Question

assert_severity_task ::=   // not in Annex A
    fatal_message_task
  | nonfatal_message_task

fatal_message_task ::= $fatal[(finish_number[, message_argument{, message_argument}])];

nonfatal_message_task ::= severity_task[([message_argument{, message_argument]}])];

severity_task ::= $error | $warning | $info

finish_number ::= 0 | 1 | 2

message_argument ::= string | expression

Syntax 23-6—Assertion severity system task syntax (not in Annex A)

SystemVerilog assertions have a severity level associated with any assertion failures detected. By default, the severity of an assertion failure is “error”. The severity levels can be specified by including one of the following severity system tasks in the assertion fail statement:

• $fatal shall generate a run-time fatal assertion error, which terminates the simulation with an error code. The first argument passed to $fatal shall be consistent with the corresponding argument to the Verilog $finish system task, which sets the level of diagnostic information reported by the tool. Calling $fatal results in an implicit call to $finish.
• $error shall be a run-time error.
• $warning shall be a run-time warning, which can be suppressed in a tool-specific manner.
• $info shall indicate that the assertion failure carries no specific severity.

All of these severity system tasks shall print a tool-specific message, indicating the severity of the failure, and specific information about the failure, which shall include the following information:

• The file name and line number of the assertion statement,
• The hierarchical name of the assertion, if it is labeled, or the scope of the assertion if it is not labeled.

For simulation tools, these tasks shall also report the simulation run-time at which the severity system task is

called.

Each of the severity tasks can include optional user-defined information to be reported. The user-defined message shall use the same syntax as the Verilog $display system task, and can include any number of arguments.