[PATCH] D106302: Implement P1937 consteval in unevaluated contexts

[Corentin Jabot via Phabricator via cfe-commits]

cor3ntin added inline comments.


================
Comment at: clang/test/SemaCXX/cxx2a-consteval.cpp:612
+static_assert(is_same<long, T>::value);
+
+} // namespace unevaluated
----------------
aaron.ballman wrote:
> Here's an interesting test case:
> ```
> #include <typeinfo>
> 
> struct S {
>   virtual void f();
> };
> 
> struct D : S {
>   void f() override;
> };
> 
> consteval S *get_s() { return nullptr; }
> 
> void func() {
>   (void)typeid(*get_s());
> }
> ```
> `typeid` still needs to evaluate its operand (due to the polymorphic return type of `*get_s()`), and so you should get a diagnostic about evaluating the side effects by calling `get_s()`. I think this then runs into https://eel.is/c++draft/expr.const#13.sentence-3 and we should diagnose?
Not sure!
Also, in the context of this pr, the question is also whether `decltype(typeid(*get_s()))` should be ill-formed I think


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D106302/new/

https://reviews.llvm.org/D106302