") Proof   rpt strip_tac   \\ fs [evaluate_def,compile_def,flatSemTheory.evaluate_def]   \\ fs [pair_case_eq] \\ fs []   \\ first_x_assum drule   \\ disch_then drule   \\ impl_tac THEN0 (CCONTR_TAC \\ fs [])   \\ strip_tac \\ fs []   \\ fs [result_case_eq] \\ rveq \\ fs []   \\ imp_res_tac evaluate_sing \\ fs [] \\ rveq \\ fs []   \\ 