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This is similar to C++'s consteval >> keyword. >> >> Convert device_id.rs as an example. >> >> Signed-off-by: Gary Guo >> --- >> rust/build_error.rs | 7 +++++++ >> rust/kernel/const_eval.rs | 9 +++++++++ >> rust/kernel/device_id.rs | 4 ++++ >> rust/kernel/lib.rs | 1 + >> rust/macros/const_eval.rs | 24 ++++++++++++++++++++++++ >> rust/macros/lib.rs | 21 +++++++++++++++++++++ >> 6 files changed, 66 insertions(+) >> >> diff --git a/rust/build_error.rs b/rust/build_error.rs >> index fa24eeef9929..b7ef80596f1f 100644 >> --- a/rust/build_error.rs >> +++ b/rust/build_error.rs >> @@ -29,3 +29,10 @@ >> pub const fn build_error(msg: &'static str) -> ! { >> panic!("{}", msg); >> } >> + >> +/// Assert that the code is in const evaluation. >> +/// >> +/// Triggers a build error if called at runtime. >> +#[inline(never)] >> +#[export_name =3D "rust_const_eval_called_at_runtime"] >> +pub const fn assert_in_const_eval() {} > > IIUC if RUST_BUILD_ASSERT_ALLOW=3Dy then this will not cause a build erro= r > anything built-in. I don't expect the call will ever fail to be > eliminated by link time here, so isn't it better to not use the same > mechanism affected by RUST_BUILD_ASSERT_ALLOW=3Dy here? Guess you would > need to make a new file for this. I could do that, but I also think it's not a big deal to also allow for RUST_BUILD_ASSERT_ALLOW=3Dy builds just to simplify the build system. As long as we have people building code with RUST_BUILD_ASSERT_ALLOW=3Dn th= en the problematic use will be caught. Best, Gary