {label,131}.
 -    {test,is_nonempty_list,{f,134},[{x,1}]}.
 +  {label,107}.
 +    {test,is_nonempty_list,{f,110},[{x,1}]}.
     {get_list,{x,1},{x,2},{x,3}}.
 -    {test,is_tuple,{f,130},[{x,2}]}.
 -    {test,test_arity,{f,130},[{x,2},2]}.
 +    {test,is_tuple,{f,106},[{x,2}]}.
 +    {test,test_arity,{f,106},[{x,2},2]}.
     {allocate,4,4}.
 -    {get_tuple_element,{x,2},0,{y,3}}.
 -    {get_tuple_element,{x,2},1,{y,2}}.
 +    {init,{y,0}}.
 +    {move,{x,2},{y,1}}.
 +    {move,{x,3},{y,2}}.
 +    {move,{x,0},{y,3}}.
     {move,{atom,arity},{x,1}}.
 -    {move,{x,0},{y,0}}.
 -    {move,{x,3},{y,1}}.
     {line,[{location,"couch_key_tree.erl",402}]}.
     {call_ext,2,{extfunc,erlang,fun_info,2}}.
 -    {test,is_tagged_tuple,{f,137},[{x,0},2,{atom,arity}]}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {test,is_integer,{f,137},[{x,2}]}.
 -    {select_val,{x,2},
 -                {f,137},
 -                {list,[{integer,3},{f,132},{integer,2},{f,133}]}}.
 -  {label,132}.
 +    {test,is_tagged_tuple,{f,113},[{x,0},2,{atom,arity}]}.
 +    {get_tuple_element,{x,0},1,{x,1}}.
 +    {get_tuple_element,{y,1},0,{y,0}}.
 +    {get_tuple_element,{y,1},1,{y,1}}.
 +    {select_val,{x,1},
 +                {f,113},
 +                {list,[{integer,2},{f,109},{integer,3},{f,108}]}}.
 +  {label,108}.
     {test_heap,2,0}.
 -    {put_list,{y,2},nil,{x,2}}.
 -    {move,{y,3},{x,1}}.
 -    {kill,{y,2}}.
 -    {move,{y,0},{x,0}}.
 +    {put_list,{y,1},nil,{x,2}}.
 +    {move,{y,0},{x,1}}.
 +    {kill,{y,1}}.
 +    {move,{y,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",407}]}.
 -    {call,3,{f,139}}.
 -    {test,is_nonempty_list,{f,135},[{x,0}]}.
 -    {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_nil,{f,135},[{x,2}]}.
 -    {move,{x,1},{y,2}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{y,0},{x,0}}.
 +    {call,3,{f,115}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_cons,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
 +    {get_list,{x,0},{y,1},{x,1}}.
 +    {test,is_nil,{f,111},[{x,1}]}.
 +    {move,{y,2},{x,1}}.
 +    {move,{y,3},{x,0}}.
 +    {move,{y,0},{y,3}}.
 +    {move,{y,1},{y,2}}.
     {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",408}]}.
 -    {call,2,{f,131}}.
 +    {call,2,{f,107}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_list,
 +         {t_tuple,2,true,
 +          #{2 => {t_tuple,3,true,#{3 => {t_list,{t_tuple,0,false,#{}},nil}}}}},
 +         nil}}]}}.
     {test_heap,5,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 +    {put_tuple2,{x,1},{list,[{y,1},{y,0}]}}.
     {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,2}.
     return.
 -  {label,133}.
 -    {move,{y,0},{x,0}}.
 -    {make_fun2,{f,261},0,0,1}.
 +  {label,109}.
 +    {move,{y,3},{x,0}}.
 +    {make_fun2,{f,232},0,0,1}.
     {test_heap,2,1}.
 -    {put_list,{y,2},nil,{x,2}}.
 -    {move,{y,3},{x,1}}.
 -    {kill,{y,2}}.
 +    {put_list,{y,1},nil,{x,2}}.
 +    {move,{y,0},{x,1}}.
 +    {kill,{y,1}}.
     {line,[{location,"couch_key_tree.erl",404}]}.
 -    {call,3,{f,139}}.
 -    {test,is_nonempty_list,{f,136},[{x,0}]}.
 -    {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_nil,{f,136},[{x,2}]}.
 -    {move,{x,1},{y,2}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{y,0},{x,0}}.
 +    {call,3,{f,115}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_cons,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
 +    {get_list,{x,0},{y,1},{x,1}}.
 +    {test,is_nil,{f,112},[{x,1}]}.
 +    {move,{y,2},{x,1}}.
 +    {move,{y,3},{x,0}}.
 +    {move,{y,0},{y,3}}.
 +    {move,{y,1},{y,2}}.
     {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",405}]}.
 -    {call,2,{f,131}}.
 +    {call,2,{f,107}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_list,
 +         {t_tuple,2,true,
 +          #{2 => {t_tuple,3,true,#{3 => {t_list,{t_tuple,0,false,#{}},nil}}}}},
 +         nil}}]}}.
     {test_heap,5,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 +    {put_tuple2,{x,1},{list,[{y,1},{y,0}]}}.
     {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,2}.
     return.
 -  {label,134}.
 -    {test,is_nil,{f,130},[{x,1}]}.
 +  {label,110}.
 +    {test,is_nil,{f,106},[{x,1}]}.
     {move,nil,{x,0}}.
     return.
 -  {label,135}.
 +  {label,111}.
     {line,[{location,"couch_key_tree.erl",407}]}.
     {badmatch,{x,0}}.
 -  {label,136}.
 +  {label,112}.
     {line,[{location,"couch_key_tree.erl",404}]}.
     {badmatch,{x,0}}.
 -  {label,137}.
 +  {label,113}.
     {line,[{location,"couch_key_tree.erl",402}]}.
     {case_end,{x,0}}.


 -{function, map_simple, 3, 139}.
 -  {label,138}.
 +{function, map_simple, 3, 115}.
 +  {label,114}.
     {line,[{location,"couch_key_tree.erl",411}]}.
     {func_info,{atom,couch_key_tree},{atom,map_simple},3}.
 -  {label,139}.
 -    {test,is_nonempty_list,{f,142},[{x,2}]}.
 +  {label,115}.
 +    {test,is_nonempty_list,{f,118},[{x,2}]}.
     {get_list,{x,2},{x,3},{x,4}}.
 -    {test,is_tuple,{f,138},[{x,3}]}.
 -    {test,test_arity,{f,138},[{x,3},3]}.
 -    {allocate,6,5}.
 -    {get_tuple_element,{x,3},0,{y,5}}.
 -    {get_tuple_element,{x,3},1,{y,0}}.
 -    {get_tuple_element,{x,3},2,{x,7}}.
 -    {move,{x,7},{y,1}}.
 -    {move,{x,1},{y,2}}.
 -    {move,{x,0},{y,3}}.
 -    {move,{x,4},{y,4}}.
 -    {test,is_nil,{f,140},[{x,7}]}.
 +    {test,is_tuple,{f,114},[{x,3}]}.
 +    {test,test_arity,{f,114},[{x,3},3]}.
 +    {allocate,5,5}.
 +    {init,{y,0}}.
 +    {move,{x,4},{y,2}}.
 +    {move,{x,1},{y,3}}.
 +    {move,{x,0},{y,4}}.
 +    {get_tuple_element,{x,3},2,{y,1}}.
 +    {test,is_nil,{f,116},[{y,1}]}.
     {move,{atom,leaf},{x,0}}.
 -    {jump,{f,141}}.
 -  {label,140}.
 +    {jump,{f,117}}.
 +  {label,116}.
     {move,{atom,branch},{x,0}}.
 -  {label,141}.
 -    {test_heap,3,1}.
 -    {put_tuple,2,{x,4}}.
 -    {put,{y,2}}.
 -    {put,{y,5}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,0},{x,1}}.
 -    {move,{y,3},{x,3}}.
 -    {trim,1,5}.
 -    {move,{x,4},{x,0}}.
 +  {label,117}.
 +    {test_heap,3,4}.
 +    {get_tuple_element,{x,3},0,{y,0}}.
 +    {put_tuple2,{x,1},{list,[{y,3},{y,0}]}}.
 +    {get_tuple_element,{x,3},1,{x,2}}.
 +    {move,{y,4},{x,3}}.
 +    {swap,{x,2},{x,1}}.
 +    {swap,{x,0},{x,2}}.
     {line,[{location,"couch_key_tree.erl",414}]}.
     {call_fun,3}.
     {line,[{location,"couch_key_tree.erl",422}]}.
 -    {gc_bif,'+',{f,0},1,[{y,1},{integer,1}],{x,1}}.
 -    {move,{x,0},{x,3}}.
 -    {move,{y,0},{x,2}}.
 -    {move,{x,3},{y,0}}.
 -    {move,{y,2},{x,0}}.
 +    {gc_bif,'+',{f,0},1,[{y,3},{integer,1}],{x,1}}.
 +    {move,{y,1},{x,3}}.
 +    {move,{x,0},{y,1}}.
 +    {move,{y,4},{x,0}}.
 +    {move,{x,3},{x,2}}.
     {line,[{location,"couch_key_tree.erl",422}]}.
 -    {call,3,{f,139}}.
 -    {move,{x,0},{x,3}}.
 -    {move,{y,1},{x,1}}.
 +    {call,3,{f,115}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
 +    {move,{y,2},{x,3}}.
     {move,{y,3},{x,2}}.
 -    {move,{x,3},{y,3}}.
 -    {move,{y,2},{x,0}}.
 -    {kill,{y,1}}.
 -    {kill,{y,2}}.
 +    {swap,{y,4},{x,0}}.
 +    {move,{x,2},{x,1}}.
 +    {move,{x,3},{x,2}}.
 +    {move,{y,0},{y,3}}.
 +    {move,{y,1},{y,2}}.
 +    {trim,2,3}.
     {line,[{location,"couch_key_tree.erl",422}]}.
 -    {call,3,{f,139}}.
 +    {call,3,{f,115}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
     {test_heap,6,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{y,4}}.
 -    {put,{y,0}}.
 -    {put,{y,3}}.
 +    {put_tuple2,{x,1},{list,[{y,1},{y,0},{y,2}]}}.
     {put_list,{x,1},{x,0},{x,0}}.
 -    {deallocate,5}.
 +    {deallocate,3}.
     return.
 -  {label,142}.
 -    {test,is_nil,{f,138},[{x,2}]}.
 +  {label,118}.
 +    {test,is_nil,{f,114},[{x,2}]}.
     {move,nil,{x,0}}.
     return.


 -{function, mapfold, 3, 144}.
 -  {label,143}.
 +{function, mapfold, 3, 120}.
 +  {label,119}.
     {line,[{location,"couch_key_tree.erl",424}]}.
     {func_info,{atom,couch_key_tree},{atom,mapfold},3}.
 -  {label,144}.
 -    {test,is_nonempty_list,{f,145},[{x,2}]}.
 +  {label,120}.
 +    {test,is_nonempty_list,{f,121},[{x,2}]}.
     {get_list,{x,2},{x,3},{x,4}}.
 -    {test,is_tuple,{f,143},[{x,3}]}.
 -    {test,test_arity,{f,143},[{x,3},2]}.
 -    {allocate_heap,3,2,5}.
 -    {get_tuple_element,{x,3},0,{y,0}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {move,{x,0},{y,2}}.
 -    {move,{x,4},{y,1}}.
 -    {put_list,{x,6},nil,{x,3}}.
 -    {move,{y,0},{x,2}}.
 +    {test,is_tuple,{f,119},[{x,3}]}.
 +    {test,test_arity,{f,119},[{x,3},2]}.
 +    {allocate_heap,4,2,5}.
 +    {init,{y,0}}.
 +    {move,{x,4},{y,2}}.
 +    {move,{x,0},{y,3}}.
 +    {get_tuple_element,{x,3},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {get_tuple_element,{x,3},0,{y,1}}.
 +    {move,{y,1},{x,2}}.
 +    {move,{x,0},{x,3}}.
 +    {move,{y,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",427}]}.
 -    {call,4,{f,149}}.
 -    {test,is_tuple,{f,147},[{x,0}]}.
 -    {test,test_arity,{f,147},[{x,0},2]}.
 +    {call,4,{f,124}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_cons,
 +                               {t_tuple,3,true,
 +                                   #{3 => {t_list,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {test,is_nonempty_list,{f,147},[{x,1}]}.
 -    {get_list,{x,1},{x,3},{x,4}}.
 -    {test,is_nil,{f,147},[{x,4}]}.
 -    {move,{x,2},{x,1}}.
 -    {move,{y,1},{x,2}}.
 -    {move,{y,2},{x,0}}.
 -    {move,{x,3},{y,2}}.
 -    {kill,{y,1}}.
 +    {get_list,{x,1},{y,0},{x,1}}.
 +    {test,is_nil,{f,122},[{x,1}]}.
 +    {get_tuple_element,{x,0},1,{x,1}}.
 +    {move,{y,2},{x,2}}.
 +    {move,{y,3},{x,0}}.
 +    {move,{y,0},{y,3}}.
 +    {move,{y,1},{y,2}}.
 +    {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",428}]}.
 -    {call,3,{f,144}}.
 -    {test,is_tuple,{f,146},[{x,0}]}.
 -    {test,test_arity,{f,146},[{x,0},2]}.
 +    {call,3,{f,120}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{1 =>
 +            {t_list,
 +             {t_tuple,2,true,
 +              #{2 => {t_tuple,3,true,#{3 => {t_list,any,any}}}}},
 +             nil}}}}]}}.
     {test_heap,8,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {put_tuple,2,{x,3}}.
 -    {put,{y,0}}.
 -    {put,{y,2}}.
 -    {put_list,{x,3},{x,1},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 -    {deallocate,3}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_tuple2,{x,2},{list,[{y,0},{y,1}]}}.
 +    {put_list,{x,2},{x,1},{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
 +    {deallocate,2}.
     return.
 -  {label,145}.
 -    {test,is_nil,{f,143},[{x,2}]}.
 +  {label,121}.
 +    {test,is_nil,{f,119},[{x,2}]}.
     {test_heap,3,2}.
 -    {put_tuple,2,{x,0}}.
 -    {put,nil}.
 -    {put,{x,1}}.
 +    {put_tuple2,{x,0},{list,[nil,{x,1}]}}.
     return.
 -  {label,146}.
 -    {line,[{location,"couch_key_tree.erl",428}]}.
 -    {badmatch,{x,0}}.
 -  {label,147}.
 +  {label,122}.
     {line,[{location,"couch_key_tree.erl",427}]}.
     {badmatch,{x,0}}.


