procedure {:checksum "P1$proc#0"} P1(); // Action: verify implementation {:id "P1"} {:checksum "P1$impl#0"} P1() { call P2(); } procedure {:checksum "P2$proc#1"} P2(); requires false; // Action: verify implementation {:id "P2"} {:checksum "P2$impl#1"} P2() { assert 2 != 2; }