`x.py check` should check tests by default

[kornelski]

It's possible to have errors in files such as: library/std/src/collections/hash/map/tests.rs and library/alloc/tests/lib.rs, and have ./x.py check pass.

I would expect x.py check to be equivalent of cargo check --all and check every file that CI checks. Otherwise, I run x.py check, push code to a PR, and only find later that I have a typo or such.

[Mark-Simulacrum]

We don't check tests by default, but you can pass --all-targets (x.py check --all-targets) to check tests. I believe this is consistent with cargo check behavior?

One reason we don't check tests by default is that causes duplicate error messages for the 'base' crate typically which are annoying (and most changes don't actually need them). If Cargo handled that and didn't show duplicate messages, I imagine we could change the default as well.

[kornelski]

Oh, you're right. So my mistake was assuming that cargo check is more thorough than it is (my text editor invokes it for me, even for tests, so I didn't realize the command doesn't do everything itself).

[ehuss]

If Cargo handled that and didn't show duplicate messages

Just FYI, 1.55 now deduplicates messages.

[Mark-Simulacrum]

Oh, great news @ehuss -- in that case I'm going to go ahead and reopen this as it seems likely to make sense to check tests (by default, and likely without an option to disable that). Should be a pretty simple adjustment to bootstrap.