 -{function, mapfold_simple, 4, 149}.
 -  {label,148}.
 +{function, mapfold_simple, 4, 124}.
 +  {label,123}.
     {line,[{location,"couch_key_tree.erl",431}]}.
     {func_info,{atom,couch_key_tree},{atom,mapfold_simple},4}.
 -  {label,149}.
 -    {test,is_nonempty_list,{f,152},[{x,3}]}.
 +  {label,124}.
 +    {test,is_nonempty_list,{f,127},[{x,3}]}.
     {get_list,{x,3},{x,4},{x,5}}.
 -    {test,is_tuple,{f,148},[{x,4}]}.
 -    {test,test_arity,{f,148},[{x,4},3]}.
 -    {allocate,7,6}.
 -    {get_tuple_element,{x,4},0,{y,6}}.
 -    {get_tuple_element,{x,4},1,{y,1}}.
 -    {get_tuple_element,{x,4},2,{x,8}}.
 -    {move,{x,1},{y,0}}.
 -    {move,{x,2},{y,2}}.
 -    {move,{x,0},{y,3}}.
 -    {move,{x,5},{y,4}}.
 -    {move,{x,8},{y,5}}.
 -    {test,is_nil,{f,150},[{x,8}]}.
 -    {move,{atom,leaf},{x,0}}.
 -    {jump,{f,151}}.
 -  {label,150}.
 -    {move,{atom,branch},{x,0}}.
 -  {label,151}.
 -    {test_heap,3,1}.
 -    {put_tuple,2,{x,5}}.
 -    {put,{y,2}}.
 -    {put,{y,6}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,0},{x,3}}.
 -    {move,{y,1},{x,1}}.
 -    {move,{y,3},{x,4}}.
 -    {trim,2,5}.
 -    {move,{x,5},{x,0}}.
 +    {test,is_tuple,{f,123},[{x,4}]}.
 +    {test,test_arity,{f,123},[{x,4},3]}.
 +    {allocate,6,6}.
 +    {init,{y,0}}.
 +    {init,{y,1}}.
 +    {move,{x,5},{y,3}}.
 +    {move,{x,2},{y,4}}.
 +    {move,{x,0},{y,5}}.
 +    {get_tuple_element,{x,4},2,{y,2}}.
 +    {test,is_nil,{f,125},[{y,2}]}.
 +    {move,{atom,leaf},{x,2}}.
 +    {jump,{f,126}}.
 +  {label,125}.
 +    {move,{atom,branch},{x,2}}.
 +  {label,126}.
 +    {test_heap,3,5}.
 +    {get_tuple_element,{x,4},0,{y,1}}.
 +    {put_tuple2,{x,0},{list,[{y,4},{y,1}]}}.
 +    {get_tuple_element,{x,4},1,{x,3}}.
 +    {move,{y,5},{x,4}}.
 +    {swap,{x,1},{x,3}}.
     {line,[{location,"couch_key_tree.erl",434}]}.
     {call_fun,4}.
 -    {test,is_tuple,{f,155},[{x,0}]}.
 -    {test,test_arity,{f,155},[{x,0},2]}.
 -    {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {line,[{location,"couch_key_tree.erl",443}]}.
 -    {gc_bif,'+',{f,0},3,[{y,0},{integer,1}],{x,0}}.
 -    {move,{x,1},{x,4}}.
 -    {move,{x,2},{x,1}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,3},{x,3}}.
 -    {move,{x,4},{y,3}}.
 -    {move,{y,1},{x,0}}.
 +    {test,is_tuple,{f,128},[{x,0}]}.
 +    {test,test_arity,{f,128},[{x,0},2]}.
 +    {get_tuple_element,{x,0},0,{y,0}}.
     {line,[{location,"couch_key_tree.erl",443}]}.
 -    {call,4,{f,149}}.
 -    {test,is_tuple,{f,154},[{x,0}]}.
 -    {test,test_arity,{f,154},[{x,0},2]}.
 +    {gc_bif,'+',{f,0},1,[{y,4},{integer,1}],{x,2}}.
     {get_tuple_element,{x,0},1,{x,1}}.
 -    {move,{y,0},{x,2}}.
     {move,{y,2},{x,3}}.
 +    {kill,{y,2}}.
 +    {move,{y,5},{x,0}}.
 +    {line,[{location,"couch_key_tree.erl",443}]}.
 +    {call,4,{f,124}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_list,
 +                               {t_tuple,3,true,
 +                                   #{3 => {t_list,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {get_tuple_element,{x,0},0,{y,2}}.
 -    {move,{y,1},{x,0}}.
 -    {trim,2,3}.
 +    {get_tuple_element,{x,0},1,{x,1}}.
 +    {move,{y,3},{x,3}}.
 +    {move,{y,4},{x,2}}.
 +    {move,{y,5},{x,0}}.
 +    {move,{y,0},{y,5}}.
 +    {move,{y,1},{y,4}}.
 +    {move,{y,2},{y,3}}.
 +    {trim,3,3}.
     {line,[{location,"couch_key_tree.erl",444}]}.
 -    {call,4,{f,149}}.
 -    {test,is_tuple,{f,153},[{x,0}]}.
 -    {test,test_arity,{f,153},[{x,0},2]}.
 +    {call,4,{f,124}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 =>
 +                           {t_list,
 +                               {t_tuple,3,true,
 +                                   #{3 => {t_list,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {test_heap,9,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {put_tuple,3,{x,3}}.
 -    {put,{y,2}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 -    {put_list,{x,3},{x,1},{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_tuple2,{x,2},{list,[{y,1},{y,2},{y,0}]}}.
 +    {put_list,{x,2},{x,1},{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,3}.
     return.
 -  {label,152}.
 -    {test,is_nil,{f,148},[{x,3}]}.
 +  {label,127}.
 +    {test,is_nil,{f,123},[{x,3}]}.
     {test_heap,3,2}.
 -    {put_tuple,2,{x,0}}.
 -    {put,nil}.
 -    {put,{x,1}}.
 +    {put_tuple2,{x,0},{list,[nil,{x,1}]}}.
     return.
 -  {label,153}.
 -    {line,[{location,"couch_key_tree.erl",444}]}.
 -    {badmatch,{x,0}}.
 -  {label,154}.
 -    {line,[{location,"couch_key_tree.erl",443}]}.
 -    {badmatch,{x,0}}.
 -  {label,155}.
 +  {label,128}.
     {line,[{location,"couch_key_tree.erl",434}]}.
     {badmatch,{x,0}}.


 -{function, map_leafs, 2, 157}.
 -  {label,156}.
 +{function, map_leafs, 2, 130}.
 +  {label,129}.
     {line,[{location,"couch_key_tree.erl",447}]}.
     {func_info,{atom,couch_key_tree},{atom,map_leafs},2}.
 -  {label,157}.
 -    {test,is_nonempty_list,{f,158},[{x,1}]}.
 +  {label,130}.
 +    {test,is_nonempty_list,{f,131},[{x,1}]}.
     {get_list,{x,1},{x,2},{x,3}}.
 -    {test,is_tuple,{f,156},[{x,2}]}.
 -    {test,test_arity,{f,156},[{x,2},2]}.
 -    {allocate_heap,3,2,4}.
 -    {get_tuple_element,{x,2},0,{y,0}}.
 -    {get_tuple_element,{x,2},1,{x,5}}.
 -    {move,{x,0},{y,2}}.
 -    {move,{x,3},{y,1}}.
 -    {put_list,{x,5},nil,{x,2}}.
 -    {move,{y,0},{x,1}}.
 -    {line,[{location,"couch_key_tree.erl",450}]}.
 -    {call,3,{f,161}}.
 -    {test,is_nonempty_list,{f,159},[{x,0}]}.
 -    {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_nil,{f,159},[{x,2}]}.
 -    {move,{x,1},{x,2}}.
 +    {test,is_tuple,{f,129},[{x,2}]}.
 +    {test,test_arity,{f,129},[{x,2},2]}.
 +    {allocate_heap,4,2,4}.
 +    {init,{y,0}}.
 +    {move,{x,3},{y,2}}.
 +    {move,{x,0},{y,3}}.
 +    {get_tuple_element,{x,2},1,{x,0}}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {get_tuple_element,{x,2},0,{y,1}}.
     {move,{y,1},{x,1}}.
 -    {move,{y,2},{x,0}}.
 -    {move,{x,2},{y,2}}.
 -    {kill,{y,1}}.
 +    {move,{x,0},{x,2}}.
 +    {move,{y,3},{x,0}}.
 +    {line,[{location,"couch_key_tree.erl",450}]}.
 +    {call,3,{f,134}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_cons,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
 +    {get_list,{x,0},{y,0},{x,1}}.
 +    {test,is_nil,{f,132},[{x,1}]}.
 +    {move,{y,2},{x,1}}.
 +    {move,{y,3},{x,0}}.
 +    {move,{y,0},{y,3}}.
 +    {move,{y,1},{y,2}}.
 +    {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",451}]}.
 -    {call,2,{f,157}}.
 +    {call,2,{f,130}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_list,
 +         {t_tuple,2,true,
 +          #{2 => {t_tuple,3,true,#{3 => {t_list,{t_tuple,0,false,#{}},nil}}}}},
 +         nil}}]}}.
     {test_heap,5,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,0}}.
 -    {put,{y,2}}.
 +    {put_tuple2,{x,1},{list,[{y,0},{y,1}]}}.
     {put_list,{x,1},{x,0},{x,0}}.
 -    {deallocate,3}.
 +    {deallocate,2}.
     return.
 -  {label,158}.
 -    {test,is_nil,{f,156},[{x,1}]}.
 +  {label,131}.
 +    {test,is_nil,{f,129},[{x,1}]}.
     {move,nil,{x,0}}.
     return.
 -  {label,159}.
 +  {label,132}.
     {line,[{location,"couch_key_tree.erl",450}]}.
     {badmatch,{x,0}}.


 -{function, map_leafs_simple, 3, 161}.
 -  {label,160}.
 +{function, map_leafs_simple, 3, 134}.
 +  {label,133}.
     {line,[{location,"couch_key_tree.erl",453}]}.
     {func_info,{atom,couch_key_tree},{atom,map_leafs_simple},3}.
 -  {label,161}.
 -    {test,is_nonempty_list,{f,163},[{x,2}]}.
 +  {label,134}.
 +    {test,is_nonempty_list,{f,136},[{x,2}]}.
     {get_list,{x,2},{x,3},{x,4}}.
 -    {test,is_tuple,{f,160},[{x,3}]}.
 -    {test,test_arity,{f,160},[{x,3},3]}.
 -    {get_tuple_element,{x,3},0,{x,5}}.
 -    {get_tuple_element,{x,3},1,{x,6}}.
 -    {get_tuple_element,{x,3},2,{x,7}}.
 -    {test,is_nil,{f,162},[{x,7}]}.
 -    {allocate_heap,4,3,7}.
 -    {move,{x,1},{y,3}}.
 -    {move,{x,0},{y,2}}.
 +    {test,is_tuple,{f,133},[{x,3}]}.
 +    {test,test_arity,{f,133},[{x,3},3]}.
 +    {get_tuple_element,{x,3},0,{x,2}}.
 +    {get_tuple_element,{x,3},1,{x,5}}.
 +    {get_tuple_element,{x,3},2,{x,3}}.
 +    {test,is_nil,{f,135},[{x,3}]}.
 +    {allocate_heap,4,3,6}.
 +    {move,{x,2},{y,0}}.
     {move,{x,4},{y,1}}.
 -    {move,{x,5},{y,0}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{y,3}}.
 -    {put,{x,5}}.
 -    {move,{y,2},{x,2}}.
 -    {move,{x,6},{x,1}}.
 +    {move,{x,1},{y,2}}.
 +    {move,{x,0},{y,3}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,2}]}}.
 +    {move,{y,3},{x,2}}.
 +    {move,{x,5},{x,1}}.
     {line,[{location,"couch_key_tree.erl",456}]}.
     {call_fun,2}.
 -    {move,{x,0},{x,3}}.
 -    {move,{y,3},{x,1}}.
 -    {move,{y,1},{x,2}}.
 -    {move,{x,3},{y,3}}.
 -    {move,{y,2},{x,0}}.
 -    {kill,{y,1}}.
 -    {kill,{y,2}}.
 +    {move,{y,1},{x,3}}.
 +    {move,{y,2},{x,2}}.
 +    {swap,{y,3},{x,0}}.
 +    {move,{x,2},{x,1}}.
 +    {move,{x,3},{x,2}}.
 +    {move,{y,0},{y,2}}.
 +    {trim,2,2}.
     {line,[{location,"couch_key_tree.erl",457}]}.
 -    {call,3,{f,161}}.
 +    {call,3,{f,134}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
     {test_heap,6,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{y,0}}.
 -    {put,{y,3}}.
 -    {put,nil}.
 +    {put_tuple2,{x,1},{list,[{y,0},{y,1},nil]}}.
     {put_list,{x,1},{x,0},{x,0}}.
 -    {deallocate,4}.
 +    {deallocate,2}.
     return.
 -  {label,162}.
 -    {allocate_zero,5,8}.
 +  {label,135}.
     {line,[{location,"couch_key_tree.erl",459}]}.
 -    {gc_bif,'+',{f,0},8,[{x,1},{integer,1}],{x,2}}.
 -    {move,{x,1},{y,0}}.
 -    {move,{x,2},{x,1}}.
 -    {move,{x,7},{x,2}}.
 -    {move,{x,0},{y,1}}.
 +    {gc_bif,'+',{f,0},6,[{x,1},{integer,1}],{x,6}}.
 +    {allocate,5,7}.
 +    {move,{x,2},{y,0}}.
 +    {move,{x,5},{y,1}}.
     {move,{x,4},{y,2}}.
 -    {move,{x,6},{y,3}}.
 -    {move,{x,5},{y,4}}.
 +    {move,{x,1},{y,3}}.
 +    {move,{x,0},{y,4}}.
 +    {move,{x,3},{x,2}}.
 +    {move,{x,6},{x,1}}.
     {line,[{location,"couch_key_tree.erl",459}]}.
 -    {call,3,{f,161}}.
 -    {move,{x,0},{x,3}}.
 -    {move,{y,0},{x,1}}.
 -    {move,{y,2},{x,2}}.
 -    {move,{x,3},{y,2}}.
 -    {move,{y,1},{x,0}}.
 +    {call,3,{f,134}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
 +    {move,{y,2},{x,3}}.
 +    {move,{y,3},{x,2}}.
 +    {swap,{y,4},{x,0}}.
 +    {move,{x,2},{x,1}}.
 +    {move,{x,3},{x,2}}.
 +    {move,{y,0},{y,3}}.
 +    {move,{y,1},{y,2}}.
     {trim,2,3}.
     {line,[{location,"couch_key_tree.erl",459}]}.
 -    {call,3,{f,161}}.
 +    {call,3,{f,134}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,3,true,
 +                         #{3 =>
 +                               {t_list,
 +                                   {t_tuple,3,true,#{3 => {t_list,any,any}}},
 +                                   nil}}},
 +                     nil}}]}}.
     {test_heap,6,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{y,2}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 +    {put_tuple2,{x,1},{list,[{y,1},{y,0},{y,2}]}}.
     {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,3}.
     return.
 -  {label,163}.
 -    {test,is_nil,{f,160},[{x,2}]}.
 +  {label,136}.
 +    {test,is_nil,{f,133},[{x,2}]}.
     {move,nil,{x,0}}.
     return.


