The LLVM build system is somewhat picky about which Python is used to build it
as it's known to be incompatible with the default `python2` package that ships
with MinGW. This was previously detected for MSVC builds but the logic was left
out for MinGW by accident (now that we've switched to cmake builds for LLVM
everywhere).
This corrects the `./configure` check and also updates the `README.md`
accordingly. Additionally, a number of instructions were updated to work with
the most recent copy of MSYS2.
Closes#34489
Batch up libsyntax breaking changes
Batch of the following syntax-[breaking-change] changes:
- #34213: Add a variant `Macro` to `TraitItemKind`
- #34368: Merge the variant `QPath` of `PatKind` into the variant `PatKind::Path`
- #34385: Move `syntax::ast::TokenTree` into a new module `syntax::tokenstream`
- #33943:
- Remove the type parameter from `visit::Visitor`
- Remove `attr::WithAttrs` -- use `attr::HasAttrs` instead.
- Change `fold_tt`/`fold_tts` to take token trees by value and avoid wrapping token trees in `Rc`.
- Remove the field `ctxt` of `ast::Mac_`
- Remove inherent method `attrs()` of types -- use the method `attrs` of `HasAttrs` instead.
- #34316:
- Remove `ast::Decl`/`ast::DeclKind` and add variants `Local` and `Item` to `StmtKind`.
- Move the node id for statements from the `StmtKind` variants to a field of `Stmt` (making `Stmt` a struct instead of an alias for `Spanned<StmtKind>`)
- Rename `ast::ExprKind::Again` to `Continue`.
- #34339: Generalize and abstract `ThinAttributes` to `ThinVec<Attribute>`
- Use `.into()` in convert between `Vec<Attribute>` and `ThinVec<Attribute>`
- Use autoderef instead of `.as_attr_slice()`
- #34436: Remove the optional expression from `ast::Block` and instead use a `StmtKind::Expr` at the end of the statement list.
- #34403: Move errors into a separate crate (unlikely to cause breakage)
grammatical: "Here's" should be "Here are", "rules" is plural.
stylistic: "rules for" is more idiomatic than "rules about".
grammatical: No verb in "One or the other"; changed to "It's one or the other".
code: added implied `fn main() { ... }` because it is referenced in "note: previous borrow ends here"
semantic: "But" seems like the wrong word here, there is now, contrast, only further explanation. "so", "thus" or "therefor" is clearer.
grammatical: Another misuse of "Here's", should be "Here are" (or possibly "Here're").
grammatical: "use" should be capitalized. All other subheadings capitalize the first word.
[MIR] Add Dominators to MIR and Add Graph Algorithms
~~This PR assumes PR #34149 lands.~~
Add generic graph algorithms to rustc_data_structures.
Add dominators and successors to the ~~cache (that currently only holds predecessors).~~ `Mir`.
Remove the return_address intrinsic.
This intrinsic to get the return pointer was introduced in #16248 / #16081 by @pcwalton for Servo.
However, as explained in #34227, it's impossible to ensure it's used correctly, and it broke with `-Zorbit`.
Servo's usage is being replaced in servo/servo#11872, and I expect nobody else to have abused it.
But I've also started a crater run, just in case this is a `[breaking-change]` for anyone else.
To allow these braced macro invocation, this PR removes the optional expression from `ast::Block` and instead uses a `StmtKind::Expr` at the end of the statement list.
Currently, braced macro invocations in blocks can expand into statements (and items) except when they are last in a block, in which case they can only expand into expressions.
For example,
```rust
macro_rules! make_stmt {
() => { let x = 0; }
}
fn f() {
make_stmt! {} //< This is OK...
let x = 0; //< ... unless this line is commented out.
}
```
Fixes#34418.
syntax-[breaking-change] cc #31645
(Only breaking because ast::TokenTree is now tokenstream::TokenTree.)
This pull request refactors TokenTrees into their own file as src/libsyntax/tokenstream.rs, moving them out of src/libsyntax/ast.rs, in order to prepare for an accompanying TokenStream implementation (per RFC 1566).
This PR refactors the 'errors' part of libsyntax into its own crate (librustc_errors). This is the first part of a few refactorings to simplify error reporting and potentially support more output formats (like a standardized JSON output and possibly an --explain mode that can work with the user's code), though this PR stands on its own and doesn't assume further changes.
As part of separating out the errors crate, I have also refactored the code position portion of codemap into its own crate (libsyntax_pos). While it's helpful to have the common code positions in a separate crate for the new errors crate, this may also enable further simplifications in the future.
**syntax-[breaking-change]** cc #31645
New `TraitItemKind::Macro` variant
This change adds support for macro expansion inside trait items by adding the new `TraitItemKind::Macro` and associated parsing code.
Renames "lets_do_this" macro more appropriately.
The macro gets used to create a mapping of identifiers to names and their
associated functions. Since it creates a table of language items, let's rename
it in a similar manner to how vec! creates a vec.
