[PATCH] D156244: [clang] Do not crash on use of a variadic overloaded operator

[Mariya Podchishchaeva via Phabricator via cfe-commits]

Fznamznon added inline comments.


================
Comment at: clang/test/SemaCXX/overloaded-operator-decl.cpp:64
+class E {};
+void operator+(E, ...) {} // expected-error{{overloaded 'operator+' cannot be variadic}}
+void d() { E() + E(); }
----------------
aaron.ballman wrote:
> I think it might make sense to extend the test coverage for the other operators you can overload, just to demonstrate we diagnose them all consistently. WDYT?
Okay, while trying to add more test cases I discovered that following
```
class E {};
bool operator<(const E& lhs, ...);
auto operator<=>(const E& lhs, ...);

void d() {
  E() < E();
}
```
crashes even with the patch since there is code searching for best overload candidate that doesn't consider possibility for them making variadic.
The code around overloading is actually pretty inconsistent, somewhere invalid candidates are considered, and somewhere not, so I spent some time not knowing what to do.
I'm now inclined that we just shouldn't consider invalid candidates like @shafik 
suggests. WDYY?



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  https://reviews.llvm.org/D156244/new/

https://reviews.llvm.org/D156244