Cool - perhaps add a test case for the non-type template parameter case as well? Though it's not really necessary. Up to you.
On Fri, Nov 1, 2013 at 2:54 PM, Richard Trieu <[email protected]> wrote: > Committed in r193887 and r193888 > > > On Fri, Nov 1, 2013 at 1:02 PM, David Blaikie <[email protected]> wrote: > >> >> >> >> On Fri, Nov 1, 2013 at 12:15 PM, Arthur O'Dwyer < >> [email protected]> wrote: >> >>> On Thu, Oct 31, 2013 at 5:52 PM, Richard Trieu <[email protected]> >>> wrote: >>> > On Thu, Oct 31, 2013 at 4:25 PM, David Blaikie <[email protected]> >>> wrote: >>> >> >>> >> Could we just restrict these warnings to only be done on template >>> >> patterns, not template specializations? (I know Ted's had some >>> concern about >>> >> doing work on template patterns in the past because he believed that >>> might >>> >> create too much work analyzing templates that are never instantiated, >>> >> though) >>> > >>> > I think that would be possible and a cleaner way of approaching this. >>> > Currently, Clang warns in both template patters and specializations. >>> That >>> > means if you have : >>> > >>> > template<int Num> >>> > bool greater(unsigned Val) { >>> > return Val >= 0; >>> > } >>> > >>> > ... greater<0>(42); ... >>> > ... greater<1>(42); ... >>> > ... greater<2>(42); ... >>> > >>> > There would be four warnings on the return line. Ignoring the three >>> > warnings in the specializations and only showing the one from the >>> template >>> > pattern would be best on cutting down the noise. >>> >>> Only for -Wtautological-compare, though, right? >>> >>> I imagine that there are plenty of warnings that would be useful to >>> produce during template instantiation, but impossible to detect by >>> just looking at the pattern (without checking dependent >>> types/expressions). A trivial example would be >>> -Wuninitialized for this code: >>> >>> template<typename T> T newval() { T t; return t; } >>> >>> Here, newval<int>() has undefined behavior, but newval<std::string>() >>> is perfectly correct. >>> >>> So whereas -Wtautological-compare empirically gives almost 100% false >>> positives on dependent expressions, -Wuninitialized probably gives >>> 100% *true* positives. >> >> >> Certainly. There are many warnings in each of these buckets, but >> generally a given warning falls into only one - either it should be done on >> instantiations or patterns. (there are some similar issues with macros and >> other things (sizeof/decltype of implementation-provided types, etc)) >> > >
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