No last without default

No last without default

Description

An assignment just as (last ‘variable -> (L)variable) shall not be used. Only if a default value is assigned such an statement is necessary. Implicit behaviour of SCADE

Rationale

This improves model readability by ensuring that redundant assignments are avoided.

In this case, using the SCADE IDE to set “Last” to “True” on a variable or signal ensures that the previous value is used. There is no need to add an equation writing last 'variable into it.

Verification

The rule registers to equations and raises a violation when the right side of the equation is a variable or signal with “Last” set to “True” and the left side is the same variable or signal.

Message: Assignment (last 'variable -> (L)variable) found (<right_side> -> <left_side>)

Resolution

Remove the redundant equation.

Customization

N/A.