[PATCH] D53488: [clang-tidy] Catching narrowing from double to float.

[Guillaume Chatelet via Phabricator via cfe-commits]

gchatelet added inline comments.


================
Comment at: clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp:58
+                       const QualType Rhs) {
+  assert(Lhs->isRealType());     // Either integer or floating point.
+  assert(Rhs->isFloatingType()); // Floating point only.
----------------
JonasToth wrote:
> Couldn't be the conversion from an `int` to an `enum` be considered narrowing as well? (Not sure about the word of the standard) I think it makes sense to change the `assert` to `return false`
This is a good point but I'd like to implement this as a second patch if you don't mind.
I created this bug to track it:
https://bugs.llvm.org/show_bug.cgi?id=39401


================
Comment at: clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp:83
+  } else {
+    llvm_unreachable("Invalid state");
   }
----------------
hokein wrote:
> We expect that there are only two possible cases here, how about rearrange the code like below, which I think it would simpler and improve code readability.
> 
> ```
> if (const auto *Op = Nodes.getNodeAs<BinaryOperator>("op")) {
>   // handle case for "op".
>   return;
> }
> const auto *Cast = Nodes.getNodeAs<ImplicitCastExpr>("cast");
> assert(Cast && "must be cast cases");
> // ...
> ```
I see.
However I plan to add two improvement to this clang tidy so the number of cases will increase.
What do you think about the following code?
```
  if (const auto *Op = Nodes.getNodeAs<BinaryOperator>("op"))
    return checkBinaryOperator(*Op);
  if (const auto *Cast = Nodes.getNodeAs<ImplicitCastExpr>("cast"))
    return checkCastOperator(*Cast);
  llvm_unreachable("must be binary operator or cast expression");

```


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D53488