 -{function, stem, 2, 165}.
 -  {label,164}.
 +{function, stem, 2, 138}.
 +  {label,137}.
     {line,[{location,"couch_key_tree.erl",461}]}.
     {func_info,{atom,couch_key_tree},{atom,stem},2}.
 -  {label,165}.
 +  {label,138}.
     {allocate,4,2}.
     {init,{y,0}}.
 -    {move,{x,0},{y,2}}.
     {move,{x,1},{y,1}}.
 +    {move,{x,0},{y,2}}.
 +    {'try',{y,3},{f,139}}.
     {move,{x,1},{x,0}}.
 -    {'try',{y,3},{f,166}}.
 -    {make_fun2,{f,257},0,0,1}.
 +    {make_fun2,{f,229},0,0,1}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_tuple,2,true,#{}}}]}}.
     {move,{x,0},{y,0}}.
     {line,[{location,"couch_key_tree.erl",468}]}.
     {call_ext,0,{extfunc,sets,new,0}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,nil}.
 +    {put_tuple2,{x,1},{list,[{x,0},nil]}}.
     {move,{y,2},{x,2}}.
     {move,{y,0},{x,0}}.
     {kill,{y,0}}.
     {line,[{location,"couch_key_tree.erl",463}]}.
     {call_ext,3,{extfunc,lists,foldl,3}}.
 -    {test,is_tuple,{f,168},[{x,0}]}.
 -    {test,test_arity,{f,168},[{x,0},2]}.
 +    {test,is_tuple,{f,141},[{x,0}]}.
 +    {test,test_arity,{f,141},[{x,0},2]}.
     {get_tuple_element,{x,0},1,{x,0}}.
     {line,[{location,"couch_key_tree.erl",471}]}.
     {call_ext,1,{extfunc,lists,sort,1}}.
     {try_end,{y,3}}.
     {deallocate,4}.
     return.
 -  {label,166}.
 +  {label,139}.
     {try_case,{y,3}}.
 -    {test,is_eq_exact,{f,167},[{x,0},{atom,throw}]}.
 -    {test,is_eq_exact,{f,167},[{x,1},{atom,dupe_keys}]}.
 +    {test,is_eq_exact,{f,140},[{x,0},{atom,throw}]}.
 +    {test,is_eq_exact,{f,140},[{x,1},{atom,dupe_keys}]}.
     {move,{y,1},{x,1}}.
     {move,{y,2},{x,0}}.
 -    {call_last,2,{f,187},4}.
 -  {label,167}.
 -    {line,[]}.
 +    {call_last,2,{f,160},4}.
 +  {label,140}.
     {bif,raise,{f,0},[{x,2},{x,1}],{x,0}}.
 -  {label,168}.
 -    {line,[{location,"couch_key_tree.erl",463}]}.
 +  {label,141}.
 +    {line,[{scope,[2]},{location,"couch_key_tree.erl",463}]}.
     {badmatch,{x,0}}.


 -{function, stem_tree, 3, 170}.
 -  {label,169}.
 +{function, stem_tree, 3, 143}.
 +  {label,142}.
     {line,[{location,"couch_key_tree.erl",477}]}.
     {func_info,{atom,couch_key_tree},{atom,stem_tree},3}.
 -  {label,170}.
 -    {test,is_tuple,{f,169},[{x,0}]}.
 -    {test,test_arity,{f,169},[{x,0},2]}.
 +  {label,143}.
 +    {test,is_tuple,{f,142},[{x,0}]}.
 +    {test,test_arity,{f,142},[{x,0},2]}.
     {allocate,1,3}.
 -    {get_tuple_element,{x,0},1,{x,4}}.
 -    {get_tuple_element,{x,0},0,{x,0}}.
 +    {get_tuple_element,{x,0},0,{y,0}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
     {move,{x,2},{x,3}}.
     {move,{x,1},{x,2}}.
 -    {move,{x,4},{x,1}}.
 -    {move,{x,0},{y,0}}.
 +    {move,{x,0},{x,1}}.
 +    {move,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",478}]}.
 -    {call,4,{f,175}}.
 -    {test,is_tuple,{f,173},[{x,0}]}.
 -    {select_tuple_arity,{x,0},{f,173},{list,[4,{f,171},3,{f,172}]}}.
 -  {label,171}.
 +    {call,4,{f,148}}.
 +    {'%',{var_info,{x,0},[{type,{t_tuple,3,false,#{2 => number}}}]}}.
 +    {select_tuple_arity,{x,0},{f,146},{list,[3,{f,145},4,{f,144}]}}.
 +  {label,144}.
     {test_heap,8,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
     {get_tuple_element,{x,0},2,{x,2}}.
 -    {get_tuple_element,{x,0},3,{x,3}}.
 -    {put_tuple,2,{x,4}}.
 -    {put,{y,0}}.
 -    {put,{x,2}}.
 -    {put_list,{x,4},{x,3},{x,2}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 +    {get_tuple_element,{x,0},3,{x,0}}.
 +    {put_tuple2,{x,2},{list,[{y,0},{x,2}]}}.
 +    {put_list,{x,2},{x,0},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,1}.
     return.
 -  {label,172}.
 +  {label,145}.
     {test_heap,3,1}.
     {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},2,{x,2}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{x,2}}.
 +    {get_tuple_element,{x,0},2,{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,1}.
     return.
 -  {label,173}.
 +  {label,146}.
     {line,[{location,"couch_key_tree.erl",478}]}.
     {case_end,{x,0}}.


 -{function, stem_tree, 4, 175}.
 -  {label,174}.
 +{function, stem_tree, 4, 148}.
 +  {label,147}.
     {line,[{location,"couch_key_tree.erl",485}]}.
     {func_info,{atom,couch_key_tree},{atom,stem_tree},4}.
 -  {label,175}.
 -    {test,is_tuple,{f,174},[{x,1}]}.
 -    {test,test_arity,{f,174},[{x,1},3]}.
 +  {label,148}.
 +    {test,is_tuple,{f,147},[{x,1}]}.
 +    {test,test_arity,{f,147},[{x,1},3]}.
     {get_tuple_element,{x,1},0,{x,4}}.
 -    {get_tuple_element,{x,1},1,{x,5}}.
 -    {get_tuple_element,{x,1},2,{x,6}}.
 -    {test,is_nil,{f,176},[{x,6}]}.
 +    {get_tuple_element,{x,1},2,{x,5}}.
 +    {test,is_nil,{f,149},[{x,5}]}.
     {allocate,2,5}.
 +    {move,{x,2},{y,0}}.
     {move,{x,1},{y,1}}.
     {move,{x,3},{x,1}}.
 -    {move,{x,2},{y,0}}.
     {move,{x,4},{x,0}}.
     {line,[{location,"couch_key_tree.erl",486}]}.
 -    {call,2,{f,182}}.
 +    {call,2,{f,155}}.
     {line,[{location,"couch_key_tree.erl",486}]}.
     {gc_bif,'-',{f,0},1,[{y,0},{integer,1}],{x,1}}.
     {test_heap,5,2}.
 -    {put_tuple,4,{x,2}}.
 -    {put,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{y,1}}.
 -    {put,nil}.
 -    {move,{x,2},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{x,1},{y,1},nil]}}.
     {deallocate,2}.
     return.
 -  {label,176}.
 -    {allocate,5,7}.
 -    {move,{x,0},{y,2}}.
 -    {move,{x,3},{x,1}}.
 -    {move,{x,2},{y,0}}.
 -    {move,{x,6},{y,1}}.
 +  {label,149}.
 +    {allocate,7,6}.
 +    {init,{y,0}}.
 +    {init,{y,1}}.
 +    {move,{x,4},{y,2}}.
     {move,{x,5},{y,3}}.
 -    {move,{x,4},{y,4}}.
 +    {move,{x,2},{y,4}}.
 +    {move,{x,1},{y,5}}.
 +    {move,{x,0},{y,6}}.
 +    {move,{x,3},{x,1}}.
     {move,{x,4},{x,0}}.
     {line,[{location,"couch_key_tree.erl",488}]}.
 -    {call,2,{f,182}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,2},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,2},{y,0}}.
 -    {make_fun2,{f,251},0,0,2}.
 +    {call,2,{f,155}}.
 +    {move,{y,4},{x,2}}.
 +    {move,{x,0},{y,4}}.
 +    {move,{y,6},{x,0}}.
 +    {move,{x,2},{x,1}}.
 +    {make_fun2,{f,223},0,0,2}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_tuple,4,true,#{}}}]}}.
     {test_heap,5,1}.
 -    {put_tuple,4,{x,1}}.
 -    {put,{y,0}}.
 -    {put,{integer,-1}}.
 -    {put,nil}.
 -    {put,nil}.
 -    {move,{y,1},{x,2}}.
 -    {kill,{y,0}}.
 -    {kill,{y,1}}.
 +    {put_tuple2,{x,1},{list,[{y,4},{integer,-1},nil,nil]}}.
 +    {move,{y,3},{x,2}}.
 +    {kill,{y,3}}.
 +    {kill,{y,4}}.
     {line,[{location,"couch_key_tree.erl",489}]}.
     {call_ext,3,{extfunc,lists,foldl,3}}.
 -    {test,is_tuple,{f,180},[{x,0}]}.
 -    {test,test_arity,{f,180},[{x,0},4]}.
 -    {get_tuple_element,{x,0},0,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 -    {get_tuple_element,{x,0},2,{x,3}}.
 -    {get_tuple_element,{x,0},3,{x,4}}.
 -    {gc_bif,length,{f,177},5,[{x,3}],{x,0}}.
 -    {test,is_lt,{f,177},[{integer,0},{x,2}]}.
 -    {test,is_lt,{f,177},[{integer,0},{x,0}]}.
 -    {move,{x,2},{y,0}}.
 -    {move,{x,4},{y,1}}.
 -    {move,{x,1},{y,2}}.
 -    {move,{x,3},{x,0}}.
 +    {test,is_tuple,{f,153},[{x,0}]}.
 +    {test,test_arity,{f,153},[{x,0},4]}.
 +    {get_tuple_element,{x,0},0,{y,4}}.
 +    {get_tuple_element,{x,0},1,{y,3}}.
 +    {get_tuple_element,{x,0},2,{y,1}}.
 +    {get_tuple_element,{x,0},3,{y,0}}.
 +    {test,is_lt,{f,150},[{integer,0},{y,3}]}.
 +    {gc_bif,length,{f,150},0,[{y,1}],{x,0}}.
 +    {test,is_lt,{f,150},[{integer,0},{x,0}]}.
 +    {move,{y,1},{x,0}}.
 +    {move,{y,0},{y,6}}.
 +    {trim,2,5}.
     {line,[{location,"couch_key_tree.erl",510}]}.
     {call_ext,1,{extfunc,lists,reverse,1}}.
     {test_heap,4,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{y,4}}.
 -    {put,{y,3}}.
 -    {put,{x,0}}.
 +    {get_tuple_element,{y,3},1,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{y,0},{x,1},{x,0}]}}.
     {line,[{location,"couch_key_tree.erl",511}]}.
 -    {gc_bif,'-',{f,0},2,[{y,0},{integer,1}],{x,0}}.
 +    {gc_bif,'-',{f,0},1,[{y,1},{integer,1}],{x,1}}.
     {test_heap,5,2}.
 -    {put_tuple,4,{x,2}}.
 -    {put,{y,2}}.
 -    {put,{x,0}}.
 -    {put,{x,1}}.
 -    {put,{y,1}}.
 -    {move,{x,2},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{y,2},{x,1},{x,0},{y,4}]}}.
     {deallocate,5}.
     return.
 -  {label,177}.
 -    {test,is_eq_exact,{f,178},[{x,2},{integer,0}]}.
 -    {gc_bif,length,{f,178},5,[{x,3}],{x,0}}.
 -    {test,is_lt,{f,178},[{integer,0},{x,0}]}.
 -    {move,{y,2},{x,0}}.
 -    {move,{x,3},{y,2}}.
 -    {move,{x,4},{y,3}}.
 -    {move,{x,1},{y,4}}.
 -    {make_fun2,{f,249},0,0,1}.
 -    {move,{x,0},{x,1}}.
 -    {move,{y,2},{x,0}}.
 -    {move,{x,1},{y,2}}.
 +  {label,150}.
 +    {test,is_eq_exact,{f,151},[{y,3},{integer,0}]}.
 +    {gc_bif,length,{f,151},0,[{y,1}],{x,0}}.
 +    {test,is_lt,{f,151},[{integer,0},{x,0}]}.
 +    {move,{y,6},{x,0}}.
 +    {make_fun2,{f,221},0,0,1}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_tuple,2,true,#{1 => number}}}]}}.
 +    {move,{x,0},{y,6}}.
 +    {move,{y,1},{x,0}}.
 +    {move,{y,0},{y,5}}.
 +    {trim,4,3}.
     {line,[{location,"couch_key_tree.erl",517}]}.
     {call_ext,1,{extfunc,lists,reverse,1}}.
     {move,{x,0},{x,1}}.
     {move,{y,2},{x,0}}.
 -    {trim,3,2}.
 +    {move,{y,0},{y,2}}.
 +    {trim,1,2}.
     {line,[{location,"couch_key_tree.erl",513}]}.
     {call_ext,2,{extfunc,lists,map,2}}.
     {move,{y,0},{x,1}}.
 @@ -2180,77 +2388,79 @@
     {line,[{location,"couch_key_tree.erl",519}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,4,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{y,0}}.
 -    {put,{integer,-1}}.
 -    {put,{x,0}}.
 -    {move,{x,1},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{y,0},{integer,-1},{x,0}]}}.
     {deallocate,1}.
     return.
 -  {label,178}.
 -    {gc_bif,length,{f,179},5,[{x,3}],{x,0}}.
 -    {test,is_lt,{f,179},[{x,2},{integer,0}]}.
 -    {test,is_eq_exact,{f,179},[{x,0},{integer,0}]}.
 +  {label,151}.
 +    {test,is_lt,{f,152},[{y,3},{integer,0}]}.
 +    {gc_bif,length,{f,152},0,[{y,1}],{x,0}}.
 +    {test,is_eq_exact,{f,152},[{x,0},{integer,0}]}.
     {line,[{location,"couch_key_tree.erl",521}]}.
 -    {gc_bif,'-',{f,0},5,[{x,2},{integer,1}],{x,0}}.
 -    {test_heap,4,5}.
 -    {put_tuple,3,{x,2}}.
 -    {put,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{x,4}}.
 -    {move,{x,2},{x,0}}.
 -    {deallocate,5}.
 +    {gc_bif,'-',{f,0},0,[{y,3},{integer,1}],{x,0}}.
 +    {test_heap,4,1}.
 +    {put_tuple2,{x,0},{list,[{y,4},{x,0},{y,0}]}}.
 +    {deallocate,7}.
     return.
 -  {label,179}.
 +  {label,152}.
     {line,[{location,"couch_key_tree.erl",508}]}.
 -    {case_end,{x,2}}.
 -  {label,180}.
 +    {case_end,{y,3}}.
 +  {label,153}.
     {line,[{location,"couch_key_tree.erl",507}]}.
     {badmatch,{x,0}}.


