gchatelet marked 8 inline comments as done.
gchatelet added inline comments.
================
Comment at: test/clang-tidy/cppcoreguidelines-narrowing-conversions.cpp:164
+ while (i) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: narrowing conversion from
'int' to 'bool' [cppcoreguidelines-narrowing-conversions]
+ }
----------------
JonasToth wrote:
> lebedev.ri wrote:
> > courbet wrote:
> > > What about providing a fix for this one :
> > > `while (i != 0) {`
> > Is this //actually// a narrowing conversion as per the CPPCG?
> > Conversion to bool is a special case, it's not a truncation, but a `x != 0`.
> > I'd think cases like these where bool was pretty clearly meant (`if()`,
> > `while()`, `for()`, ???) should be exempt.
> No it is not an narrowing conversion the CPPCG are concerned:
> https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#es46-avoid-lossy-narrowing-truncating-arithmetic-conversions
>
> Short:
> ```
> ES.46: Avoid lossy (narrowing, truncating) arithmetic conversions
>
> Enforcement
>
> A good analyzer can detect all narrowing conversions. However, flagging all
> narrowing conversions will lead to a lot of false positives. Suggestions:
>
> - flag all floating-point to integer conversions (maybe only float->char
> and double->int. Here be dragons! we need data)
> - flag all long->char (I suspect int->char is very common. Here be
> dragons! we need data)
> - consider narrowing conversions for function arguments especially suspect
> ```
>
> We do have a readability-check that is concerned about int -> bool
> conversions. Because of that I think we could safely ignore the `int->bool`
> conversion.
> But `float -> bool` is still suspicious in my opinion. It has the same
> semantics, but comparing `float` on equality is dangerous and one could argue
> it shall be enforced through point 1 (all float-to-int conversions).
@JonasToth Do you have the name of the readability check so I can document the
behavior?
Repository:
rCTE Clang Tools Extra
https://reviews.llvm.org/D53488
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
