[PATCH] D38455: [clang-tidy] new cppcoreguidelines-narrowing-conversions check.

[Clement Courbet via Phabricator via cfe-commits]

courbet added a comment.

Thanks.



================
Comment at: clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp:35
+                                      hasSourceExpression(IsFloatExpr),
+                                      unless(hasParent(castExpr())))
+                         .bind("cast"),
----------------
aaron.ballman wrote:
> I believe this code will not diagnose under this check -- is that intended as a way to silence the check?
> ```
> i += (double)0.5;
> ```
Did you mean `(int)0.5` ?

Yes, the user essentially told us they knew what they were doing. I've added an explicit test for this.


================
Comment at: test/clang-tidy/cppcoreguidelines-narrowing-conversions.cpp:81
+
+}  // namespace floats
----------------
aaron.ballman wrote:
> What should happen in cases like the following:
> ```
> template <typename T1, typename T2>
> void f(T1 one, T2 two) {
>   one += two;
> }
> 
> void g() {
>   f(1, 2);
>   f(1, .5);
> }
> 
> #define DERP(i, j) (i += j)
> 
> void h() {
>   int i = 0;
>   DERP(1, 2);
>   DERP(i, .5);
> }
> ```
I added more tests.


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D38455