Nick Treleaven

Although this solves the `ref` problem, there is another syntax ambiguity with `scope` if we want to extend dip1000. See: https://forum.dlang.org/post/[email protected] I don't think this helps with the `scope` problem.

This makes `_dupCtfe` get inferred `@system` even though there's no cast: ```d foreach (ref e; a) res ~= e; // offending line ``` Not sure how to avoid that. It...

I'm not sure where the cast expression comes from when calling `_dupCtfe`: ```d foreach (ref e; a) res ~= e; // offending line ``` I tried to work around that...

Closing in favour of https://github.com/dlang/dmd/pull/16315#issuecomment-2016931657

I don't understand why this triggers another error in phobos: ``` std/traits.d(5665): Error: function `@safe void std.traits.__unittest_L5602_C7.DerivF.test2()` does not override any function, did you mean to override `@trusted void std.traits.__unittest_L5602_C7.BaseF.test2()`?...

@Bolpat This deprecates casting any class instance to an extern(C++) class type. If the source expression is not a class it still works. *Edit:* unless the target type is a...

I haven't worked on finishing this as it seems quite disruptive given the NG thread about deprecating code that is working properly (even if it catches some code that isn't...

> I think this PR is fine, since there's a good reason and a clear migration path. Given that people are using these casts expecting them to work as C++...

@Geod24 This helps detect *valid* options that don't have `--help` documentation.

You can see the check firing in the tests for the first commit (before I added missing docs) here: https://app.circleci.com/pipelines/github/dlang/dmd/23098/workflows/1da53291-0849-49a4-b6c1-6bc0f758fa21/jobs/50668 ``` core.exception.AssertError@src/dmd/mars.d(1596): missing doc for -multiobj in cli.d ```