…o actual changes in behaviour

This makes `type_alias_impl_trait` not actually do anything anymore

This change makes it easier to follow the control flow.

I also moved the end-of-line comments attached to some symbols to before
the symbol listing. This allows rustfmt to format the code; otherwise no
formatting occurs (see rust-lang/rustfmt#4750).

E.g., `#[doc(123)]`.

"crate level attribute" -> "crate-level attribute"

It seems there are two copies of it: one in `src/test/ui/attributes/`
and one in `src/test/rustdoc-ui/`. I'm guessing this is to test that the
lint is emitted both when you run the compiler and when you run rustdoc.

Found while investigating rust-lang#82933 - all LocalDefIds are expected to have
HirIds, there's no point in pretending otherwise.

Merges `if-let` and `if x.is_some() { ... }` blocks

- Tweak lint message
- Display multi-segment paths correctly

Fixes rust-lang#83112

The location information for a dummy span isn't real, so don't encode
it. This brings the incr comp cache code into line with the Span
`StableHash` impl, which doesn't hash the location information for dummy
spans.

Previously, we would attempt to load the 'original' file from a dummy
span - if the file id changed (e.g. due to being moved on disk), we would get an
ICE, since the Span was still valid due to its hash being unchanged.

Now that future-incompat-report support has landed in nightly Cargo, we
can start to make progress towards removing the various proc-macro
back-compat hacks that have accumulated in the compiler.

This PR introduces a new lint `proc_macro_back_compat`, which results in
a future-incompat-report entry being generated. All proc-macro
back-compat warnings will be grouped under this lint. Note that this
lint will never actually become a hard error - instead, we will remove
the special cases for various macros, which will cause older versions of
those crates to emit some other error.

I've added code to fire this lint for the `time-macros-impl` case. This
is the easiest case out of all of our current back-compat hacks - the
crate was renamed to `time-macros`, so seeing a filename with
`time-macros-impl` guarantees that an older version of the parent `time`
crate is in use.

When Cargo's future-incompat-report feature gets stabilized, affected
users will start to see future-incompat warnings when they build their
crates.

This detects all Java literal types and all single word C data types,
and suggests the corresponding Rust literal type.

Add a `min_type_alias_impl_trait` feature gate

This new feature gate only permits type alias impl trait to be constrained by function and trait method return types. All other possible constraining sites like const/static types, closure return types and binding types are now forbidden and gated under the `type_alias_impl_trait` and `impl_trait_in_bindings` feature gates (which are both marked as incomplete, as they have various ways to ICE the compiler or cause query cycles where they shouldn't).

r? ``@nikomatsakis``

This is best reviewed commit-by-commit

… r=varkor

Custom error on literal names from other languages

This detects all Java literal types and all single word C data types, and suggests the corresponding Rust literal type.

…ange, r=davidtwco

Validate rustc_layout_scalar_valid_range_{start,end} attributes

Fixes rust-lang#82251, fixes rust-lang#82981.

…dtwco

Find more invalid doc attributes

- Lint on `#[doc(123)]`, `#[doc("hello")]`, etc.
- Lint every attribute; e.g., will now report two warnings for `#[doc(foo, bar)]`
- Add hyphen to "crate level"
- Display paths like `#[doc(foo::bar)]` correctly instead of as an empty string

Remove unused `opt_local_def_id_to_hir_id` function

Found while investigating rust-lang#82933 - all LocalDefIds are expected to have
HirIds, there's no point in pretending otherwise.

Fix typos in `library/core/src/ptr/mod.rs` and `library/std/src/sys_common/thread_local_dtor.rs`

adress -> address

…as-schievink

Minor refactoring in try_index_step

Merges `if-let` and `if x.is_some() { ... }` blocks

…petrochenkov

Introduce `proc_macro_back_compat` lint, and emit for `time-macros-impl`

Now that future-incompat-report support has landed in nightly Cargo, we
can start to make progress towards removing the various proc-macro
back-compat hacks that have accumulated in the compiler.

This PR introduces a new lint `proc_macro_back_compat`, which results in
a future-incompat-report entry being generated. All proc-macro
back-compat warnings will be grouped under this lint. Note that this
lint will never actually become a hard error - instead, we will remove
the special cases for various macros, which will cause older versions of
those crates to emit some other error.

I've added code to fire this lint for the `time-macros-impl` case. This
is the easiest case out of all of our current back-compat hacks - the
crate was renamed to `time-macros`, so seeing a filename with
`time-macros-impl` guarantees that an older version of the parent `time`
crate is in use.

When Cargo's future-incompat-report feature gets stabilized, affected
users will start to see future-incompat warnings when they build their
crates.

…stebank

Don't encode file information for span with a dummy location

Fixes rust-lang#83112

The location information for a dummy span isn't real, so don't encode
it. This brings the incr comp cache code into line with the Span
`StableHash` impl, which doesn't hash the location information for dummy
spans.

Previously, we would attempt to load the 'original' file from a dummy
span - if the file id changed (e.g. due to being moved on disk), we would get an
ICE, since the Span was still valid due to its hash being unchanged.

…=jonas-schievink

⬆️ rust-analyzer