Add a note about overflowing in the `RangeFrom` iterator

Replace consider_unification_despite_ambiguity with new obligation variant

Is work towards #32730. Addresses part one of #32286. Addresses #24210 and #26046 to some degree.

r? @nikomatsakis

Do not rely on file extensions after path canonicalization.

Rustc does not recognize libraries which are symlinked to files having extension other than .rlib. The problem is that find_library_crate calls fs::canonicalize on found library paths, but then the resulting path is passed to get_metadata_section, which assumes it will end in ".rlib" if it's an rlib (from https://internals.rust-lang.org/t/is-library-path-canonicalization-worth-it/3206).

cc #29433

Warn for type parameter defaults on impl blocks

Warn for type parameter defaults on impl blocks (fixes #31543).
r? @nikomatsakis

Fix stack overflow detection on FreeBSD

resolve: Improve duplicate glob detection

This fixes a bug introduced in #31726 in which we erroneously allow multiple imports of the same item under some circumstances.

More specifically, we erroneously allow a module that is in a cycle of glob re-exports to have other re-exports (besides the glob from the cycle).
For example,
```rust
pub fn f() {}
mod foo {
    pub use f; // (1) This defines `foo::f`.
    pub use bar::*; // (3) This also defines `foo::f`, which should be a duplicate error but is currently allowed.
}
mod bar {
    pub use foo::*; // (2) This defines `bar::f`.
}
```

A module in a glob re-export cycle can still have `pub` items after this PR. For example,
```rust
mod foo {
    pub fn f() {}; // (1) This defines `foo::f`.
    pub use bar::*; // (3) This is not a duplicate error since items shadow glob-imported re-exports (cf #31337).
}
mod bar {
    pub use foo::*; // (2) This defines `bar::f`.
}
```
r? @nikomatsakis

Initial implementation of debuginfo in MIR trans.

Progress is made towards #31005, but several issues remain, such as #32790.

rustbuild: Migrate tidy checks to Rust

This commit rewrites all of the tidy checks we have, namely:

* featureck
* errorck
* tidy
* binaries

into Rust under a new `tidy` tool inside of the `src/tools` directory. This at
the same time deletes all the corresponding Python tidy checks so we can be sure
to only have one source of truth for all the tidy checks.

cc #31590

This verifies that the crates listed in the `[dependencies]` section of
`Cargo.toml` are a subset of the crates listed in `lib.rs` for our in-tree
crates. This should help ensure that when we refactor crates over time we keep
these dependency lists in sync.

Describe more platform-specific behaviors of `std::fs::rename`

I did some tests myself regarding the situation when both `from` and `to` exist, and the results were:

On Linux:

`from` | `to` | Result
---- | ---- | ----
Directory | Directory | Ok
Directory | File | Error
File | Directory | Error
File | File | Ok

On Windows:

`from` | `to` | Result
---- | ---- | ----
Directory | Directory | Error
Directory | File | Ok
File | Directory | Error
File | File | Ok

This is a bit against the official MSDN documentation, which says "(`MOVEFILE_REPLACE_EXISTING`) cannot be used if `lpNewFileName` or `lpExistingFileName` names a directory." As evidenced above, `lpExistingFileName` *can* be a directory.

I also mentioned the atomicity of the operation.

Fixes #31301.

This commit rewrites all of the tidy checks we have, namely:

* featureck
* errorck
* tidy
* binaries

into Rust under a new `tidy` tool inside of the `src/tools` directory. This at
the same time deletes all the corresponding Python tidy checks so we can be sure
to only have one source of truth for all the tidy checks.

cc #31590

rustdoc: Fix testing no_run code blocks

This was a regression introduced by #31250 where the compiler deferred returning
the results of compilation a little too late (after the `Stop` check was looked
at). This commit alters the stop point to first try to return an erroneous
`result` and only if it was successful return the sentinel `Err(0)`.

Closes #31576

std: Stabilize APIs for the 1.9 release

This commit applies all stabilizations, renamings, and deprecations that the
library team has decided on for the upcoming 1.9 release. All tracking issues
have gone through a cycle-long "final comment period" and the specific APIs
stabilized/deprecated are:

Stable

* `std::panic`
* `std::panic::catch_unwind` (renamed from `recover`)
* `std::panic::resume_unwind` (renamed from `propagate`)
* `std::panic::AssertUnwindSafe` (renamed from `AssertRecoverSafe`)
* `std::panic::UnwindSafe` (renamed from `RecoverSafe`)
* `str::is_char_boundary`
* `<*const T>::as_ref`
* `<*mut T>::as_ref`
* `<*mut T>::as_mut`
* `AsciiExt::make_ascii_uppercase`
* `AsciiExt::make_ascii_lowercase`
* `char::decode_utf16`
* `char::DecodeUtf16`
* `char::DecodeUtf16Error`
* `char::DecodeUtf16Error::unpaired_surrogate`
* `BTreeSet::take`
* `BTreeSet::replace`
* `BTreeSet::get`
* `HashSet::take`
* `HashSet::replace`
* `HashSet::get`
* `OsString::with_capacity`
* `OsString::clear`
* `OsString::capacity`
* `OsString::reserve`
* `OsString::reserve_exact`
* `OsStr::is_empty`
* `OsStr::len`
* `std::os::unix::thread`
* `RawPthread`
* `JoinHandleExt`
* `JoinHandleExt::as_pthread_t`
* `JoinHandleExt::into_pthread_t`
* `HashSet::hasher`
* `HashMap::hasher`
* `CommandExt::exec`
* `File::try_clone`
* `SocketAddr::set_ip`
* `SocketAddr::set_port`
* `SocketAddrV4::set_ip`
* `SocketAddrV4::set_port`
* `SocketAddrV6::set_ip`
* `SocketAddrV6::set_port`
* `SocketAddrV6::set_flowinfo`
* `SocketAddrV6::set_scope_id`
* `<[T]>::copy_from_slice`
* `ptr::read_volatile`
* `ptr::write_volatile`
* The `#[deprecated]` attribute
* `OpenOptions::create_new`

Deprecated

* `std::raw::Slice` - use raw parts of `slice` module instead
* `std::raw::Repr` - use raw parts of `slice` module instead
* `str::char_range_at` - use slicing plus `chars()` plus `len_utf8`
* `str::char_range_at_reverse` - use slicing plus `chars().rev()` plus `len_utf8`
* `str::char_at` - use slicing plus `chars()`
* `str::char_at_reverse` - use slicing plus `chars().rev()`
* `str::slice_shift_char` - use `chars()` plus `Chars::as_str`
* `CommandExt::session_leader` - use `before_exec` instead.

Closes #27719
cc #27751 (deprecating the `Slice` bits)
Closes #27754
Closes #27780
Closes #27809
Closes #27811
Closes #27830
Closes #28050
Closes #29453
Closes #29791
Closes #29935
Closes #30014
Closes #30752
Closes #31262
cc #31398 (still need to deal with `before_exec`)
Closes #31405
Closes #31572
Closes #31755
Closes #31756

Fixes #31301.

Fix the span for try shorthand expressions

My five character contribution to the rust parser! Fixes https://github.com/rust-lang/rust/issues/32709.

Rollup of 9 pull requests

- Successful merges: #32768, #32802, #32815, #32823, #32849, #32854, #32862, #32870, #32873
- Failed merges:

This was a regression introduced by #31250 where the compiler deferred returning
the results of compilation a little too late (after the `Stop` check was looked
at). This commit alters the stop point to first try to return an erroneous
`result` and only if it was successful return the sentinel `Err(0)`.

