fix for the fix - type constraints for a[b]=c assignments are actually required for the left-hand side when processing Dalvik code. In this case, we need to propagate a' element type to the lhs of the assignment to help the type inference of c.

We however cannot typecast the left-hand side for a=b[c], since a might also be a supertype of b's element type - always forcing it to b's element type is too strong in some cases.