Let Expr::HasSideEffects() return false for NULL, bool literals, this, and nullptr.

Fixes PR13413, -Wunused-private-field now warns on unused fields initialized to NULL.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160541 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed