tests: Run tests using edition 2024

[caspermeijn]

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[caspermeijn]

@tabokie Do you understand why tests are not failing for the reason in #1248?

[tabokie]

I believe warnings from code generated by (external) proc-macros will be suppressed (-> rust-lang/rust#53975 (comment)). In our case the macro is manually expanded.

So that specific warning will only appear if you change the origin crate to edition 2024 (and maybe add a dummy struct to expand that macro locally).

[caspermeijn]

I believe warnings from code generated by (external) proc-macros will be suppressed (-> rust-lang/rust#53975 (comment)). In our case the macro is manually expanded.

So that specific warning will only appear if you change the origin crate to edition 2024 (and maybe add a dummy struct to expand that macro locally).

I see. prost-build generates files on disk that is directly includes, so warning in that will trigger in the tests. prost-derive generates the code in memory and there warnings are ignored.

Can we enable those warnings somehow? I would like our test suite to find the problems such as #1248

[tabokie]

I tested you can get some errors by setting both proc-macro crate and test crate to edition-2024. (Maybe a similar prost-derive-2024 that includes ../prost-derive/?)

I haven't looked closely to understand the mechanics, because this clearly contradicts https://github.com/rust-lang/rust/blob/dea1661cdb6ccaa636abdeea3bd0a9804d3db240/compiler/rustc_middle/src/lint.rs#L336-L338 (edition error should be ignored). But based on that snippet I think you can only get the "hard" compatibility errors in this way. Mild clippy warnings are still silenced.

[caspermeijn]

I tested you can get some errors by setting both proc-macro crate and test crate to edition-2024. (Maybe a similar prost-derive-2024 that includes ../prost-derive/?)

Good idea. When I set the edition of the whole workspace, the 2024 lints are applied. See #1256