 -{function, check_key, 2, 182}.
 -  {label,181}.
 +{function, check_key, 2, 155}.
 +  {label,154}.
     {line,[{location,"couch_key_tree.erl",524}]}.
     {func_info,{atom,couch_key_tree},{atom,check_key},2}.
 -  {label,182}.
 +  {label,155}.
     {allocate,2,2}.
     {move,{x,1},{y,0}}.
     {move,{x,0},{y,1}}.
     {line,[{location,"couch_key_tree.erl",525}]}.
     {call_ext,2,{extfunc,sets,is_element,2}}.
 -    {test,is_atom,{f,185},[{x,0}]}.
     {select_val,{x,0},
 -                {f,185},
 -                {list,[{atom,false},{f,183},{atom,true},{f,184}]}}.
 -  {label,183}.
 +                {f,158},
 +                {list,[{atom,false},{f,157},{atom,true},{f,156}]}}.
 +  {label,156}.
 +    {move,{atom,dupe_keys},{x,0}}.
 +    {line,[{location,"couch_key_tree.erl",527}]}.
 +    {call_ext_last,1,{extfunc,erlang,throw,1},2}.
 +  {label,157}.
     {move,{y,0},{x,1}}.
     {move,{y,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",529}]}.
     {call_ext_last,2,{extfunc,sets,add_element,2},2}.
 -  {label,184}.
 -    {move,{atom,dupe_keys},{x,0}}.
 -    {line,[{location,"couch_key_tree.erl",527}]}.
 -    {call_ext,1,{extfunc,erlang,throw,1}}.
 -  {label,185}.
 +  {label,158}.
     {line,[{location,"couch_key_tree.erl",525}]}.
     {case_end,{x,0}}.


 -{function, repair_tree, 2, 187}.
 -  {label,186}.
 +{function, repair_tree, 2, 160}.
 +  {label,159}.
     {line,[{location,"couch_key_tree.erl",532}]}.
     {func_info,{atom,couch_key_tree},{atom,repair_tree},2}.
 -  {label,187}.
 +  {label,160}.
     {allocate,1,2}.
     {move,{x,0},{y,0}}.
     {move,{x,1},{x,0}}.
 -    {make_fun2,{f,246},0,0,1}.
 -    {move,{x,0},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,1},{y,0}}.
 +    {make_fun2,{f,218},0,0,1}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{fun_type,
 +                 {t_tuple,2,true,#{1 => number,2 => {t_list,any,nil}}}}]}}.
 +    {swap,{y,0},{x,0}}.
     {line,[{location,"couch_key_tree.erl",540}]}.
 -    {call,1,{f,98}}.
 +    {call,1,{f,74}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,2,true,#{}},nil}}},
 +                     nil}}]}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
     {kill,{y,0}}.
 @@ -2259,83 +2469,95 @@
     {line,[{location,"couch_key_tree.erl",534}]}.
     {call_ext,1,{extfunc,lists,sort,1}}.
     {move,{x,0},{y,0}}.
 -    {make_fun2,{f,240},0,0,0}.
 +    {make_fun2,{f,213},0,0,0}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_list,any,nil}}]}}.
     {move,{y,0},{x,2}}.
     {move,nil,{x,1}}.
     {line,[{location,"couch_key_tree.erl",545}]}.
     {call_ext_last,3,{extfunc,lists,foldl,3},1}.


 -{function, value_pref, 2, 189}.
 -  {label,188}.
 +{function, value_pref, 2, 162}.
 +  {label,161}.
     {line,[{location,"couch_key_tree.erl",557}]}.
     {func_info,{atom,couch_key_tree},{atom,value_pref},2}.
 -  {label,189}.
 -    {bif,tuple_size,{f,190},[{x,0}],{x,2}}.
 -    {test,is_ne_exact,{f,194},[{x,2},{integer,3}]}.
 -    {test,test_arity,{f,190},[{x,0},4]}.
 -    {jump,{f,194}}.
 -  {label,190}.
 -    {bif,tuple_size,{f,192},[{x,1}],{x,2}}.
 -    {test,is_ne_exact,{f,191},[{x,2},{integer,3}]}.
 -    {test,test_arity,{f,192},[{x,1},4]}.
 -  {label,191}.
 -    {move,{x,1},{x,0}}.
 +  {label,162}.
 +    {test,is_tuple,{f,164},[{x,0}]}.
 +    {test,test_arity,{f,163},[{x,0},3]}.
     return.
 -  {label,192}.
 -    {test,is_nil,{f,193},[{x,0}]}.
 -    {move,{x,1},{x,0}}.
 +  {label,163}.
 +    {test,test_arity,{f,164},[{x,0},4]}.
     return.
 -  {label,193}.
 -    {test,is_nil,{f,194},[{x,1}]}.
 +  {label,164}.
 +    {test,is_tuple,{f,166},[{x,1}]}.
 +    {test,test_arity,{f,165},[{x,1},3]}.
 +    {jump,{f,167}}.
 +  {label,165}.
 +    {test,test_arity,{f,166},[{x,1},4]}.
 +    {jump,{f,167}}.
 +  {label,166}.
 +    {test,is_nil,{f,168},[{x,0}]}.
 +  {label,167}.
 +    {move,{x,1},{x,0}}.
     return.
 -  {label,194}.
 +  {label,168}.
     return.


 -{function, gen_and_stem, 0, 196}.
 -  {label,195}.
 +{function, gen_and_stem, 0, 170}.
 +  {label,169}.
     {line,[{location,"couch_key_tree.erl",578}]}.
     {func_info,{atom,couch_key_tree},{atom,gen_and_stem},0}.
 -  {label,196}.
 +  {label,170}.
     {move,{float,0.0008},{x,1}}.
     {move,{literal,{1647,841737,351137}},{x,2}}.
     {move,{integer,7000},{x,0}}.
 -    {call_only,3,{f,198}}.
 +    {call_only,3,{f,172}}.


 -{function, gen_and_stem, 3, 198}.
 -  {label,197}.
 +{function, gen_and_stem, 3, 172}.
 +  {label,171}.
     {line,[{location,"couch_key_tree.erl",581}]}.
     {func_info,{atom,couch_key_tree},{atom,gen_and_stem},3}.
 -  {label,198}.
 +  {label,172}.
     {allocate_zero,4,3}.
     {line,[{location,"couch_key_tree.erl",582}]}.
 -    {call,3,{f,203}}.
 -    {test,is_tuple,{f,199},[{x,0}]}.
 -    {test,test_arity,{f,199},[{x,0},2]}.
 -    {get_tuple_element,{x,0},1,{y,3}}.
 +    {call,3,{f,176}}.
 +    {'%',
 +     {var_info,
 +      {x,0},
 +      [{type,
 +        {t_tuple,2,true,
 +         #{2 =>
 +            {t_cons,
 +             {t_tuple,2,true,
 +              #{1 => {t_integer,{1,1}},
 +                2 =>
 +                 {t_tuple,3,true,#{2 => {t_atom,[x]},3 => {t_list,any,any}}}}},
 +             nil}}}}]}}.
 +    {move,{x,0},{y,3}}.
     {line,[{location,"couch_key_tree.erl",583}]}.
     {call_ext,0,{extfunc,erlang,garbage_collect,0}}.
     {bif,self,{f,0},[],{x,0}}.
     {move,{integer,500},{x,1}}.
     {line,[{location,"couch_key_tree.erl",585}]}.
 -    {call,2,{f,226}}.
 +    {call,2,{f,199}}.
     {move,{x,0},{y,2}}.
     {line,[{location,"couch_key_tree.erl",586}]}.
     {call_ext,0,{extfunc,erlang,monotonic_time,0}}.
 -    {move,{x,0},{x,2}}.
 +    {get_tuple_element,{y,3},1,{x,1}}.
 +    {move,{x,0},{y,3}}.
 +    {move,{x,1},{x,0}}.
     {move,{integer,1000},{x,1}}.
 -    {move,{y,3},{x,0}}.
 -    {move,{x,2},{y,3}}.
     {line,[{location,"couch_key_tree.erl",588}]}.
 -    {call,2,{f,165}}.
 +    {call,2,{f,138}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,any,nil}}]}}.
     {line,[{location,"couch_key_tree.erl",590}]}.
     {call_ext,0,{extfunc,erlang,monotonic_time,0}}.
     {move,{x,0},{y,1}}.
     {move,{y,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",591}]}.
 -    {call,1,{f,221}}.
 +    {call,1,{f,194}}.
     {move,{x,0},{y,0}}.
     {line,[{location,"couch_key_tree.erl",593}]}.
     {call_ext,0,{extfunc,erlang,garbage_collect,0}}.
 @@ -2344,77 +2566,80 @@
     {call_ext,1,{extfunc,erlang,unlink,1}}.
     {move,{atom,kill},{x,1}}.
     {move,{y,2},{x,0}}.
 -    {kill,{y,2}}.
 +    {move,{y,0},{y,2}}.
 +    {trim,1,3}.
     {line,[{location,"couch_key_tree.erl",595}]}.
     {call_ext,2,{extfunc,erlang,exit,2}}.
 -    {move,{y,3},{x,1}}.
 -    {move,{y,1},{x,0}}.
 -    {kill,{y,1}}.
 -    {kill,{y,3}}.
 +    {move,{y,2},{x,1}}.
 +    {move,{y,0},{x,0}}.
 +    {move,{y,1},{y,2}}.
 +    {trim,2,1}.
     {line,[{location,"couch_key_tree.erl",597}]}.
 -    {call,2,{f,216}}.
 +    {call,2,{f,189}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{y,0}}.
 -    {move,{x,1},{x,0}}.
 -    {deallocate,4}.
 +    {put_tuple2,{x,0},{list,[{x,0},{y,0}]}}.
 +    {deallocate,1}.
     return.
 -  {label,199}.
 -    {line,[{location,"couch_key_tree.erl",582}]}.
 -    {badmatch,{x,0}}.


 -{function, gen, 0, 201}.
 -  {label,200}.
 +{function, gen, 0, 174}.
 +  {label,173}.
     {line,[{location,"couch_key_tree.erl",600}]}.
     {func_info,{atom,couch_key_tree},{atom,gen},0}.
 -  {label,201}.
 +  {label,174}.
     {move,{float,0.0008},{x,1}}.
     {move,{literal,{1647,841737,351137}},{x,2}}.
     {move,{integer,7000},{x,0}}.
 -    {call_only,3,{f,203}}.
 +    {call_only,3,{f,176}}.


 -{function, gen, 3, 203}.
 -  {label,202}.
 +{function, gen, 3, 176}.
 +  {label,175}.
     {line,[{location,"couch_key_tree.erl",603}]}.
     {func_info,{atom,couch_key_tree},{atom,gen},3}.
 -  {label,203}.
 +  {label,176}.
     {allocate,3,3}.
 -    {move,{x,0},{y,1}}.
 -    {move,{x,1},{y,0}}.
 +    {move,{x,2},{y,0}}.
 +    {move,{x,1},{y,1}}.
 +    {move,{x,0},{y,2}}.
     {move,{x,2},{x,1}}.
 -    {move,{x,1},{y,2}}.
     {move,{atom,exrop},{x,0}}.
     {line,[{location,"couch_key_tree.erl",604}]}.
     {call_ext,2,{extfunc,rand,seed,2}}.
 -    {move,{y,0},{x,1}}.
 -    {move,{y,1},{x,0}}.
 +    {move,{y,1},{x,1}}.
 +    {move,{y,2},{x,0}}.
 +    {move,{y,0},{y,2}}.
     {trim,2,1}.
     {line,[{location,"couch_key_tree.erl",605}]}.
 -    {call,2,{f,210}}.
 +    {call,2,{f,183}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,3,true,
 +                     #{2 => {t_atom,[x]},
 +                       3 =>
 +                           {t_list,
 +                               {t_tuple,3,true,
 +                                   #{2 => {t_atom,[x]},
 +                                     3 => {t_list,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {test_heap,8,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{integer,1}}.
 -    {put,{x,0}}.
 -    {put_list,{x,1},nil,{x,1}}.
 -    {put_tuple,2,{x,0}}.
 -    {put,{y,0}}.
 -    {put,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{integer,1},{x,0}]}}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {put_tuple2,{x,0},{list,[{y,0},{x,0}]}}.
     {deallocate,1}.
     return.


