Ltac extend_tc_prover := 
  match goal with
  | |- _ => solve [immediate]
  | |- _ => apply extend_prop
  | |- _ => first
              [ simple apply extend_tc_bool
              | simple apply extend_tc_int_or_ptr_type
              | simple apply extend_tc_andp
              | simple apply extend_tc_andp'
              | simple apply extend_tc_Zge
              | simple apply extend_tc_Zle
              | simple apply extend_tc_iszero
              | simple apply extend_tc_nonzero
              | simple apply extend_tc_nodivover
              | simple apply extend_tc_nobinover
              | simple apply extend_tc_samebase
              | simple apply extend_tc_ilt
              | simple apply extend_tc_llt
              | simple apply extend_isCastResultType
              | simple apply extend_tc_test_eq
              | simple apply extend_tc_test_order]
  | |- boxy _ (denote_tc_assert (if ?A then _ else _) _) => destruct A
  | |- boxy _ (denote_tc_assert match tc_bool ?A _ with _ => _ end _) =>
             destruct A
  | |- boxy _ (denote_tc_assert match ?A with Some _ => _ | None => _ end _) =>
          destruct A
  end.

Lemma extend_tc_expropt: forall {CS: compspecs} Delta e t rho, boxy extendM (tc_expropt Delta e t rho).