The reader itself doesn't need ability to peek tokens, so it's better
if clients implement this functionality.
This hopefully becomes especially easy once we use iterator interface
for lexer, but this is not too easy at the moment, because of buffered
errors.
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
lexer: Disallow bare CR in raw byte strings
Handles bare CR ~but doesn't translate `\r\n` to `\n` yet in raw strings yet~ and translates CRLF to LF in raw strings.
As a side-note I think it'd be good to change the `unescape_` to return plain iterators to reduce some boilerplate (e.g. `has_error` could benefit from collecting `Result<T>` and aborting early on errors) but will do that separately, unless I missed something here that prevents it.
@matklad @petrochenkov thoughts?
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`.
It was commented out as part of
8a8e497ae7.
Done probably by accident, since the code in question was moved to a
match arm, along with newly introduced logic to detect bare CRs in raw
strings.
