This application discloses a computing system to check and generate an assertion statement. The assertion statement, when executed during a simulation of a circuit design, can verify a simulated behavior of the circuit design. The computing system can extract sequence items from the assertion statement, and generate a state representation for the sequence items based on the simulated behavior of the circuit design. The state representation can identify states of the extracted sequence items at different clock ticks of the simulation. The computing system can locate an error in the assertion statement based on the state representation by generating patterns from sequence operators in the assertion statement and comparing the patterns to the state representation. The computing system can utilize the error in the assertion statement to generate a corrected assertion statement. The computing system can utilize propagate-and-repeat functionality to generate assertions by determining when to check each sequence item.