 -{function, save, 2, 205}.
 -  {label,204}.
 +{function, save, 2, 178}.
 +  {label,177}.
     {line,[{location,"couch_key_tree.erl",607}]}.
     {func_info,{atom,couch_key_tree},{atom,save},2}.
 -  {label,205}.
 +  {label,178}.
     {allocate,1,2}.
     {move,{x,0},{y,0}}.
     {move,{x,1},{x,0}}.
 -    {line,[{location,"couch_key_tree.erl",608}]}.
     {call_ext,1,{extfunc,erlang,term_to_binary,1}}.
     {move,{x,0},{x,1}}.
     {move,{y,0},{x,0}}.
 @@ -2422,110 +2647,140 @@
     {call_ext_last,2,{extfunc,file,write_file,2},1}.


 -{function, load, 1, 207}.
 -  {label,206}.
 +{function, load, 1, 180}.
 +  {label,179}.
     {line,[{location,"couch_key_tree.erl",610}]}.
     {func_info,{atom,couch_key_tree},{atom,load},1}.
 -  {label,207}.
 +  {label,180}.
     {allocate,0,1}.
     {line,[{location,"couch_key_tree.erl",611}]}.
     {call_ext,1,{extfunc,file,read_file,1}}.
 -    {test,is_tagged_tuple,{f,208},[{x,0},2,{atom,ok}]}.
 +    {test,is_tagged_tuple,{f,181},[{x,0},2,{atom,ok}]}.
     {get_tuple_element,{x,0},1,{x,0}}.
     {line,[{location,"couch_key_tree.erl",612}]}.
     {call_ext_last,1,{extfunc,erlang,binary_to_term,1},0}.
 -  {label,208}.
 +  {label,181}.
     {line,[{location,"couch_key_tree.erl",611}]}.
     {badmatch,{x,0}}.


 -{function, revnode, 2, 210}.
 -  {label,209}.
 +{function, revnode, 2, 183}.
 +  {label,182}.
     {line,[{location,"couch_key_tree.erl",614}]}.
     {func_info,{atom,couch_key_tree},{atom,revnode},2}.
 -  {label,210}.
 -    {test,is_eq_exact,{f,211},[{x,0},{integer,0}]}.
 +  {label,183}.
 +    {test,is_eq_exact,{f,184},[{x,0},{integer,0}]}.
     {allocate,0,0}.
     {line,[{location,"couch_key_tree.erl",615}]}.
 -    {call,0,{f,214}}.
 +    {call,0,{f,187}}.
     {test_heap,4,1}.
 -    {put_tuple,3,{x,1}}.
 -    {put,{x,0}}.
 -    {put,{atom,x}}.
 -    {put,nil}.
 -    {move,{x,1},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,0},{atom,x},nil]}}.
     {deallocate,0}.
     return.
 -  {label,211}.
 +  {label,184}.
     {allocate,3,2}.
     {init,{y,0}}.
     {move,{x,1},{y,1}}.
     {move,{x,0},{y,2}}.
     {line,[{location,"couch_key_tree.erl",617}]}.
     {call_ext,0,{extfunc,rand,uniform,0}}.
 -    {test,is_lt,{f,212},[{x,0},{y,1}]}.
 +    {test,is_lt,{f,185},[{x,0},{y,1}]}.
     {line,[{location,"couch_key_tree.erl",619}]}.
 -    {call,0,{f,214}}.
 +    {call,0,{f,187}}.
     {line,[{location,"couch_key_tree.erl",620}]}.
     {gc_bif,'-',{f,0},1,[{y,2},{integer,1}],{x,1}}.
     {move,{x,0},{y,0}}.
 +    {move,{y,1},{x,2}}.
     {move,{x,1},{x,0}}.
 -    {move,{y,1},{x,1}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",620}]}.
 -    {call,2,{f,210}}.
 +    {call,2,{f,183}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,3,true,
 +                     #{2 => {t_atom,[x]},
 +                       3 =>
 +                           {t_list,
 +                               {t_tuple,3,true,
 +                                   #{2 => {t_atom,[x]},
 +                                     3 => {t_list,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {line,[{location,"couch_key_tree.erl",621}]}.
     {gc_bif,'-',{f,0},1,[{y,2},{integer,1}],{x,1}}.
     {move,{x,0},{y,2}}.
 +    {move,{y,1},{x,2}}.
     {move,{x,1},{x,0}}.
 -    {move,{y,1},{x,1}}.
 -    {kill,{y,1}}.
 +    {move,{x,2},{x,1}}.
 +    {move,{y,0},{y,1}}.
 +    {trim,1,2}.
     {line,[{location,"couch_key_tree.erl",621}]}.
 -    {call,2,{f,210}}.
 +    {call,2,{f,183}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,3,true,
 +                     #{2 => {t_atom,[x]},
 +                       3 =>
 +                           {t_list,
 +                               {t_tuple,3,true,
 +                                   #{2 => {t_atom,[x]},
 +                                     3 => {t_list,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {test_heap,8,1}.
 -    {put_list,{x,0},nil,{x,1}}.
 -    {put_list,{y,2},{x,1},{x,1}}.
 -    {put_tuple,3,{x,0}}.
 -    {put,{y,0}}.
 -    {put,{atom,x}}.
 -    {put,{x,1}}.
 -    {deallocate,3}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {put_list,{y,1},{x,0},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{y,0},{atom,x},{x,0}]}}.
 +    {deallocate,2}.
     return.
 -  {label,212}.
 +  {label,185}.
     {line,[{location,"couch_key_tree.erl",624}]}.
 -    {call,0,{f,214}}.
 +    {call,0,{f,187}}.
     {line,[{location,"couch_key_tree.erl",624}]}.
     {gc_bif,'-',{f,0},1,[{y,2},{integer,1}],{x,1}}.
     {move,{x,0},{y,2}}.
 +    {move,{y,1},{x,2}}.
     {move,{x,1},{x,0}}.
 -    {move,{y,1},{x,1}}.
 +    {move,{x,2},{x,1}}.
     {trim,2,1}.
     {line,[{location,"couch_key_tree.erl",624}]}.
 -    {call,2,{f,210}}.
 +    {call,2,{f,183}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,3,true,
 +                     #{2 => {t_atom,[x]},
 +                       3 =>
 +                           {t_list,
 +                               {t_tuple,3,true,
 +                                   #{2 => {t_atom,[x]},
 +                                     3 => {t_list,{t_tuple,0,false,#{}},nil}}},
 +                               nil}}}}]}}.
     {test_heap,6,1}.
 -    {put_list,{x,0},nil,{x,1}}.
 -    {put_tuple,3,{x,0}}.
 -    {put,{y,0}}.
 -    {put,{atom,x}}.
 -    {put,{x,1}}.
 +    {put_list,{x,0},nil,{x,0}}.
 +    {put_tuple2,{x,0},{list,[{y,0},{atom,x},{x,0}]}}.
     {deallocate,1}.
     return.


 -{function, rev, 0, 214}.
 -  {label,213}.
 +{function, rev, 0, 187}.
 +  {label,186}.
     {line,[{location,"couch_key_tree.erl",627}]}.
     {func_info,{atom,couch_key_tree},{atom,rev},0}.
 -  {label,214}.
 +  {label,187}.
     {move,{integer,16},{x,0}}.
     {line,[{location,"couch_key_tree.erl",628}]}.
     {call_ext_only,1,{extfunc,crypto,strong_rand_bytes,1}}.


 -{function, dt, 2, 216}.
 -  {label,215}.
 +{function, dt, 2, 189}.
 +  {label,188}.
     {line,[{location,"couch_key_tree.erl",630}]}.
     {func_info,{atom,couch_key_tree},{atom,dt},2}.
 -  {label,216}.
 +  {label,189}.
     {line,[{location,"couch_key_tree.erl",631}]}.
     {gc_bif,'-',{f,0},2,[{x,0},{x,1}],{x,0}}.
     {move,{atom,second},{x,2}}.
 @@ -2534,224 +2789,214 @@
     {call_ext_only,3,{extfunc,erlang,convert_time_unit,3}}.


 -{function, mem_mb, 1, 218}.
 -  {label,217}.
 +{function, mem_mb, 1, 191}.
 +  {label,190}.
     {line,[{location,"couch_key_tree.erl",633}]}.
     {func_info,{atom,couch_key_tree},{atom,mem_mb},1}.
 -  {label,218}.
 +  {label,191}.
     {allocate,0,1}.
     {move,{atom,memory},{x,1}}.
     {line,[{location,"couch_key_tree.erl",634}]}.
     {call_ext,2,{extfunc,erlang,process_info,2}}.
 -    {test,is_tagged_tuple,{f,219},[{x,0},2,{atom,memory}]}.
 -    {move,nil,{x,1}}.
 -    {get_tuple_element,{x,0},1,{x,2}}.
 +    {test,is_tagged_tuple,{f,192},[{x,0},2,{atom,memory}]}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
     {line,[{location,"couch_key_tree.erl",635}]}.
 -    {gc_bif,'*',{f,0},3,[{x,2},{integer,8}],{x,0}}.
 -    {test_heap,{alloc,[{words,0},{floats,1}]},1}.
 +    {gc_bif,'*',{f,0},1,[{x,0},{integer,8}],{x,0}}.
 +    fclearerror.
     {line,[{location,"couch_key_tree.erl",636}]}.
     {fconv,{x,0},{fr,0}}.
     {fmove,{float,1048576.0},{fr,1}}.
 -    fclearerror.
 +    {line,[{location,"couch_key_tree.erl",636}]}.
     {bif,fdiv,{f,0},[{fr,0},{fr,1}],{fr,0}}.
     {fcheckerror,{f,0}}.
 +    {test_heap,{alloc,[{words,0},{floats,1}]},0}.
     {fmove,{fr,0},{x,0}}.
     {deallocate,0}.
     return.
 -  {label,219}.
 +  {label,192}.
     {line,[{location,"couch_key_tree.erl",634}]}.
     {badmatch,{x,0}}.


 -{function, get_max_mem, 1, 221}.
 -  {label,220}.
 +{function, get_max_mem, 1, 194}.
 +  {label,193}.
     {line,[{location,"couch_key_tree.erl",638}]}.
     {func_info,{atom,couch_key_tree},{atom,get_max_mem},1}.
 -  {label,221}.
 +  {label,194}.
     {allocate_heap,0,3,1}.
     {bif,self,{f,0},[],{x,1}}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{atom,get_mem}}.
 -    {put,{x,1}}.
 -    {move,{x,2},{x,1}}.
 +    {put_tuple2,{x,1},{list,[{atom,get_mem},{x,1}]}}.
     {line,[{location,"couch_key_tree.erl",639}]}.
     send.
 -    {line,[{location,"couch_key_tree.erl",640}]}.
 -  {label,222}.
 -    {loop_rec,{f,224},{x,0}}.
 -    {test,is_tagged_tuple,{f,223},[{x,0},2,{atom,mem_max}]}.
 +  {label,195}.
 +    {loop_rec,{f,197},{x,0}}.
 +    {test,is_tagged_tuple,{f,196},[{x,0},2,{atom,mem_max}]}.
     {get_tuple_element,{x,0},1,{x,0}}.
     remove_message.
     {deallocate,0}.
     return.
 -  {label,223}.
 -    {loop_rec_end,{f,222}}.
 -  {label,224}.
 -    {wait,{f,222}}.
 +  {label,196}.
 +    {loop_rec_end,{f,195}}.
 +  {label,197}.
 +    {wait,{f,195}}.


 -{function, spawn_mem_sampler, 2, 226}.
 -  {label,225}.
 +{function, spawn_mem_sampler, 2, 199}.
 +  {label,198}.
     {line,[{location,"couch_key_tree.erl",642}]}.
     {func_info,{atom,couch_key_tree},{atom,spawn_mem_sampler},2}.
 -  {label,226}.
 -    {move,{x,1},{x,2}}.
 -    {move,{x,0},{x,1}}.
 -    {move,{x,2},{x,0}}.
 -    {make_fun2,{f,238},0,0,2}.
 +  {label,199}.
 +    {'%',{var_info,{x,1},[{type,{t_integer,{500,500}}}]}}.
 +    {make_fun2,{f,211},0,0,2}.
 +    {'%',{var_info,{x,0},[{fun_type,none}]}}.
     {line,[{location,"couch_key_tree.erl",643}]}.
     {call_ext_only,1,{extfunc,erlang,spawn_link,1}}.