Closes #31576

This commit applies all stabilizations, renamings, and deprecations that the
library team has decided on for the upcoming 1.9 release. All tracking issues
have gone through a cycle-long "final comment period" and the specific APIs
stabilized/deprecated are:

Stable

* `std::panic`
* `std::panic::catch_unwind` (renamed from `recover`)
* `std::panic::resume_unwind` (renamed from `propagate`)
* `std::panic::AssertUnwindSafe` (renamed from `AssertRecoverSafe`)
* `std::panic::UnwindSafe` (renamed from `RecoverSafe`)
* `str::is_char_boundary`
* `<*const T>::as_ref`
* `<*mut T>::as_ref`
* `<*mut T>::as_mut`
* `AsciiExt::make_ascii_uppercase`
* `AsciiExt::make_ascii_lowercase`
* `char::decode_utf16`
* `char::DecodeUtf16`
* `char::DecodeUtf16Error`
* `char::DecodeUtf16Error::unpaired_surrogate`
* `BTreeSet::take`
* `BTreeSet::replace`
* `BTreeSet::get`
* `HashSet::take`
* `HashSet::replace`
* `HashSet::get`
* `OsString::with_capacity`
* `OsString::clear`
* `OsString::capacity`
* `OsString::reserve`
* `OsString::reserve_exact`
* `OsStr::is_empty`
* `OsStr::len`
* `std::os::unix::thread`
* `RawPthread`
* `JoinHandleExt`
* `JoinHandleExt::as_pthread_t`
* `JoinHandleExt::into_pthread_t`
* `HashSet::hasher`
* `HashMap::hasher`
* `CommandExt::exec`
* `File::try_clone`
* `SocketAddr::set_ip`
* `SocketAddr::set_port`
* `SocketAddrV4::set_ip`
* `SocketAddrV4::set_port`
* `SocketAddrV6::set_ip`
* `SocketAddrV6::set_port`
* `SocketAddrV6::set_flowinfo`
* `SocketAddrV6::set_scope_id`
* `<[T]>::copy_from_slice`
* `ptr::read_volatile`
* `ptr::write_volatile`
* The `#[deprecated]` attribute
* `OpenOptions::create_new`

Deprecated

* `std::raw::Slice` - use raw parts of `slice` module instead
* `std::raw::Repr` - use raw parts of `slice` module instead
* `str::char_range_at` - use slicing plus `chars()` plus `len_utf8`
* `str::char_range_at_reverse` - use slicing plus `chars().rev()` plus `len_utf8`
* `str::char_at` - use slicing plus `chars()`
* `str::char_at_reverse` - use slicing plus `chars().rev()`
* `str::slice_shift_char` - use `chars()` plus `Chars::as_str`
* `CommandExt::session_leader` - use `before_exec` instead.

Closes #27719
cc #27751 (deprecating the `Slice` bits)
Closes #27754
Closes #27780
Closes #27809
Closes #27811
Closes #27830
Closes #28050
Closes #29453
Closes #29791
Closes #29935
Closes #30014
Closes #30752
Closes #31262
cc #31398 (still need to deal with `before_exec`)
Closes #31405
Closes #31572
Closes #31755
Closes #31756

Match signed/unsigned integer type docs

* Copy documentation from signed implementation to unsigned implementation, where necessary.

A few functions had elaborate docs in the signed version but not in the unsigned version. This probably happenned because the signed version is at the top and the author didn't realize they had to update the documentation in both locations.

* Use signed integers in signed documentation, where possible.

r? @steveklabnik

Fix Windows UNC paths in std::path docs

Bit-magic for faster is_char_boundary

The asm generated for b < 128 || b >= 192 is not ideal, as it computes
both sub-inequalities. This patch replaces it with bit magic.

Fixes #32471

Add some missing commas and missing titles/formatting

Fixes #29373.

r? @steveklabnik

resolve: import resolution diagnostics

This improves the diagnostics for failing import resolutions (fixes #32833).
r? @EddyB