Set Bullet Behavior "Strict Subproofs".
Opaque upto.
Ltac entailer_for_load_tac ::= unfold tc_efield; go_lower; entailer'.
Ltac entailer_for_store_tac ::= unfold tc_efield; go_lower; entailer'.

Lemma body_writer : semax_body Vprog Gprog f_writer writer_spec.