 -{function, mem_sampler, 3, 228}.
 -  {label,227}.
 +{function, mem_sampler, 3, 201}.
 +  {label,200}.
     {line,[{location,"couch_key_tree.erl",645}]}.
     {func_info,{atom,couch_key_tree},{atom,mem_sampler},3}.
 -  {label,228}.
 -    {allocate,3,3}.
 -    {move,{x,0},{y,2}}.
 +  {label,201}.
 +    {'%',{var_info,{x,1},[{type,{t_integer,{500,500}}}]}}.
 +    {allocate,2,3}.
     {move,{x,2},{y,0}}.
 -    {move,{x,1},{y,1}}.
 -    {move,{x,1},{x,0}}.
 +    {move,{x,0},{y,1}}.
 +    {move,{integer,500},{x,0}}.
     {line,[{location,"couch_key_tree.erl",646}]}.
     {call_ext,1,{extfunc,timer,sleep,1}}.
 -    {move,{y,2},{x,0}}.
 +    {move,{y,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",647}]}.
 -    {call,1,{f,218}}.
 +    {call,1,{f,191}}.
 +    {'%',{var_info,{x,0},[{type,{t_float,any}}]}}.
     {move,{y,0},{x,1}}.
     {kill,{y,0}}.
 -    {line,[{location,"couch_key_tree.erl",647}]}.
     {call_ext,2,{extfunc,erlang,max,2}}.
     {move,{x,0},{y,0}}.
 -    {line,[{location,"couch_key_tree.erl",648}]}.
 -  {label,229}.
 -    {loop_rec,{f,231},{x,0}}.
 -    {test,is_tagged_tuple,{f,230},[{x,0},2,{atom,get_mem}]}.
 +  {label,202}.
 +    {loop_rec,{f,204},{x,0}}.
 +    {test,is_tagged_tuple,{f,203},[{x,0},2,{atom,get_mem}]}.
     {test_heap,3,1}.
 -    {get_tuple_element,{x,0},1,{x,0}}.
     remove_message.
 -    {put_tuple,2,{x,1}}.
 -    {put,{atom,mem_max}}.
 -    {put,{y,0}}.
 +    {put_tuple2,{x,1},{list,[{atom,mem_max},{y,0}]}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
     {line,[{location,"couch_key_tree.erl",650}]}.
     send.
 -    {jump,{f,232}}.
 -  {label,230}.
 -    {loop_rec_end,{f,229}}.
 -  {label,231}.
 +    {jump,{f,205}}.
 +  {label,203}.
 +    {loop_rec_end,{f,202}}.
 +  {label,204}.
     timeout.
 -  {label,232}.
 -    {move,{y,1},{x,1}}.
 +  {label,205}.
 +    {move,{integer,500},{x,1}}.
     {move,{y,0},{x,2}}.
 -    {move,{y,2},{x,0}}.
 -    {call_last,3,{f,228},3}.
 +    {move,{y,1},{x,0}}.
 +    {call_last,3,{f,201},2}.


 -{function, module_info, 0, 234}.
 -  {label,233}.
 +{function, module_info, 0, 207}.
 +  {label,206}.
     {line,[]}.
     {func_info,{atom,couch_key_tree},{atom,module_info},0}.
 -  {label,234}.
 +  {label,207}.
     {move,{atom,couch_key_tree},{x,0}}.
     {line,[]}.
     {call_ext_only,1,{extfunc,erlang,get_module_info,1}}.


 -{function, module_info, 1, 236}.
 -  {label,235}.
 +{function, module_info, 1, 209}.
 +  {label,208}.
     {line,[]}.
     {func_info,{atom,couch_key_tree},{atom,module_info},1}.
 -  {label,236}.
 +  {label,209}.
     {move,{x,0},{x,1}}.
     {move,{atom,couch_key_tree},{x,0}}.
     {line,[]}.
     {call_ext_only,2,{extfunc,erlang,get_module_info,2}}.


 -{function, '-spawn_mem_sampler/2-fun-0-', 2, 238}.
 -  {label,237}.
 +{function, '-spawn_mem_sampler/2-fun-0-', 2, 211}.
 +  {label,210}.
     {line,[{location,"couch_key_tree.erl",643}]}.
     {func_info,{atom,couch_key_tree},{atom,'-spawn_mem_sampler/2-fun-0-'},2}.
 -  {label,238}.
 -    {allocate,2,2}.
 +  {label,211}.
 +    {'%',{var_info,{x,1},[{type,{t_integer,{500,500}}}]}}.
 +    {allocate,1,1}.
     {move,{x,0},{y,0}}.
 -    {move,{x,1},{y,1}}.
 -    {move,{x,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",643}]}.
 -    {call,1,{f,218}}.
 -    {move,{y,0},{x,1}}.
 +    {call,1,{f,191}}.
 +    {'%',{var_info,{x,0},[{type,{t_float,any}}]}}.
 +    {move,{integer,500},{x,1}}.
     {move,{x,0},{x,2}}.
 -    {move,{y,1},{x,0}}.
 -    {call_last,3,{f,228},2}.
 +    {move,{y,0},{x,0}}.
 +    {call_last,3,{f,201},1}.


 -{function, '-repair_tree/2-fun-2-', 2, 240}.
 -  {label,239}.
 +{function, '-repair_tree/2-fun-2-', 2, 213}.
 +  {label,212}.
     {line,[{location,"couch_key_tree.erl",546}]}.
     {func_info,{atom,couch_key_tree},{atom,'-repair_tree/2-fun-2-'},2}.
 -  {label,240}.
 -    {test,is_tuple,{f,239},[{x,0}]}.
 -    {test,test_arity,{f,239},[{x,0},2]}.
 +  {label,213}.
 +    {test,is_tuple,{f,212},[{x,0}]}.
 +    {test,test_arity,{f,212},[{x,0},2]}.
     {allocate,3,2}.
 -    {get_tuple_element,{x,0},0,{y,2}}.
 -    {get_tuple_element,{x,0},1,{y,0}}.
 -    {move,{x,1},{y,1}}.
 -    {make_fun2,{f,244},0,0,0}.
 -    {move,{y,0},{x,2}}.
 +    {move,{x,0},{y,1}}.
 +    {move,{x,1},{y,2}}.
 +    {get_tuple_element,{x,0},0,{y,0}}.
 +    {make_fun2,{f,216},0,0,0}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_cons,{t_tuple,3,true,#{}},nil}}]}}.
 +    {get_tuple_element,{y,1},1,{x,2}}.
     {move,nil,{x,1}}.
 +    {move,{y,0},{y,1}}.
     {trim,1,2}.
     {line,[{location,"couch_key_tree.erl",547}]}.
     {call_ext,3,{extfunc,lists,foldl,3}}.
 -    {test,is_nonempty_list,{f,242},[{x,0}]}.
 +    {test,is_nonempty_list,{f,214},[{x,0}]}.
     {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_nil,{f,242},[{x,2}]}.
 +    {test,is_nil,{f,214},[{x,2}]}.
     {test_heap,3,2}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{y,1}}.
 -    {put,{x,1}}.
 -    {move,{x,2},{x,1}}.
 -    {move,{y,0},{x,0}}.
 +    {put_tuple2,{x,1},{list,[{y,0},{x,1}]}}.
 +    {move,{y,1},{x,0}}.
     {trim,2,0}.
     {line,[{location,"couch_key_tree.erl",550}]}.
     {call,2,{f,4}}.
 -    {test,is_tuple,{f,241},[{x,0}]}.
 -    {test,test_arity,{f,241},[{x,0},2]}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 => {t_list,any,nil},
 +                       2 => {t_atom,[internal_node,new_branch,new_leaf]}}}}]}}.
     {get_tuple_element,{x,0},0,{x,0}}.
     {deallocate,0}.
     return.
 -  {label,241}.
 -    {line,[{location,"couch_key_tree.erl",550}]}.
 -    {badmatch,{x,0}}.
 -  {label,242}.
 +  {label,214}.
     {line,[{location,"couch_key_tree.erl",547}]}.
     {badmatch,{x,0}}.


 -{function, '-repair_tree/2-fun-1-', 2, 244}.
 -  {label,243}.
 +{function, '-repair_tree/2-fun-1-', 2, 216}.
 +  {label,215}.
     {line,[{location,"couch_key_tree.erl",548}]}.
     {func_info,{atom,couch_key_tree},{atom,'-repair_tree/2-fun-1-'},2}.
 -  {label,244}.
 -    {test,is_tuple,{f,243},[{x,0}]}.
 -    {test,test_arity,{f,243},[{x,0},2]}.
 +  {label,216}.
 +    {test,is_tuple,{f,215},[{x,0}]}.
 +    {test,test_arity,{f,215},[{x,0},2]}.
     {test_heap,6,2}.
     {get_tuple_element,{x,0},0,{x,2}}.
 -    {get_tuple_element,{x,0},1,{x,3}}.
 -    {put_tuple,3,{x,4}}.
 -    {put,{x,2}}.
 -    {put,{x,3}}.
 -    {put,{x,1}}.
 -    {put_list,{x,4},nil,{x,0}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,2},{x,0},{x,1}]}}.
 +    {put_list,{x,0},nil,{x,0}}.
     return.


 -{function, '-repair_tree/2-fun-0-', 2, 246}.
 -  {label,245}.
 +{function, '-repair_tree/2-fun-0-', 2, 218}.
 +  {label,217}.
     {line,[{location,"couch_key_tree.erl",536}]}.
     {func_info,{atom,couch_key_tree},{atom,'-repair_tree/2-fun-0-'},2}.
 -  {label,246}.
 -    {test,is_tuple,{f,247},[{x,0}]}.
 -    {test,test_arity,{f,247},[{x,0},2]}.
 +  {label,218}.
 +    {test,is_tuple,{f,219},[{x,0}]}.
 +    {test,test_arity,{f,219},[{x,0},2]}.
     {allocate,1,2}.
     {get_tuple_element,{x,0},0,{y,0}}.
     {get_tuple_element,{x,0},1,{x,0}}.
 @@ -2764,162 +3009,134 @@
     {line,[{location,"couch_key_tree.erl",538}]}.
     {gc_bif,'-',{f,0},3,[{x,1},{x,2}],{x,1}}.
     {test_heap,3,2}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{x,1}}.
 -    {put,{x,0}}.
 -    {move,{x,2},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,1}.
     return.
 -  {label,247}.
 +  {label,219}.
     {test_heap,2,1}.
     {put_list,{x,0},nil,{x,1}}.
     {move,{atom,function_clause},{x,0}}.
     {line,[{location,"couch_key_tree.erl",536}]}.
 -    {call_ext,2,{extfunc,erlang,error,2}}.
 +    {call_ext_only,2,{extfunc,erlang,error,2}}.


 -{function, '-stem_tree/4-fun-1-', 2, 249}.
 -  {label,248}.
 +{function, '-stem_tree/4-fun-1-', 2, 221}.
 +  {label,220}.
     {line,[{location,"couch_key_tree.erl",514}]}.
     {func_info,{atom,couch_key_tree},{atom,'-stem_tree/4-fun-1-'},2}.
 -  {label,249}.
 +  {label,221}.
     {line,[{location,"couch_key_tree.erl",515}]}.
     {gc_bif,'+',{f,0},2,[{x,1},{integer,1}],{x,1}}.
     {test_heap,3,2}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{x,1}}.
 -    {put,{x,0}}.
 -    {move,{x,2},{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     return.


 -{function, '-stem_tree/4-fun-0-', 4, 251}.
 -  {label,250}.
 +{function, '-stem_tree/4-fun-0-', 4, 223}.
 +  {label,222}.
     {line,[{location,"couch_key_tree.erl",490}]}.
     {func_info,{atom,couch_key_tree},{atom,'-stem_tree/4-fun-0-'},4}.
 -  {label,251}.
 -    {test,is_tuple,{f,255},[{x,1}]}.
 -    {test,test_arity,{f,255},[{x,1},4]}.
 -    {allocate_zero,5,4}.
 -    {get_tuple_element,{x,1},0,{x,4}}.
 -    {get_tuple_element,{x,1},1,{x,5}}.
 -    {get_tuple_element,{x,1},2,{x,6}}.
 -    {get_tuple_element,{x,1},3,{x,7}}.
 +  {label,223}.
 +    {test,is_tuple,{f,227},[{x,1}]}.
 +    {test,test_arity,{f,227},[{x,1},4]}.
     {line,[{location,"couch_key_tree.erl",492}]}.
 -    {gc_bif,'+',{f,0},8,[{x,3},{integer,1}],{x,8}}.
 -    {move,{x,4},{x,3}}.
 -    {move,{x,0},{x,1}}.
 -    {move,{x,7},{y,2}}.
 -    {move,{x,6},{y,3}}.
 -    {move,{x,5},{y,4}}.
 -    {move,{x,8},{x,0}}.
 +    {gc_bif,'+',{f,0},4,[{x,2},{integer,1}],{x,2}}.
 +    {allocate_zero,3,4}.
 +    {move,{x,1},{y,2}}.
 +    {get_tuple_element,{x,1},0,{x,1}}.
 +    {swap,{x,3},{x,2}}.
 +    {swap,{x,1},{x,3}}.
 +    {swap,{x,0},{x,1}}.
     {line,[{location,"couch_key_tree.erl",492}]}.
 -    {call,4,{f,175}}.
 -    {test,is_tuple,{f,254},[{x,0}]}.
 -    {select_tuple_arity,{x,0},{f,254},{list,[4,{f,252},3,{f,253}]}}.
 -  {label,252}.
 -    {get_tuple_element,{x,0},2,{y,0}}.
 -    {get_tuple_element,{x,0},3,{y,1}}.
 -    {move,{y,4},{x,1}}.
 -    {get_tuple_element,{x,0},0,{y,4}}.
 +    {call,4,{f,148}}.
 +    {'%',{var_info,{x,0},[{type,{t_tuple,3,false,#{2 => number}}}]}}.
 +    {get_tuple_element,{y,2},1,{x,1}}.
 +    {get_tuple_element,{y,2},2,{y,1}}.
 +    {get_tuple_element,{y,2},3,{y,2}}.
 +    {move,{x,0},{y,0}}.
 +    {select_tuple_arity,{x,0},{f,226},{list,[3,{f,225},4,{f,224}]}}.
 +  {label,224}.
     {get_tuple_element,{x,0},1,{x,0}}.
 -    {line,[{location,"couch_key_tree.erl",494}]}.
     {call_ext,2,{extfunc,erlang,max,2}}.
     {test_heap,2,1}.
 -    {put_list,{y,0},{y,3},{y,0}}.
 -    {move,{x,0},{y,3}}.
 -    {move,{y,2},{x,1}}.
 -    {move,{y,1},{x,0}}.
 -    {kill,{y,1}}.
 -    {kill,{y,2}}.
 +    {get_tuple_element,{y,0},2,{x,1}}.
 +    {put_list,{x,1},{y,1},{y,1}}.
 +    {get_tuple_element,{y,0},3,{x,1}}.
 +    {move,{y,2},{x,2}}.
 +    {move,{x,0},{y,2}}.
 +    {move,{x,1},{x,0}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",496}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,5,1}.
 -    {put_tuple,4,{x,1}}.
 -    {put,{y,4}}.
 -    {put,{y,3}}.
 -    {put,{y,0}}.
 -    {put,{x,0}}.
 -    {move,{x,1},{x,0}}.
 -    {deallocate,5}.
 +    {get_tuple_element,{y,0},0,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{y,2},{y,1},{x,0}]}}.
 +    {deallocate,3}.
     return.
 -  {label,253}.
 -    {get_tuple_element,{x,0},2,{y,1}}.
 -    {move,{y,4},{x,1}}.
 -    {get_tuple_element,{x,0},0,{y,4}}.
 +  {label,225}.
     {get_tuple_element,{x,0},1,{x,0}}.
 -    {line,[{location,"couch_key_tree.erl",499}]}.
     {call_ext,2,{extfunc,erlang,max,2}}.
 -    {move,{x,0},{x,2}}.
 -    {move,{y,2},{x,1}}.
 -    {move,{x,2},{y,2}}.
 -    {move,{y,1},{x,0}}.
 -    {trim,2,3}.
 +    {get_tuple_element,{y,0},2,{x,1}}.
 +    {move,{y,2},{x,2}}.
 +    {move,{x,0},{y,2}}.
 +    {move,{x,1},{x,0}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",500}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,5,1}.
 -    {put_tuple,4,{x,1}}.
 -    {put,{y,2}}.
 -    {put,{y,0}}.
 -    {put,{y,1}}.
 -    {put,{x,0}}.
 -    {move,{x,1},{x,0}}.
 +    {get_tuple_element,{y,0},0,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{y,2},{y,1},{x,0}]}}.
     {deallocate,3}.
     return.
 -  {label,254}.
 +  {label,226}.
     {line,[{location,"couch_key_tree.erl",492}]}.
     {case_end,{x,0}}.
 -  {label,255}.
 +  {label,227}.
     {line,[{location,"couch_key_tree.erl",491}]}.
     {badmatch,{x,1}}.


