[PATCH] clang-cl Add support for two MSVC conversion warnings

[Hans Wennborg]

>>! In D6041#9, @ehsan wrote:
>>>! In D6041#7, @hans wrote:
>> Do we really want to try supporting the individual MSVC warning flags?
>> 
>> It will never be a clean mapping anyway, and the diagnostics won't be very nice. For example, Clang won't print the MSVC style warning names when issuing a warning.
>> 
>> Can't you just use the same list of enabled/disabled warning that you use with Clang on other platforms?
> 
> Yeah, I suppose we could do that...  Should we can this patch, then?

I'd be in favor of that.

I think we should certainly support the broad flags, like turning all warnings off, treating them as errors, etc. But for controlling individual Clang warnings, I think it makes sense to use Clang flags.

http://reviews.llvm.org/D6041