Activity Chart Checks : (C3011) Elements using uninitialized context variables

(C3011) Elements using uninitialized context variables

Error In:
Correctness
Description:
Elements contain action expressions in which an uninitialized context variable is used.
Example:
A transition has the following label:
E/Y=$X; $X=Z
 
 
$X is used before any value is assigned to it.
Erroneous Elements:
Activities and actions