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
Identify when a stmt could have been parsed as an expr
There are some expressions that can be parsed as a statement without
a trailing semicolon depending on the context, which can lead to
confusing errors due to the same looking code being accepted in some
places and not others. Identify these cases and suggest enclosing in
parenthesis making the parse non-ambiguous without changing the
accepted grammar.
Fix#54186, cc #54482, fix#59975, fix#47287.
Currently, we deal with escape sequences twice: once when we lex a
string, and a second time when we unescape literals. This PR aims to
remove this duplication, by introducing a new `unescape` mode as a
single source of truth for character escaping rules
There are some expressions that can be parsed as a statement without
a trailing semicolon depending on the context, which can lead to
confusing errors due to the same looking code being accepted in some
places and not others. Identify these cases and suggest enclosing in
parenthesis making the parse non-ambiguous without changing the
accepted grammar.
Rename rustc_errors dependency in rust 2018 crates
I think this is a better solution than `use rustc_errors as errors` in `lib.rs` and `use crate::errors` in modules.
Related: rust-lang/cargo#5653
cc #58099
r? @Centril
rustdoc: overhaul code block lexing errors
Fixes#53919.
This PR moves the reporting of code block lexing errors from rendering time to an early pass, so we can use the compiler's error reporting mechanisms. This dramatically improves the diagnostics in this situation: we now de-emphasize the lexing errors as a note under a warning that has a span and suggestion instead of just emitting errors at the top level.
Additionally, this PR generalizes the markdown -> source span calculation function, which should allow other rustdoc warnings to use better spans in the future.
Last, the PR makes sure that the code block is always emitted in the docs, even if it fails to highlight correctly.
Of note:
- The new pass unfortunately adds another pass over the docs to gather the doc blocks for syntax-checking. I wonder if this could be combined with the pass that looks for testable blocks? I'm not familiar with that code, so I don't know how feasible that is.
- `pulldown_cmark` doesn't make it easy to find the spans of the code blocks, so the code that calculates the spans is a little nasty. It works for all the test cases I threw at it, but I wouldn't be surprised if an edge case would break it. Should have a thorough review.
- This PR worsens the state of #56885, since those certain fatal lexing errors are now emitted before docs get generated at all.
Modify some parser diagnostics to continue evaluating beyond the parser
Continue evaluating further errors after parser errors on:
- trailing type argument attribute
- lifetime in incorrect location
- incorrect binary literal
- missing `for` in `impl Trait for Foo`
- type argument in `where` clause
- incorrect float literal
- incorrect `..` in pattern
- associated types
- incorrect discriminator value variant error
and others. All of these were found by making `continue-parse-after-error` `true` by default to identify errors that would need few changes. There are now only a handful of errors that have any change with `continue-parse-after-error` enabled.
These changes make it so `rust` _won't_ stop evaluation after finishing parsing, enabling type checking errors to be displayed on the existing code without having to fix the parse errors.
Each commit has an individual diagnostic change with their corresponding tests.
CC #48724.
`TokenStream` is currently recursive in *two* ways:
- the `TokenTree` variant contains a `ThinTokenStream`, which can
contain a `TokenStream`;
- the `TokenStream` variant contains a `Vec<TokenStream>`.
The latter is not necessary and causes significant complexity. This
commit replaces it with the simpler `Vec<(TokenTree, IsJoint)>`.
This reduces complexity significantly. In particular, `StreamCursor` is
eliminated, and `Cursor` becomes much simpler, consisting now of just a
`TokenStream` and an index.
The commit also removes the `Extend` impl for `TokenStream`, because it
is only used in tests. (The commit also removes those tests.)
Overall, the commit reduces the number of lines of code by almost 200.
