Move evaluation for expression and result.

[Shylock-Hg]

Is your feature request related to a problem? Please describe.
Reduce the extra result data release and copy.

Describe the solution you'd like
Now we could deduce the lifetime of result(variable), so we could move the out-of-life value instead of copy and release it.
E.G. for expression $-.name + '.xxxx', we will copy $-.name and evaluate expression then release the useless variable $- at now. After this proposal, we will move $-.name and evaluate expression on the moved value, so we eliminate the copy and release cost.

Describe alternatives you've considered

Additional context