% COMMAND-LINE: --incremental
x, y: BOOLEAN;
ASSERT x OR y;
% EXPECT: sat
CHECKSAT;
PUSH;
  ASSERT NOT x;
% EXPECT: sat
  CHECKSAT;
  PUSH;
    ASSERT NOT y;
% EXPECT: unsat
    CHECKSAT;
  POP;
% EXPECT: sat
  CHECKSAT;
POP;
% EXPECT: sat
CHECKSAT;