Compute and propagate conversion kind to diagnostics helper in C++
to provide more specific diagnostics about incorrect implicit
conversions in assignments, initializations, params, etc...
Duplicated some diagnostics as errors because C++ is more strict.
Tags: #clang
Differential Revision: https://reviews.llvm.org/D74116
references and isa expressions. Also, test template instantiation of
unresolved member references to Objective-C ivar references and isa
expressions.
llvm-svn: 102374