Add some asserts into the common demo tasks to catch scenarios where the tasks are not being used but the part of the demo/test that gets called from the tick hook is called resultant in an access to objects that were not created.

FreeRTOS/Demo/Common/Minimal/EventGroupsDemo.c

@@ -976,6 +976,9 @@ BaseType_t xMessagePosted;
 	/* Called periodically from the tick hook to exercise the "FromISR"
 	functions. */
 
+	/* Check the even group tasks were actually created. */
+	configASSERT( xISREventGroup );
+
 	xCallCount++;
 
 	if( xCallCount == xSetBitCount )

FreeRTOS/Demo/Common/Minimal/TaskNotify.c

@@ -609,6 +609,9 @@ const BaseType_t xCallInterval = pdMS_TO_TICKS( 50 );
 uint32_t ulPreviousValue;
 const uint32_t ulUnexpectedValue = 0xff;
 
+	/* Check the task notification demo tasks were actually created. */
+	configASSERT( xTaskToNotify );
+
 	/* The task performs some tests before starting the timer that gives the
 	notification from this interrupt.  If the timer has not been created yet
 	then the initial tests have not yet completed and the notification should

FreeRTOS/Demo/Common/Minimal/blocktim.c

@@ -478,7 +478,8 @@ const TickType_t xPeriod = 75, xCycles = 5, xAllowableMargin = ( bktALLOWABLE_MA
 	high as to disrupt the timer tests. */
 	vTaskPrioritySet( NULL, configTIMER_TASK_PRIORITY - 1 );
 
-	/* Crude check to too that vTaskDelay() blocks for the expected period. */
+	/* Crude check to too see that vTaskDelay() blocks for the expected
+	period. */
 	xPreTime = xTaskGetTickCount();
 	vTaskDelay( bktTIME_TO_BLOCK );
 	xPostTime = xTaskGetTickCount();