Redundant WAM instructions for inlined goals of meta-predicates

[triska]

Given the following source code:

:- use_module(library(format)).
:- use_module(library(lists)).
:- use_module(library(diag)).

f(a).

fs(Ls) :-
        maplist(f, Ls).

I get:

?- wam_instructions(fs/1, Is), maplist(portray_clause, Is).
put_structure(f,0,x(3)).
set_constant('$index_ptr'(28915)).
get_variable(x(2),1).
put_structure(:,2,x(1)).
set_constant(user).
set_value(x(3)).
execute(maplist,2).

With '$index_ptr'(28915) pointing to the following inlined instructions:

?- inlined_instructions(28915, Is), maplist(portray_clause, Is).
get_constant(level(shallow),a,x(1)).
proceed.

My question: Scryer goes through the extra effort to generate these inlined instructions, and in a sense knows that these instructions are meant when we say maplist(f, ...). At the same time, it also allocates the term user:f on the heap, even though that seems not needed, because we can instead use the inlined goal which is already correctly resolved and compiled.

It seems either one or the other is necessary (i.e., inlined goal or compound term), but not both.

For comparison, GNU Prolog:

predicate(f/1,1,static,private,monofile,global,[
    get_atom(a,0),
    proceed]).

predicate(fs/1,3,static,private,monofile,global,[
    put_value(x(0),1),
    put_atom(f,0),
    execute(maplist/2)]).