[clang] [diagnostics] Now the diagnostic message for std headers should mention std module too

[ChuanqiXu9]

Reproducer:

class A {};
auto f() {
    return typeid(A);
}

Now we get:

<source>:3:12: error: you need to include <typeinfo> before using the 'typeid' operator
    3 |     return typeid(A);
      |            ^

but I think we should say "or import std" too. As now both libc++, libstdc++ and MSSTL supports std module and clang is able to compile all of them.

There may be other similar examples.

[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-good-first-issue

Author: Chuanqi Xu (ChuanqiXu9)

Details

Reproducer:

class A {};
auto f() {
    return typeid(A);
}

Now we get:

<source>:3:12: error: you need to include <typeinfo> before using the 'typeid' operator
    3 |     return typeid(A);
      |            ^

but I think we should say "or import std" too. As now both libc++, libstdc++ and MSSTL supports std module and clang is able to compile all of them.

There may be other similar examples.

[llvmbot]

@llvm/issue-subscribers-clang-modules

Author: Chuanqi Xu (ChuanqiXu9)

Details

Reproducer:

class A {};
auto f() {
    return typeid(A);
}

Now we get:

<source>:3:12: error: you need to include <typeinfo> before using the 'typeid' operator
    3 |     return typeid(A);
      |            ^

but I think we should say "or import std" too. As now both libc++, libstdc++ and MSSTL supports std module and clang is able to compile all of them.

There may be other similar examples.

[AltriaSuki]

Hi,may i take on this issue?

[ChuanqiXu9]

Hi,may i take on this issue?

Yeah

[shivam-dhir]

Would love to work on this.

[shafik]

Would love to work on this.

There is already a PR. We don't assign frontend issues until there is a PR and we confirm it looks like a reasonable start.