 -{function, '-stem/2-fun-0-', 3, 257}.
 -  {label,256}.
 +{function, '-stem/2-fun-0-', 3, 229}.
 +  {label,228}.
     {line,[{location,"couch_key_tree.erl",464}]}.
     {func_info,{atom,couch_key_tree},{atom,'-stem/2-fun-0-'},3}.
 -  {label,257}.
 -    {test,is_tuple,{f,259},[{x,1}]}.
 -    {test,test_arity,{f,259},[{x,1},2]}.
 +  {label,229}.
 +    {test,is_tuple,{f,230},[{x,1}]}.
 +    {test,test_arity,{f,230},[{x,1},2]}.
     {allocate,1,3}.
     {get_tuple_element,{x,1},0,{x,3}}.
     {get_tuple_element,{x,1},1,{y,0}}.
     {move,{x,2},{x,1}}.
     {move,{x,3},{x,2}}.
     {line,[{location,"couch_key_tree.erl",465}]}.
 -    {call,3,{f,170}}.
 -    {test,is_tuple,{f,258},[{x,0}]}.
 -    {test,test_arity,{f,258},[{x,0},2]}.
 -    {get_tuple_element,{x,0},0,{x,3}}.
 -    {get_tuple_element,{x,0},1,{x,0}}.
 -    {move,{y,0},{x,1}}.
 -    {move,{x,3},{y,0}}.
 +    {call,3,{f,143}}.
 +    {'%',{var_info,{x,0},[{type,{t_tuple,2,true,#{}}}]}}.
 +    {get_tuple_element,{x,0},1,{x,1}}.
 +    {move,{y,0},{x,2}}.
 +    {move,{x,0},{y,0}}.
 +    {move,{x,1},{x,0}}.
 +    {move,{x,2},{x,1}}.
     {line,[{location,"couch_key_tree.erl",466}]}.
     {call_ext,2,{extfunc,erlang,'++',2}}.
     {test_heap,3,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,0}}.
 -    {put,{x,0}}.
 -    {move,{x,1},{x,0}}.
 +    {get_tuple_element,{y,0},0,{x,1}}.
 +    {put_tuple2,{x,0},{list,[{x,1},{x,0}]}}.
     {deallocate,1}.
     return.
 -  {label,258}.
 -    {line,[{location,"couch_key_tree.erl",465}]}.
 -    {badmatch,{x,0}}.
 -  {label,259}.
 +  {label,230}.
     {test_heap,4,2}.
 -    {put_list,{x,1},nil,{x,2}}.
 -    {put_list,{x,0},{x,2},{x,1}}.
 +    {put_list,{x,1},nil,{x,1}}.
 +    {put_list,{x,0},{x,1},{x,1}}.
     {move,{atom,function_clause},{x,0}}.
     {line,[{location,"couch_key_tree.erl",464}]}.
 -    {call_ext,2,{extfunc,erlang,error,2}}.
 +    {call_ext_only,2,{extfunc,erlang,error,2}}.


 -{function, '-map/2-fun-0-', 4, 261}.
 -  {label,260}.
 +{function, '-map/2-fun-0-', 4, 232}.
 +  {label,231}.
     {line,[{location,"couch_key_tree.erl",404}]}.
     {func_info,{atom,couch_key_tree},{atom,'-map/2-fun-0-'},4}.
 -  {label,261}.
 +  {label,232}.
     {allocate,0,4}.
     {move,{x,3},{x,2}}.
     {line,[{location,"couch_key_tree.erl",404}]}.
 @@ -2928,330 +3145,322 @@
     return.


 -{function, '-get/2-lc$^0/1-0-', 1, 263}.
 -  {label,262}.
 +{function, '-get/2-lc$^0/1-0-', 1, 234}.
 +  {label,233}.
     {line,[{location,"couch_key_tree.erl",301}]}.
     {func_info,{atom,couch_key_tree},{atom,'-get/2-lc$^0/1-0-'},1}.
 -  {label,263}.
 -    {test,is_nonempty_list,{f,265},[{x,0}]}.
 -    {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_tuple,{f,264},[{x,1}]}.
 -    {test,test_arity,{f,264},[{x,1},2]}.
 -    {get_tuple_element,{x,1},0,{x,3}}.
 -    {get_tuple_element,{x,1},1,{x,4}}.
 -    {test,is_nonempty_list,{f,264},[{x,4}]}.
 -    {get_hd,{x,4},{x,5}}.
 -    {test,is_tuple,{f,264},[{x,5}]}.
 -    {test,test_arity,{f,264},[{x,5},2]}.
 -    {allocate,3,6}.
 -    {get_tuple_element,{x,5},1,{y,2}}.
 -    {move,{x,2},{y,0}}.
 -    {move,{x,3},{y,1}}.
 -    {move,{x,4},{x,0}}.
 +  {label,234}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                     nil}}]}}.
 +    {test,is_nonempty_list,{f,236},[{x,0}]}.
 +    {get_list,{x,0},{x,1},{x,0}}.
 +    {get_tuple_element,{x,1},0,{x,2}}.
 +    {get_tuple_element,{x,1},1,{x,1}}.
 +    {get_hd,{x,1},{x,3}}.
 +    {test,test_arity,{f,235},[{x,3},2]}.
 +    {allocate,3,4}.
 +    {move,{x,3},{y,0}}.
 +    {move,{x,2},{y,1}}.
 +    {move,{x,0},{y,2}}.
 +    {move,{x,1},{x,0}}.
     {line,[{location,"couch_key_tree.erl",300}]}.
 -    {call,1,{f,267}}.
 -    {move,{x,0},{x,1}}.
 -    {move,{y,0},{x,0}}.
 -    {move,{x,1},{y,0}}.
 +    {call,1,{f,238}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,any,nil}}]}}.
 +    {swap,{y,2},{x,0}}.
     {line,[{location,"couch_key_tree.erl",301}]}.
 -    {call,1,{f,263}}.
 +    {call,1,{f,234}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_tuple,2,true,#{2 => {t_list,any,nil}}}}},
 +                     nil}}]}}.
     {test_heap,8,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,1}}.
 -    {put,{y,0}}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{y,2}}.
 -    {put,{x,1}}.
 -    {put_list,{x,2},{x,0},{x,0}}.
 +    {get_tuple_element,{y,0},1,{x,1}}.
 +    {put_tuple2,{x,2},{list,[{y,1},{y,2}]}}.
 +    {put_tuple2,{x,1},{list,[{x,1},{x,2}]}}.
 +    {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,3}.
     return.
 -  {label,264}.
 -    {move,{x,2},{x,0}}.
 -    {call_only,1,{f,263}}.
 -  {label,265}.
 -    {test,is_nil,{f,262},[{x,0}]}.
 +  {label,235}.
 +    {call_only,1,{f,234}}.
 +  {label,236}.
     return.


 -{function, '-get/2-lc$^1/1-1-', 1, 267}.
 -  {label,266}.
 +{function, '-get/2-lc$^1/1-1-', 1, 238}.
 +  {label,237}.
     {line,[{location,"couch_key_tree.erl",300}]}.
     {func_info,{atom,couch_key_tree},{atom,'-get/2-lc$^1/1-1-'},1}.
 -  {label,267}.
 -    {test,is_nonempty_list,{f,269},[{x,0}]}.
 -    {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_tuple,{f,268},[{x,1}]}.
 -    {test,test_arity,{f,268},[{x,1},2]}.
 -    {allocate,1,3}.
 -    {get_tuple_element,{x,1},0,{y,0}}.
 -    {move,{x,2},{x,0}}.
 +  {label,238}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,0,false,#{}},nil}}]}}.
 +    {test,is_nonempty_list,{f,240},[{x,0}]}.
 +    {get_list,{x,0},{x,1},{x,0}}.
 +    {test,test_arity,{f,239},[{x,1},2]}.
 +    {allocate,1,2}.
 +    {move,{x,1},{y,0}}.
     {line,[{location,"couch_key_tree.erl",300}]}.
 -    {call,1,{f,267}}.
 +    {call,1,{f,238}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,any,nil}}]}}.
     {test_heap,2,1}.
 -    {put_list,{y,0},{x,0},{x,0}}.
 +    {get_tuple_element,{y,0},0,{x,1}}.
 +    {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,1}.
     return.
 -  {label,268}.
 -    {move,{x,2},{x,0}}.
 -    {call_only,1,{f,267}}.
 -  {label,269}.
 -    {test,is_nil,{f,266},[{x,0}]}.
 +  {label,239}.
 +    {call_only,1,{f,238}}.
 +  {label,240}.
     return.


 -{function, '-remove_leafs/2-fun-2-', 2, 271}.
 -  {label,270}.
 +{function, '-remove_leafs/2-fun-2-', 2, 242}.
 +  {label,241}.
     {line,[{location,"couch_key_tree.erl",230}]}.
     {func_info,{atom,couch_key_tree},{atom,'-remove_leafs/2-fun-2-'},2}.
 -  {label,271}.
 -    {test,is_tuple,{f,270},[{x,0}]}.
 -    {test,test_arity,{f,270},[{x,0},2]}.
 +  {label,242}.
 +    {test,is_tuple,{f,241},[{x,0}]}.
 +    {test,test_arity,{f,241},[{x,0},2]}.
     {allocate,3,2}.
 -    {get_tuple_element,{x,0},0,{y,2}}.
 -    {get_tuple_element,{x,0},1,{y,0}}.
 -    {move,{x,1},{y,1}}.
 -    {make_fun2,{f,275},0,0,0}.
 -    {move,{y,0},{x,2}}.
 +    {move,{x,0},{y,1}}.
 +    {move,{x,1},{y,2}}.
 +    {get_tuple_element,{x,0},0,{y,0}}.
 +    {make_fun2,{f,245},0,0,0}.
 +    {'%',{var_info,{x,0},[{fun_type,{t_cons,{t_tuple,3,true,#{}},nil}}]}}.
 +    {get_tuple_element,{y,1},1,{x,2}}.
     {move,nil,{x,1}}.
 +    {move,{y,0},{y,1}}.
     {trim,1,2}.
     {line,[{location,"couch_key_tree.erl",231}]}.
     {call_ext,3,{extfunc,lists,foldl,3}}.
 -    {test,is_nonempty_list,{f,273},[{x,0}]}.
 +    {test,is_nonempty_list,{f,243},[{x,0}]}.
     {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_nil,{f,273},[{x,2}]}.
 +    {test,is_nil,{f,243},[{x,2}]}.
     {test_heap,3,2}.
 -    {put_tuple,2,{x,2}}.
 -    {put,{y,1}}.
 -    {put,{x,1}}.
 -    {move,{x,2},{x,1}}.
 -    {move,{y,0},{x,0}}.
 +    {put_tuple2,{x,1},{list,[{y,0},{x,1}]}}.
 +    {move,{y,1},{x,0}}.
     {trim,2,0}.
     {line,[{location,"couch_key_tree.erl",234}]}.
     {call,2,{f,4}}.
 -    {test,is_tuple,{f,272},[{x,0}]}.
 -    {test,test_arity,{f,272},[{x,0},2]}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 => {t_list,any,nil},
 +                       2 => {t_atom,[internal_node,new_branch,new_leaf]}}}}]}}.
     {get_tuple_element,{x,0},0,{x,0}}.
     {deallocate,0}.
     return.
 -  {label,272}.
 -    {line,[{location,"couch_key_tree.erl",234}]}.
 -    {badmatch,{x,0}}.
 -  {label,273}.
 +  {label,243}.
     {line,[{location,"couch_key_tree.erl",231}]}.
     {badmatch,{x,0}}.


