0940			[C] Illegal usage of a variably modified type.
	Constraint violations				REFERENCE - ISO:C99-6.7.5.2 Array declarators - Constraints

• an identifier other than an ordinary identifier (e.g. a struct/union member) is declared with variably modified type, or
• an identifier with variably modified type is declared with external linkage, or
• an array of variable length is declared with static storage duration.

/*PRQA S 2017,3205,3223,3227,3408 ++*/

void foo(int n)
{
    static int arr[n];             /* Message 0940 */
    struct st
    {
        int x;
        int y;
        int buf[n];                /* Message 0940 */
    };
}

MISRA-C:2004 Rules applicable to message 0940: