When dealing with an assignment with LHS being a property reference
expression, the entire assignment tree is rewritten into a property
setter messaging. This includes rewriting the RHS. 
Do not attempt to rewrite RHS again. Never rewrite a rewritten text!
Fixes //rdar: //8527018.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@116104 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed