JonasToth 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]
+ }
----------------
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).
Repository:
rCTE Clang Tools Extra
https://reviews.llvm.org/D53488
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