Don't copy symbols from dylibs with `-Zdylib-lto`
When `rustc_driver` started being built with `-Zdylib-lto -Clto=thin`, some libstd symbols were copied by the LTO process into the dylib. That causes duplicate local symbols that are not present otherwise.
Depending on the situation (lib loading order apparently), the duplicated symbols could cause issues: `rustc_driver` overrode the panic hook, but it didn't apply to rustc main's hook (the default from libstd). This is the cause of #105637, in some situations the panic hook installed by `rustc_driver` isn't executed, and only libstd's backtrace is shown (and a double panic). The query stack, as well as the various notes to open a GH about the ICE, don't appear.
It's not clear exactly what is needed to trigger the issue, but I have simulated a reproducer [here](https://github.com/lqd/issue-105637) with cargo involved, the incorrect panic hook is executed on my machine. It is hard to reproduce in a unit test: `cargo run` + `rustup` involves LD_LIBRARY_PATH, which is not the case for `compiletest`. cargo also adds unconditional flags that are then overridden in [`bootstrap` when building rustc with `rust.lto = thin`](9c07efe84f/src/bootstrap/compile.rs (L702-L714)) as done on CI).
All this to say the compilation and execution environment in `bootstrap` leading to the bug building `rustc_driver` is different from our UI tests, and I believe one of the reasons it's hard to make an exact reproducer test. Thankfully there's _still_ a difference in the behavior though: although in the unit test the correct panic hook seems to be executed compared to my repro and the current nightly, only the fix removes the double panic here.
The `7e8277aefa12f1469fb1df01418ff5846a7854a9` `try` build:
- fixes the reproducer repo linked above
- restores the ICE messages from https://github.com/rust-lang/rust/issues/105321 back to the state in its OP compared to the description in https://github.com/rust-lang/rust/issues/105637
- restores the ICE message and the query stack from https://github.com/rust-lang/rust/issues/105777 compared to nightly
While I believe this technically fixes the P-critical issue https://github.com/rust-lang/rust/issues/105637, I would not want to close it yet as we may want to backport to beta/stable (if a point release happens, it would fix the ICEs reported on 1.66.0, which is built with ThinLTO on linux). Once this PR lands, I'll also open another PR to re-enable ThinLTO on x64 darwin's dist builder.
Rollup of 6 pull requests
Successful merges:
- #105493 (Help rust-analyzer normalize query return types)
- #105710 (Don't bug if we're trying to cast `dyn*` to another type)
- #105711 (bail in `collect_trait_impl_trait_tys` if signatures reference errors)
- #105768 (Detect inherent associated types not having CamelCase)
- #105780 (rustdoc: Don't add "Read more" link if there is no extra content)
- #105802 (Make enum-match.rs test robust against variable name changes)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Stabilize default_alloc_error_handler
Tracking issue: #66741
This turns `feature(default_alloc_error_handler)` on by default, which causes the compiler to automatically generate a default OOM handler which panics if `#[alloc_error_handler]` is not provided.
The FCP completed over 2 years ago but the stabilization was blocked due to an issue with unwinding. This was fixed by #88098 so stabilization can be unblocked.
Closes#66741
Rewrite `E0158` error-code docs for clarity
Fixes#105585.
The `E0158` error-code docs are unclear. It doesn't explain all three different variants of the error and doesn't explain *why* the error occurs. This PR cleans it up a bit and brings it properly into line with [RFC1567](https://rust-lang.github.io/rfcs/1567-long-error-codes-explanation-normalization.html).
I'm a first time Rust contributor so I've probably not got it quite right. I also haven't run the whole build process because I assume that my minor docs changes shouldn't break everything.
always use `anonymize_bound_vars`
Unless this is perf-sensitive, it's probably best to always use one anonymize function that does the right thing for all bound vars.
r? types
Move `TypeckResults` to separate module
`ty::context` is really big and the typeck results aren't directly related to `TyCtxt`, so move them to a separate module. Also contains a small drive-by macro "improvement".
Custom MIR: Many more improvements
Commits are each atomic changes, best reviewed one at a time, with the exception that the last commit includes all the documentation.
### First commit
Unsafetyck was not correctly disabled before for `dialect = "built"` custom MIR. This is fixed and a regression test is added.
### Second commit
Implements `Discriminant`, `SetDiscriminant`, and `SwitchInt`.
### Third commit
Implements indexing, field, and variant projections.
### Fourth commit
Documents the previous commits and everything else.
There is some amount of weirdness here due to having to beat Rust syntax into cooperating with MIR concepts, but it hopefully should not be too much. All of it is documented.
r? `@oli-obk`
