Implements
https://github.com/typescript-eslint/typescript-eslint/issues/2998
The copy of props feels wrong, but could not get it working otherwise
with the box and borrow things 😅
Also I found that TSImportType was missing some entries for visitors and
codegen.
In the case of codegen I'm not really understand the need as all the
types seems to be dismissed?
Change behavior of `byte_search!` macro, to make it easier to understand and use:
1. `handle_match` removed. Macro instead evaluates to the first matching byte.
2. `handle_eof` does not return from enclosing function.
3. Alter syntax to make clear that `continue_if` and `handle_eof` are not closures, so can use `return` statements in them.
These changes enabled by #2552.
This PR greatly simplifies the `byte_search!` macro.
Mainly removing `cold_branch()` from the "not enough bytes remaining for a batch" branch, which allows refactoring so that `handle_match` and `continue_if` don't need to be repeated twice.
Result for performance is inconsistent - a little better on some benchmarks, a little worse on others. But not by significant amounts either way. In my view, the benefit of making the macro simpler outweighs a small speed loss anyway.
Speed up lexing template strings.
This was the last use of `AutoCow` remaining in the lexer, and it's now removed.
Implementation is quite complex, to avoid repeatedly branching on whether an unescaped string is required or not (the way `AutoCow` did). I tried to simplify it down to a single function, but this hurt performance significantly.
Benchmarks do not show much movement, but I believe that's because there aren't many template strings in the benchmarks. Where there are template strings, I believe this speeds up lexing them significantly.
Simplify lexing JSX string attributes. As the search is purely for 1
byte value (the closing quote), and so doesn't require a byte table, use
`memchr`.
This change doesn't really register on benchmarks, but it's one step
closer to removing `AutoCow`, and transitioning all the searches in the
lexer to byte-by-byte.
This gets all the new TS types working to the same level TS output was
before and fixes a bunch of other codegen
---------
Co-authored-by: Boshen <boshenc@gmail.com>
1. Remove the check implementation of the parser
2. Implement it to semantic checker
3. Support typescript's check for duplicate class elements
Support checking for duplicate class elements in semantic checker is
easier to support typescript checking rules.
#2439 made using `continue_if` in `byte_search!` macro safe, as it no longer continues the main loop after a match, so no danger of reading out of bounds if `continue_if` code fast-forwards the current position.
This follow-on PR removes the unsafe blocks, and uses that fast-forward ability in a couple of places.
Refactor `byte_search!` macro to move logic out of the main loop. This ensures the compiler unrolls the loop.
This speeds up lexing single-line comments by 20%-25% on the benchmarks which contain enough comments for the change to register. Presumably the loop wasn't unrolled previously.
The code required to do this is a little odd. It adds an extra `loop {}` which always exits on the first turn (so not really a useful loop), but is required to be able to use `break` to exit that "loop", making 2 different paths for (1) matching byte found and (2) `for` loop completed without finding any match.
This is only way I could find to produce this behavior without using a macro. Is there a more "normal" way to get the same logic?
Catch all illegal UTF-8 bytes with the `UER` byte handler.
From https://datatracker.ietf.org/doc/html/rfc3629:
> The octet values C0, C1, F5 to FF never appear.
This change *should* make no difference at all, as a valid `&str` may not contain any of these byte values anyway. But it's possible if user has e.g. created the string with `str::from_utf8_unchecked` and not obeyed the safety contraints. This will at least contain the damage if that's happened, and panic rather than lead to UB. And since we're already catching other error conditions, may as well catch them all.
Consume multi-line comments faster.
* Initially search for `*/`, `\r`, `\n` or `0xE2` (first byte of
irregular line breaks).
* Once a line break is found, switch to faster search which only looks
for `*/`, as it's not relevant whether there are more line breaks or
not.
Using `memchr` for the 2nd simpler search, as it's efficient for a
search with only one "needle".
Initializing `memchr::memmem::Finder` is fairly expensive, and tried
numerous ways to handle it. This is most performant way I could find.
Any ideas how to avoid re-creating it for each Lexer pass? (it can't be
a `static` as `Finder::new` is not a const function, and `lazy_static!`
is too costly)
