Add clauses immediately after predicate declaration

[Tragicus]

Hi. It looks like it is not possible to add a clause to a predicate immediately after the creation of the predicate, as the following code shows.

From elpi.apps Require Import tc.

Record C : Prop := {}.

Elpi Query TC.Solver lp:{{

global R = {{ C }},
coq.TC.declare-class R,
coq.elpi.accumulate current "tc.db" (clause _ _ {coq.elpi.predicate {gref->pred-name R} [Build_C]}).

}}.

This fails with the error message

Anomaly
"Uncaught exception Elpi__Compiler.CompileError(0, "allocating new global symbol 'tc-buffer4.tc-C' at runtime")."