[PATCH] D126907: Deferred Concept Instantiation Implementation Take 2

[Erich Keane via Phabricator via cfe-commits]

erichkeane added a comment.

In D126907#3849583 <https://reviews.llvm.org/D126907#3849583>, @erichkeane wrote:

> In D126907#3846591 <https://reviews.llvm.org/D126907#3846591>, @erichkeane wrote:
>
>> In D126907#3844788 <https://reviews.llvm.org/D126907#3844788>, @BertalanD wrote:
>>
>>> Hi @erichkeane,
>>>
>>> This change broke compilation of this program (https://godbolt.org/z/KrWGvcf8h; reduced from https://github.com/SerenityOS/ladybird):
>>>
>>>   template<typename T, typename U>
>>>   constexpr bool IsSame = false;
>>>   
>>>   template<typename T>
>>>   constexpr bool IsSame<T, T> = true;
>>>   
>>>   template<typename T>
>>>   struct Foo {
>>>       template<typename U>
>>>       Foo(U&&) requires (!IsSame<U, Foo>);
>>>   };
>>>   
>>>   template<>
>>>   struct Foo<void> : Foo<int> {
>>>       using Foo<int>::Foo;
>>>   };
>>>   
>>>   Foo<void> test() { return 0; }
>>>
>>>
>>>
>>>   <source>:18:27: error: invalid reference to function 'Foo': constraints not satisfied
>>>   Foo<void> test() { return 0; }
>>>                             ^
>>>   <source>:10:24: note: because substituted constraint expression is ill-formed: value of type '<dependent type>' is not contextually convertible to 'bool'
>>>       Foo(U&&) requires (!IsSame<U, Foo>);
>>>                          ^
>>
>> Thanks for the report!  I'll look into it ASAP.
>
> Quick note: I believe I understand the cause of this, which requires a bit more work than I otherwise would have expected.  I have a candidate patch I'm running through my testing right now that should fix this, but it still needs cleaning up.  Expect it in the next day or two if all goes well.



In D126907#3850735 <https://reviews.llvm.org/D126907#3850735>, @BertalanD wrote:

> In D126907#3849583 <https://reviews.llvm.org/D126907#3849583>, @erichkeane wrote:
>
>> In D126907#3846591 <https://reviews.llvm.org/D126907#3846591>, @erichkeane wrote:
>>
>>> In D126907#3844788 <https://reviews.llvm.org/D126907#3844788>, @BertalanD wrote:
>>>
>>>> Hi @erichkeane,
>>>>
>>>> This change broke compilation of this program (https://godbolt.org/z/KrWGvcf8h; reduced from https://github.com/SerenityOS/ladybird):
>>>>
>>>>   template<typename T, typename U>
>>>>   constexpr bool IsSame = false;
>>>>   
>>>>   template<typename T>
>>>>   constexpr bool IsSame<T, T> = true;
>>>>   
>>>>   template<typename T>
>>>>   struct Foo {
>>>>       template<typename U>
>>>>       Foo(U&&) requires (!IsSame<U, Foo>);
>>>>   };
>>>>   
>>>>   template<>
>>>>   struct Foo<void> : Foo<int> {
>>>>       using Foo<int>::Foo;
>>>>   };
>>>>   
>>>>   Foo<void> test() { return 0; }
>>>>
>>>>
>>>>
>>>>   <source>:18:27: error: invalid reference to function 'Foo': constraints not satisfied
>>>>   Foo<void> test() { return 0; }
>>>>                             ^
>>>>   <source>:10:24: note: because substituted constraint expression is ill-formed: value of type '<dependent type>' is not contextually convertible to 'bool'
>>>>       Foo(U&&) requires (!IsSame<U, Foo>);
>>>>                          ^
>>>
>>> Thanks for the report!  I'll look into it ASAP.
>>
>> Quick note: I believe I understand the cause of this, which requires a bit more work than I otherwise would have expected.  I have a candidate patch I'm running through my testing right now that should fix this, but it still needs cleaning up.  Expect it in the next day or two if all goes well.
>
> Thank you for your quick response and for creating this massive yak shave of a patch :D
>
> Please ping me if you want me to test the fix on our code, or if I can help in some other way.

Thanks for the offer!  I ended up taking a less-aggressive yak shave on this one, and have a patch here: https://reviews.llvm.org/D135772

If you could give it a try, it would be very useful!


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  https://reviews.llvm.org/D126907/new/

https://reviews.llvm.org/D126907