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

[Clement Courbet via Phabricator via cfe-commits]

courbet added inline comments.


================
Comment at: clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp:35
+                                      hasSourceExpression(IsFloatExpr),
+                                      unless(hasParent(castExpr())))
+                         .bind("cast"),
----------------
aaron.ballman wrote:
> courbet wrote:
> > 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.
> I truly meant `(double)0.5` -- where the cast has no impact on the narrowing conversion, but the check still doesn't diagnose because there's an explicit cast present. Should the check be checking for explicit casts to the narrowed type?
OK, then that's fine (I added a test for that for): there is an explicit cast to double, but then the compiler generates an extra cast to int on top, which triggers.


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D38455