Remake of "List matching impls on type aliases"
* 4b1d13d
* 6f552c8
* 2ce7cd9

Partially reverts "Fix infinite loop when retrieving impls for
type alias", but keeps the test case.

This version of the PR avoids the infinite loop by structurally
matching types instead of using full unification. This version
does not support type alias trait bounds, but the compiler does
not enforce those anyway
(rust-lang#21903).

Co-authored-by: León Orell Valerian Liehr <me@fmease.dev>

modify fuction clond() -> cloned()

optimize the code

Handle the problem that the pathset is empty and modify the judgment of the builder::tests::test_exclude_kind

Delete unnecessary judegment conditions

skip test for library/std duo to OOM in benches as library/alloc

Add FIXME for WASM32

…-docs, r=oli-obk

Clarify stability guarantee for lifetimes in enum discriminants

Since `std::mem::Discriminant` erases lifetimes, it should be clarified that changing the concrete value of a lifetime parameter does not change the value of an enum discriminant for a given variant. This is useful as it guarantees that it is safe to transmute `Discriminant<Foo<'a>>` to `Discriminant<Foo<'b>>` for any combination of `'a` and `'b`. This also holds for type-generics as long as the type parameters do not change, e.g. `Discriminant<Foo<T, 'a>>` can be transmuted to `Discriminant<Foo<T, 'b>>`.

Side note: Is what I've written actually enough to imply soundness (or rather codify it), or should it specifically be spelled out that it's OK to transmute in the above way?

…an68

Fix Step Skipping Caused by Using the `--exclude` Option

The original code was overreacting to the `--exclude` option,
https://github.com/rust-lang/rust/blob/eadf69a6c6edfe220fc5b1b659e46e271d75a3a1/src/bootstrap/builder.rs#L257-L260
For example:
When `x test --exclude alloc` or `x test --exclude library/alloc` is passed, the entire libraray test is skipped.

Related issues:
rust-lang#112009

…l-list, r=GuillaumeGomez

rustdoc: list matching impls on type aliases

Fixes rust-lang#32077

Fixes rust-lang#99952

Remake of rust-lang#112429

Partially reverts rust-lang#112543, but keeps the test case.

This version of the PR avoids the infinite loop by structurally matching types instead of using full unification. This version does not support type alias trait bounds, but the compiler does not enforce those anyway (rust-lang#21903).

r? `@GuillaumeGomez`

CC `@lcnr`

…t-node, r=petrochenkov

Lint node for `PRIVATE_BOUNDS`/`PRIVATE_INTERFACES` is the item which names the private type

The HIR that the `PRIVATE_BOUNDS` lint should be attached to is the item that has the *bounds*, not the private type. This PR also aligns this behavior with the `EXPORTED_PRIVATE_DEPENDENCIES` lint, which also requires putting the `allow` on the item that names the private type.

Fixes rust-lang#115475

r? petrochenkov

`-Cllvm-args` usability improvement

fixes: rust-lang#26338
fixes: rust-lang#115564

Two problems were found during playing with `-Cllvm-args`

1. When `llvm.link-shared` is set to `false` in `config.toml`, output of `rustc -C llvm-args='--help-list-hidden'` doesn't contain `--emit-dwarf-unwind` and `--emulated-tls`. When it is set to `true`, `rustc -C llvm-args='--help-list-hidden'` emits `--emit-dwarf-unwind`, but `--emulated-tls` is still missing.
2. Setting `-Cllvm-args=--emit-dwarf-unwind=always` doesn't take any effect, but `-Cllvm-args=-machine-outliner-reruns=3` does work.

### 1

Adding `RegisterCodeGenFlags` to register codegen flags fixed the first problem. `rustc -C llvm-args='--help-list-hidden'` emits full codegen flags including `--emit-dwarf-unwind` and `--emulated-tls`.

### 2

Constructing `TargetOptions` from `InitTargetOptionsFromCodeGenFlags` in `LLVMRustCreateTargetMachine` fixed the second problem. The `LLVMRustSetLLVMOptions` calls `ParseCommandLineOptions` which parses given `llvm-args`. For options like `machine-outliner-reruns`, it just works, since the codegen logic directly consumes the parsing result:

[machine-outliner-reruns register](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/lib/CodeGen/MachineOutliner.cpp#L114)
[machine-outliner-reruns consumption](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/lib/CodeGen/MachineOutliner.cpp#L1138)

But for flags defined in `TargetOptions` and `MCTargetOptions` to take effect, constructing them with `InitTargetOptionsFromCodeGenFlags` is essential, or the parsing result is just not consumed. Similar patterns can be observed in [lli](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/tools/llc/llc.cpp#L494), [llc](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/tools/lli/lli.cpp#L517), etc.

…-obk

fix: return early when has tainted in mir-lint

Fixes rust-lang#115203

`a[..]` is of indeterminate size, it had been reported error during borrow check, therefore we skip the mir lint process.