Add implicitly-declared default and copy constructors to C++ classes,
when appropriate.

Conversions for class types now make use of copy constructors. I've
replaced the egregious hack allowing class-to-class conversions with a
slightly less egregious hack calling these conversions standard
conversions (for overloading reasons).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58622 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed