Debug assertions are turned off in alloctests

[maxdexh]

The alloc collections make generous use of debug_assert to check their invariants in debug mode. But they don't get run in alloctests!

This led to confusion in #162462 (comment).

Steps to reproduce:

• Add debug_assert!(false); to the body of VecDeque::new
• ./x test alloctests runs without failures

[bjorn3]

Enabling debug assertions for the standard library tests would require recompiling the standard library with debug assertions enabled too as standard library tests must run with the exact same cargo configuration as the sysroot standard library was compiled with to prevent libcore getting duplicated (once from the sysroot through libtest and once as regular dependency of the crate that is being tested) and duplicate lang item errors getting emitted.

[maxdexh]

Hmm, that's unfortunate. I still think the current state isn't ideal. Do the assertions at least run in CI, or are they actually just fancy code comments?

[bjorn3]

Maybe the -alt builders enable them for the standard library? At least for the compiler the -alt builders should enable debug assertions.

[Kobzol]

We should be running all tests on test runners on CI with debug assertions enabled.

[maxdexh]

By "we should", do you mean "I think we do this" or "we should do this"?

[Kobzol]

Sorry for not being clear :)

rust/src/ci/run.sh

Line 151 in 93a81b4

RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-debug-assertions"

we are doing this.

[maxdexh]

Good enough for me. Might lead to more confusion, but at least we don't have broken assertions anywhere :D