Add match arm scopes and other scope fixes
* Add drop and lint scopes for match arms.
* Lint attributes are now respected on match arms.
* Make sure we emit a StorageDead if we diverge when initializing a temporary.
* Adjust MIR pretty printing of scopes for locals.
* Don't generate duplicate lint scopes for `let statements`.
* Add some previously missing fake borrows for matches.
closes#46525
cc @rust-lang/compiler
Simplify use of keyword symbols
They mirror non-keyword symbols now (see https://github.com/rust-lang/rust/pull/60630).
`keywords::MyKeyword.name()` -> `kw::MyKeyword`
`keywords::MyKeyword.ident()` -> `Ident::with_empty_ctxt(kw::MyKeyword)` (not common)
`keywords::Invalid.ident()` -> `Ident::invalid()` (more common)
Keywords are simply `Symbol` constants now, the `Keyword` struct is eliminated.
This means `kw::MyKeyword` can now be used in `match` in particular.
This allows types like Option<NonZeroU8> to be used in FFI without triggering the improper_ctypes lint. This works by changing the is_repr_nullable_ptr function to consider an enum E to be FFI-safe if:
- E has no explicit #[repr(...)].
- It only has two variants.
- One of those variants is empty (meaning it has no fields).
- The other variant has only one field.
- That field is one of the following:
- &T
- &mut T
- extern "C" fn
- core::num::NonZero*
- core::ptr::NonNull<T>
- #[repr(transparent)] struct wrapper around one of the types in this list.
- The size of E and its field are both known and are both the same size (implying E is participating in the nonnull optimization).
Ban multi-trait objects via trait aliases
Obviously, multi-trait objects are not normally supported, so they should not be supported via trait aliases.
This has been factored out from the previous PR https://github.com/rust-lang/rust/pull/55994 (see point 1).
r? @Centril
CC @nikomatsakis
------------------
### RELNOTES:
We now allow `dyn Send + fmt::Debug` with equivalent semantics to `dyn fmt::Debug + Send`.
That is, the order of the mentioned traits does not matter wrt. principal/not-principal traits.
This is a small change that might deserve a mention in the blog post because it is a language change but most likely not.
See ce2ee305f9/src/test/ui/traits/wf-trait-object-reverse-order.rs.
// @Centril
Add stream_to_parser_with_base_dir
This PR adds `stream_to_parser_with_base_dir`, which creates a parser from a token stream and a base directory.
Context: I would like to parse `cfg_if!` macro and get a list of modules defined inside it from rustfmt so that rustfmt can format those modules (cc https://github.com/rust-lang/rustfmt/issues/3253). To do so, I need to create a parser from `TokenStream` and set the directory of `Parser` to the same directory as the parent directory of a file which contains `cfg_if!` invocation. AFAIK there is no way to achieve this, and hence this PR.
Alternatively, I could change the visibility of `Parser.directory` from `crate` to `pub` so that the value can be modified after initializing a parser. I don't have a preference over either approach (or others, as long as it works).
Move gensym operations from `Symbol` to `Ident`
Gensyms are always at the `Ident` level, and long-term we probably want to record gensym-ness in hygiene data.
r? @petrochenkov
rustc: Improve type size assertions
Now they
- Tell what the new size is, when it changes
- Do not require passing an identifier
```
::: src\libsyntax\parse\token.rs:223:1
|
223 | static_assert_size!(Token, 123);
| -------------------------------- in this macro invocation
|
= note: expected type `[(); 123]`
found type `[(); 16]`
```
Note that the `is_gensymed` call on `primitive_types` is unnecessary
because that table only contains the name of primitive types (e.g.
`i32`) and never contains gensyms.
Include expression to wait for to the span of Await
Currently the span of `await!` only includes itself:
```rust
await!(3);
// ^^^^^
```
This PR changes it so that the span holds the whole `await!` expression:
```rust
await!(3);
// ^^^^^^^^^
Move token tree related lexer state to a separate struct
Just a types-based refactoring.
We only used a bunch of fields when tokenizing into a token tree, so let's move them out of the base lexer
Use `Symbol` more
A `Symbol` can be equated with a string (e.g. `&str`). This involves a
TLS lookup to get the chars (and a Mutex lock in a parallel compiler)
and then a char-by-char comparison. This functionality is convenient but
avoids one of the main benefits of `Symbol`s, which is fast equality
comparisons.
This PR removes the `Symbol`/string equality operations, forcing a lot
of existing string occurrences to become `Symbol`s. Fortunately, these
are almost all static strings (many are attribute names) and we can add
static `Symbol`s as necessary, and very little extra interning occurs.
The benefits are (a) a slight speedup (possibly greater in a parallel
compiler), and (b) the code is a lot more principled about `Symbol` use.
The main downside is verbosity, particularly with more `use
syntax::symbol::symbols` items.
r? @Zoxc