 -{function, '-remove_leafs/2-fun-1-', 2, 275}.
 -  {label,274}.
 +{function, '-remove_leafs/2-fun-1-', 2, 245}.
 +  {label,244}.
     {line,[{location,"couch_key_tree.erl",232}]}.
     {func_info,{atom,couch_key_tree},{atom,'-remove_leafs/2-fun-1-'},2}.
 -  {label,275}.
 -    {test,is_tuple,{f,274},[{x,0}]}.
 -    {test,test_arity,{f,274},[{x,0},2]}.
 +  {label,245}.
 +    {test,is_tuple,{f,244},[{x,0}]}.
 +    {test,test_arity,{f,244},[{x,0},2]}.
     {test_heap,6,2}.
     {get_tuple_element,{x,0},0,{x,2}}.
 -    {get_tuple_element,{x,0},1,{x,3}}.
 -    {put_tuple,3,{x,4}}.
 -    {put,{x,2}}.
 -    {put,{x,3}}.
 -    {put,{x,1}}.
 -    {put_list,{x,4},nil,{x,0}}.
 +    {get_tuple_element,{x,0},1,{x,0}}.
 +    {put_tuple2,{x,0},{list,[{x,2},{x,0},{x,1}]}}.
 +    {put_list,{x,0},nil,{x,0}}.
     return.


 -{function, '-remove_leafs/2-lc$^0/1-0-', 1, 277}.
 -  {label,276}.
 +{function, '-remove_leafs/2-lc$^0/1-0-', 1, 247}.
 +  {label,246}.
     {line,[{location,"couch_key_tree.erl",225}]}.
     {func_info,{atom,couch_key_tree},{atom,'-remove_leafs/2-lc$^0/1-0-'},1}.
 -  {label,277}.
 -    {test,is_nonempty_list,{f,279},[{x,0}]}.
 -    {get_list,{x,0},{x,1},{x,2}}.
 -    {test,is_tuple,{f,278},[{x,1}]}.
 -    {test,test_arity,{f,278},[{x,1},2]}.
 -    {allocate_zero,2,3}.
 -    {get_tuple_element,{x,1},0,{x,3}}.
 -    {get_tuple_element,{x,1},1,{x,4}}.
 +  {label,247}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                     nil}}]}}.
 +    {test,is_nonempty_list,{f,248},[{x,0}]}.
 +    {get_list,{x,0},{x,1},{x,0}}.
 +    {get_tuple_element,{x,1},0,{x,2}}.
     {line,[{location,"couch_key_tree.erl",225}]}.
 -    {gc_bif,'+',{f,0},5,[{x,3},{integer,1}],{x,0}}.
 +    {gc_bif,'+',{f,0},3,[{x,2},{integer,1}],{x,2}}.
 +    {get_tuple_element,{x,1},1,{x,1}}.
     {line,[{location,"couch_key_tree.erl",225}]}.
 -    {gc_bif,length,{f,0},5,[{x,4}],{x,1}}.
 +    {gc_bif,length,{f,0},3,[{x,1}],{x,3}}.
     {line,[{location,"couch_key_tree.erl",225}]}.
 -    {gc_bif,'-',{f,0},5,[{x,0},{x,1}],{y,0}}.
 -    {move,{x,4},{y,1}}.
 -    {move,{x,2},{x,0}}.
 +    {gc_bif,'-',{f,0},4,[{x,2},{x,3}],{x,2}}.
 +    {allocate,2,3}.
 +    {move,{x,1},{y,0}}.
 +    {move,{x,2},{y,1}}.
     {line,[{location,"couch_key_tree.erl",225}]}.
 -    {call,1,{f,277}}.
 +    {call,1,{f,247}}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_list,
 +                     {t_tuple,2,true,
 +                         #{1 => number,
 +                           2 => {t_cons,{t_tuple,0,false,#{}},nil}}},
 +                     nil}}]}}.
     {test_heap,5,1}.
 -    {put_tuple,2,{x,1}}.
 -    {put,{y,0}}.
 -    {put,{y,1}}.
 +    {put_tuple2,{x,1},{list,[{y,1},{y,0}]}}.
     {put_list,{x,1},{x,0},{x,0}}.
     {deallocate,2}.
     return.
 -  {label,278}.
 -    {move,{x,2},{x,0}}.
 -    {call_only,1,{f,277}}.
 -  {label,279}.
 -    {test,is_nil,{f,276},[{x,0}]}.
 +  {label,248}.
     return.


 -{function, '-find_missing_simple/3-lc$^1/1-1-', 2, 281}.
 -  {label,280}.
 +{function, '-find_missing_simple/3-lc$^1/1-1-', 2, 250}.
 +  {label,249}.
     {line,[{location,"couch_key_tree.erl",197}]}.
     {func_info,{atom,couch_key_tree},
                {atom,'-find_missing_simple/3-lc$^1/1-1-'},
                2}.
 -  {label,281}.
 -    {test,is_nonempty_list,{f,283},[{x,0}]}.
 -    {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,282},[{x,2}]}.
 -    {test,test_arity,{f,282},[{x,2},2]}.
 -    {get_tuple_element,{x,2},0,{x,4}}.
 -    {test,is_lt,{f,282},[{x,4},{x,1}]}.
 -    {allocate,1,4}.
 +  {label,250}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {test,is_nonempty_list,{f,252},[{x,0}]}.
 +    {get_list,{x,0},{x,2},{x,0}}.
 +    {get_tuple_element,{x,2},0,{x,3}}.
 +    {test,is_lt,{f,251},[{x,3},{x,1}]}.
 +    {allocate,1,3}.
     {move,{x,2},{y,0}}.
 -    {move,{x,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",197}]}.
 -    {call,2,{f,281}}.
 +    {call,2,{f,250}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {test_heap,2,1}.
     {put_list,{y,0},{x,0},{x,0}}.
     {deallocate,1}.
     return.
 -  {label,282}.
 -    {move,{x,3},{x,0}}.
 -    {call_only,2,{f,281}}.
 -  {label,283}.
 -    {test,is_nil,{f,284},[{x,0}]}.
 +  {label,251}.
 +    {call_only,2,{f,250}}.
 +  {label,252}.
     return.
 -  {label,284}.
 -    {test_heap,2,1}.
 -    {put_list,{x,0},nil,{x,1}}.
 -    {move,{atom,function_clause},{x,0}}.
 -    {line,[{location,"couch_key_tree.erl",197}]}.
 -    {call_ext,2,{extfunc,erlang,error,2}}.


 -{function, '-find_missing_simple/3-lc$^0/1-0-', 2, 286}.
 -  {label,285}.
 +{function, '-find_missing_simple/3-lc$^0/1-0-', 2, 254}.
 +  {label,253}.
     {line,[{location,"couch_key_tree.erl",196}]}.
     {func_info,{atom,couch_key_tree},
                {atom,'-find_missing_simple/3-lc$^0/1-0-'},
                2}.
 -  {label,286}.
 -    {test,is_nonempty_list,{f,288},[{x,0}]}.
 -    {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,287},[{x,2}]}.
 -    {test,test_arity,{f,287},[{x,2},2]}.
 -    {get_tuple_element,{x,2},0,{x,4}}.
 -    {test,is_ge,{f,287},[{x,4},{x,1}]}.
 -    {allocate,1,4}.
 +  {label,254}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
 +    {test,is_nonempty_list,{f,256},[{x,0}]}.
 +    {get_list,{x,0},{x,2},{x,0}}.
 +    {get_tuple_element,{x,2},0,{x,3}}.
 +    {test,is_ge,{f,255},[{x,3},{x,1}]}.
 +    {allocate,1,3}.
     {move,{x,2},{y,0}}.
 -    {move,{x,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",196}]}.
 -    {call,2,{f,286}}.
 +    {call,2,{f,254}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {test_heap,2,1}.
     {put_list,{y,0},{x,0},{x,0}}.
     {deallocate,1}.
     return.
 -  {label,287}.
 -    {move,{x,3},{x,0}}.
 -    {call_only,2,{f,286}}.
 -  {label,288}.
 -    {test,is_nil,{f,289},[{x,0}]}.
 +  {label,255}.
 +    {call_only,2,{f,254}}.
 +  {label,256}.
     return.
 -  {label,289}.
 -    {test_heap,2,1}.
 -    {put_list,{x,0},nil,{x,1}}.
 -    {move,{atom,function_clause},{x,0}}.
 -    {line,[{location,"couch_key_tree.erl",196}]}.
 -    {call_ext,2,{extfunc,erlang,error,2}}.


 -{function, '-find_missing/2-lc$^1/1-1-', 2, 291}.
 -  {label,290}.
 +{function, '-find_missing/2-lc$^1/1-1-', 2, 258}.
 +  {label,257}.
     {line,[{location,"couch_key_tree.erl",187}]}.
     {func_info,{atom,couch_key_tree},{atom,'-find_missing/2-lc$^1/1-1-'},2}.
 -  {label,291}.
 -    {test,is_nonempty_list,{f,293},[{x,0}]}.
 -    {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,292},[{x,2}]}.
 -    {test,test_arity,{f,292},[{x,2},2]}.
 -    {get_tuple_element,{x,2},0,{x,4}}.
 -    {test,is_lt,{f,292},[{x,4},{x,1}]}.
 -    {allocate,1,4}.
 +  {label,258}.
 +    {test,is_nonempty_list,{f,260},[{x,0}]}.
 +    {get_list,{x,0},{x,2},{x,0}}.
 +    {test,is_tuple,{f,259},[{x,2}]}.
 +    {test,test_arity,{f,259},[{x,2},2]}.
 +    {get_tuple_element,{x,2},0,{x,3}}.
 +    {test,is_lt,{f,259},[{x,3},{x,1}]}.
 +    {allocate,1,3}.
     {move,{x,2},{y,0}}.
 -    {move,{x,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",187}]}.
 -    {call,2,{f,291}}.
 +    {call,2,{f,258}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {test_heap,2,1}.
     {put_list,{y,0},{x,0},{x,0}}.
     {deallocate,1}.
     return.
 -  {label,292}.
 -    {move,{x,3},{x,0}}.
 -    {call_only,2,{f,291}}.
 -  {label,293}.
 -    {test,is_nil,{f,294},[{x,0}]}.
 +  {label,259}.
 +    {call_only,2,{f,258}}.
 +  {label,260}.
 +    {test,is_nil,{f,261},[{x,0}]}.
     return.
 -  {label,294}.
 +  {label,261}.
     {test_heap,2,1}.
     {put_list,{x,0},nil,{x,1}}.
     {move,{atom,function_clause},{x,0}}.
     {line,[{location,"couch_key_tree.erl",187}]}.
 -    {call_ext,2,{extfunc,erlang,error,2}}.
 +    {call_ext_only,2,{extfunc,erlang,error,2}}.


 -{function, '-find_missing/2-lc$^0/1-0-', 2, 296}.
 -  {label,295}.
 +{function, '-find_missing/2-lc$^0/1-0-', 2, 263}.
 +  {label,262}.
     {line,[{location,"couch_key_tree.erl",186}]}.
     {func_info,{atom,couch_key_tree},{atom,'-find_missing/2-lc$^0/1-0-'},2}.
 -  {label,296}.
 -    {test,is_nonempty_list,{f,298},[{x,0}]}.
 -    {get_list,{x,0},{x,2},{x,3}}.
 -    {test,is_tuple,{f,297},[{x,2}]}.
 -    {test,test_arity,{f,297},[{x,2},2]}.
 -    {get_tuple_element,{x,2},0,{x,4}}.
 -    {test,is_ge,{f,297},[{x,4},{x,1}]}.
 -    {allocate,1,4}.
 +  {label,263}.
 +    {test,is_nonempty_list,{f,265},[{x,0}]}.
 +    {get_list,{x,0},{x,2},{x,0}}.
 +    {test,is_tuple,{f,264},[{x,2}]}.
 +    {test,test_arity,{f,264},[{x,2},2]}.
 +    {get_tuple_element,{x,2},0,{x,3}}.
 +    {test,is_ge,{f,264},[{x,3},{x,1}]}.
 +    {allocate,1,3}.
     {move,{x,2},{y,0}}.
 -    {move,{x,3},{x,0}}.
     {line,[{location,"couch_key_tree.erl",186}]}.
 -    {call,2,{f,296}}.
 +    {call,2,{f,263}}.
 +    {'%',{var_info,{x,0},[{type,{t_list,{t_tuple,2,true,#{}},nil}}]}}.
     {test_heap,2,1}.
     {put_list,{y,0},{x,0},{x,0}}.
     {deallocate,1}.
     return.
 -  {label,297}.
 -    {move,{x,3},{x,0}}.
 -    {call_only,2,{f,296}}.
 -  {label,298}.
 -    {test,is_nil,{f,299},[{x,0}]}.
 +  {label,264}.
 +    {call_only,2,{f,263}}.
 +  {label,265}.
 +    {test,is_nil,{f,266},[{x,0}]}.
     return.
 -  {label,299}.
 +  {label,266}.
     {test_heap,2,1}.
     {put_list,{x,0},nil,{x,1}}.
     {move,{atom,function_clause},{x,0}}.
     {line,[{location,"couch_key_tree.erl",186}]}.
 -    {call_ext,2,{extfunc,erlang,error,2}}.
 +    {call_ext_only,2,{extfunc,erlang,error,2}}.


 -{function, '-multi_merge/2-fun-0-', 2, 301}.
 -  {label,300}.
 +{function, '-multi_merge/2-fun-0-', 2, 268}.
 +  {label,267}.
     {line,[{location,"couch_key_tree.erl",46}]}.
     {func_info,{atom,couch_key_tree},{atom,'-multi_merge/2-fun-0-'},2}.
 -  {label,301}.
 +  {label,268}.
     {allocate,0,2}.
 -    {move,{x,1},{x,2}}.
 -    {move,{x,0},{x,1}}.
 -    {move,{x,2},{x,0}}.
 +    {swap,{x,0},{x,1}}.
     {line,[{location,"couch_key_tree.erl",47}]}.
     {call,2,{f,4}}.
 -    {test,is_tuple,{f,302},[{x,0}]}.
 -    {test,test_arity,{f,302},[{x,0},2]}.
 +    {'%',
 +        {var_info,
 +            {x,0},
 +            [{type,
 +                 {t_tuple,2,true,
 +                     #{1 => {t_list,any,nil},
 +                       2 => {t_atom,[internal_node,new_branch,new_leaf]}}}}]}}.
     {get_tuple_element,{x,0},0,{x,0}}.
     {deallocate,0}.
     return.
 -  {label,302}.
 -    {line,[{location,"couch_key_tree.erl",47}]}.
 -    {badmatch,{x,0}}.