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)
[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`.
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.
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.
Pretty-print attributes on tuple structs and add tests
This adds support to the pretty printer to print attributes added to tuple struct elements. Furthermore, it adds a test that makes sure we will print attributes on all variant data types.
This adds support to the pretty printer to print attributes
added to tuple struct elements. Furthermore, it adds a test
that makes sure we will print attributes on all variant data
types.
prefer `if let` to match with `None => ()` arm in some places
Casual grepping revealed some places in the codebase (some of which
antedated `if let`'s December 2014 stabilization in c200ae5a) where we
were using a match with a `None => ()` arm where (in the present
author's opinion) an `if let` conditional would be more readable. (Other
places where matching to the unit value did seem to better express the
intent were left alone.)
It's likely that we don't care about making such trivial,
non-functional, sheerly æsthetic changes.
But if we do, this is a patch.
Casual grepping revealed some places in the codebase (some of which
antedated `if let`'s December 2014 stabilization in c200ae5a) where we
were using a match with a `None => ()` arm where (in the present
author's opinion) an `if let` conditional would be more readable. (Other
places where matching to the unit value did seem to better express the
intent were left alone.)
It's likely that we don't care about making such trivial,
non-functional, sheerly æsthetic changes.
But if we do, this is a patch.
It turns out that the subsequent lines of the error message comment
should be aligned like this.
The "turns the corresponding compiler warning" language may not be
strictly the most accurate—a lint check isn't the same as a compiler
warning; it emits a compiler warning if it's set to the `warn` level—
but it may be worth glossing over such distinctions in favor of simple,
familar phrasings for the sake of pedagogy; thanks to Guillaume Gomez
for the wording suggestion.
Let's also fix up the introductory clauses of the sentences about how to
fix the error to put a little more emphasis on the fact that the
`forbid` setting was probably there for a reason.
