[Clang] Explain satisfaction failure for more type traits

[cor3ntin]

Last week, we added the scaffolding for clang to explain why a standard type trait is not satisfied - when used either in a static_assert or as atomic constraint, in Sema::DiagnoseTypeTraitDetails (#141238)

https://gcc.godbolt.org/z/xb7PcxzTx

So far, this has only been done for std::is_trivially_relocatable.

There are plenty of type traits that could benefit from additional diagnostics
https://eel.is/c++draft/type.traits#meta.type.synop

I figure adding support for more type traits (one at a time!) could be a good first issue, and it's always nice to improve our diagnostics.

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor is working on this issue. If someone is assigned to the issue or claimed to be working on it, ping the person. After one week without a response, the assignee may be changed.
2. Leave a comment indicating that you are working on the issue, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: cor3ntin (cor3ntin)

Last week, we added the scaffolding for clang to explain _why_ a standard type trait is not satisfied - when used either in a `static_assert` or as atomic constraint, in `Sema::DiagnoseTypeTraitDetails` (#141238)

https://gcc.godbolt.org/z/xb7PcxzTx

So far, this has only been done for std::is_trivially_relocatable.

There are plenty of type traits that could benefit from additional diagnostics
https://eel.is/c++draft/type.traits#meta.type.synop

I figure adding support for more type traits (one at a time!) could be a good first issue, and it's always nice to improve our diagnostics.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: cor3ntin (cor3ntin)

Last week, we added the scaffolding for clang to explain _why_ a standard type trait is not satisfied - when used either in a `static_assert` or as atomic constraint, in `Sema::DiagnoseTypeTraitDetails` (#141238)

https://gcc.godbolt.org/z/xb7PcxzTx

So far, this has only been done for std::is_trivially_relocatable.

There are plenty of type traits that could benefit from additional diagnostics
https://eel.is/c++draft/type.traits#meta.type.synop

I figure adding support for more type traits (one at a time!) could be a good first issue, and it's always nice to improve our diagnostics.

[snarang181]

@cor3ntin, do you have a suggestion on a type trait I can pick up and work on adding diagnostics for it?

[egorshamshura]

Hello, I'd like to implement support for some type traits too. Could someone please assign this to me?

[shafik]

@snarang181 @egorshamshura we assign after a PR is created but if you are starting work you should announce it considering that both of you have shown interest and it would be good to avoid duplicating work.

[egorshamshura]

I want to pick up std::is_trivially_copyable

[egorshamshura]

Added a pull request for trivially copyable PR