Remove `ast::Guard`
With the introduction of `ast::ExprKind::Let` in https://github.com/rust-lang/rust/pull/60861, the `ast::Guard` structure is now redundant in terms of representing [`if let` guards](https://github.com/rust-lang/rust/issues/51114) in AST since it can be represented by `ExprKind::Let` syntactically. Therefore, we remove `ast::Guard` here.
However, we keep `hir::Guard` because the semantic representation is a different matter and this story is more unclear right now (might involve `goto 'arm` in HIR or something...).
r? @petrochenkov
Special-case literals in `parse_bottom_expr`.
This makes parsing faster, particularly for code with large constants,
for two reasons:
- it skips all the keyword comparisons for literals;
- it skips the allocation done by the `mk_expr` call in
`parse_literal_maybe_minus`.
r? @petrochenkov
Allow attributes in formal function parameters
Implements https://github.com/rust-lang/rust/issues/60406.
This is my first contribution to the compiler and since this is a large and complex project, I am not fully aware of the consequences of the changes I have made.
**TODO**
- [x] Forbid some built-in attributes.
- [x] Expand cfg/cfg_attr
This makes parsing faster, particularly for code with large constants,
for two reasons:
- it skips all the keyword comparisons for literals;
- it replaces the unnecessary `parse_literal_maybe_minus` call with
`parse_lit`, avoiding an unnecessary allocation via `mk_expr`.
The commit combines two calls into one by saving the result in a local
variable. The commit also moves the check for `async` later, so that
when a different keyword is present the `rust_2018` call will be avoided
completely.
Re-implement async fn drop order lowering
This PR re-implements the async fn drop order lowering changes so
that it all takes place in HIR lowering, building atop the work done by
@eddyb to refactor `Res::Upvar`.
Previously, this types involved in the lowering were constructed in
libsyntax as they had to be used during name resolution and HIR
lowering. This was awful because none of that logic should have existed
in libsyntax.
This commit also changes `ArgSource` to keep a `HirId` to the original
argument pattern rather than a cloned copy of the pattern.
Only b7aa4ed and 71fb8fa should be reviewed, any other commits
are from #61276 (though 447e336 might end up staying in this PR).
As a nice side effect, it also fixes#61187 (cc #61192).
r? @eddyb
cc @cramertj
Here follows the main reverts applied in order to make this commit:
Revert "Rollup merge of #60676 - davidtwco:issue-60674, r=cramertj"
This reverts commit 45b09453db, reversing
changes made to f6df1f6c30.
Revert "Rollup merge of #60437 - davidtwco:issue-60236, r=nikomatsakis"
This reverts commit 16939a50ea, reversing
changes made to 12bf981552.
Revert "Rollup merge of #59823 - davidtwco:issue-54716, r=cramertj"
This reverts commit 62d1574876, reversing
changes made to 4eff8526a7.
Point at individual type args on arg count mismatch
- Point at individual type arguments on arg count mismatch
- Make generics always have a valid span, even when there are no args
- Explain that `impl Trait` introduces an implicit type argument
Fix#55991.
