`SymbolFlags::ArrowFunction` is an oddity, as whether a symbol is an arrow function is not statically knowable. In the following cases, `f` symbol did not have `ArrowFunction` flag set:
```js
const {f} = {f: () => {}};
```
```js
let f = 123;
f = () => {};
```
`SymbolFlags::ArrowFunction` is therefore not particularly useful, and possibly misleading. Having it complicates the transformer, and it's not used anywhere in Oxc.
This PR removes it.
### Difference
In `enter_expression`: Recursive transform JSX
In `exit_expression`: Deep first transform
After the change, `transform_jsx` still has a lot of room for improvement.
I expect small performance regression.
But managed to improve the following case from react.developmement.js
```
oxc main ❯ diff before.js after.js
670c670
< if (!(dispatcher !== null)) throw Error("Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:\n1. You might have mismatching versions of React and the renderer (such as React DOM)\n2. You might be breaking the Rules of Hooks\n3. You might have more than one copy of React in the same app\nSee https://reactjs.org/link/invalid-hook-call for tips about how to debug and fix this problem.");
---
> if (dispatcher === null) throw Error("Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:\n1. You might have mismatching versions of React and the renderer (such as React DOM)\n2. You might be breaking the Rules of Hooks\n3. You might have more than one copy of React in the same app\nSee https://reactjs.org/link/invalid-hook-call for tips about how to debug and fix this problem.");
```
See https://babel.dev/docs/options#misc-options for background on `unambiguous`
Once `SourceType::Unambiguous` is parsed, it will correctly set the returned `Program::source_type` to either `module` or `script`.
This also removes the confusing `SourceType::always_strict` field.
I hacked it with `SourceType::always_strict`, but what we actually want is add `'use strict'`.
This is technically a breaking change but I don't expect anyone using this outside of oxc.
The snapshot has a large diff due to every single line shifting by 1 row :-/
related: #4754
The implementation port from [esbuild](332727499e/internal/js_parser/js_parser.go (L12820-L12840)). And cover all babel's regexp plugins
---
## The following description was generated by `Graphite` 😋
### TL;DR
Added support for transforming various RegExp features to ensure compatibility with older JavaScript environments.
### What changed?
- Implemented a new `RegExp` transformer to handle unsupported RegExp literal features
- Added options to control different RegExp transformations (e.g., sticky flag, unicode flag, dot-all flag, etc.)
- Updated the transformer to convert unsupported RegExp literals into `new RegExp()` constructor calls
- Added test cases for different RegExp transformations
- Integrated the new RegExp transformer into the existing transformation pipeline
### How to test?
1. Run the existing test suite to ensure no regressions
2. Execute the new RegExp-specific tests in the `tasks/transform_conformance/tests/esbuild-tests/test/fixtures/regexp/` directory
3. Try transforming code with various RegExp features using different target environments to verify correct transformations
close: #5435
The behavior of `IdentifierReference` in `TSPropertySignature` is the same as in `TSTypeQuery`, both allow only reference value bindings and type-only import bindings.
I still use `ReferenceFlags::TSTypeQuery` here because I want to avoid producing many changes unrelated to the bug in this PR. I will refactor it in the follow-up PR soon
This should be causing more negative tests to fail than it actually is. This is
because our typescript coverage tests use the "declarations" option to change
the source type to `.d.ts`, which is incorrect. This setting enables `.d.ts`
emits, it does not mean that input files should be treated as `.d.ts`
themselves.
#5223 added a new variant `JSXElementName::IdentifierReference` for JSX identifiers which are treated as references (e.g. `<Foo>`) as opposed to `JSXElementName::Identifier` which is for lowercase (e.g. `<div>`).
But we were incorrectly categorizing identifiers beginning with `_` or `$` - these should also be treated as references.
(as discussed in https://github.com/oxc-project/oxc/pull/5339#issuecomment-2321037779)
Follow-on after #5223.
JSX identifiers which start with a capital letter are now `JSXElementName::IdentifierReference`s, so no need to check for capitalized `JSXElementName::Identifier`s.
