First non-embarrassing cut at checking for ambiguous derived-to-base 
conversions.

Added PerformImplicitConversion, which follows an implicit conversion sequence
computed by TryCopyInitialization and actually performs the implicit
conversions, including the extra check for ambiguity mentioned above.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58071 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed