Fixpoint varspecs_sub (al bl: varspecs) : bool :=
match al, bl with
| (a,v)::al', (b,w)::bl' =>
    match Pos.compare a b
    with Lt => false
         | Eq => if eqb_type v w then varspecs_sub al' bl' else false
         | Gt => varspecs_sub al' bl
     end
| nil, _ => true
| _::_, _ => false
end.Fixpoint funspecs_sub (al bl: funspecs) : Prop :=
match al, bl with
| (a,v)::al', (b,w)::bl' =>
    match Pos.compare a b
    with Lt => False
         | Eq => v=w /\ funspecs_sub al' bl'
         | Gt => funspecs_sub al' bl
     end
| nil, _ => True
| _::_, _ => False
end.

Lemma semax_func_app: forall V1 V2 V F1 F2 F G1 G2 G G1' G2' G' (Espec: OracleKind), semax_func V1 G1 F1 G1' -> semax_func V2 G2 F2 G2' -> F = F1++F2 -> G' = G1'++G2' -> varspecs_sub V1 V = true -> varspecs_sub V2 V = true -> funspecs_sub G1 G -> funspecs_sub G2 G -> semax_func V G F G'.