goal_expansion/2 too deep

[notoria]

I tried:

?- [user].
goal_expansion(g(G), call(G)).

:- dynamic(bad/0).
bad :- g(2).

% Warning: clause body goal expansion failed because 2 is not callable.

?- clause(bad, G).
   G = g(2). % unexpected

I expected G = call(2).

[UWN]

Too nosy...