## Why
Due to the usage of `&'alloc mut T` in `oxc_allocator::Box`, and
`bumpalo::collections::Vec` in `oxc_allocator::Vec`, ast types are
currently invariant over their allocator lifetime `'a`. This prevents
`ouroboros` from generating `borrow_*` on ast type fields, leading to
the unfriendly `with_*` api:
c250b288ef/crates/oxc_parser/examples/multi-thread.rs (L82-L84)
## How
- For `oxc_allocator::Vec`, switch to `allocator_api2::vec::Vec`, which
has a covariant relationship with the allocator lifetime.
- For `oxc_allocator::Box`, use `std::ptr::NonNull` which is
specifically designed to be covariant. I don't use
`allocator_api2::boxed::Box` because it holds the allocator for
dropping, so the size is bigger.
## Downside
Now that `oxc_allocator::Box` uses the unsafe `NonNull`. It has to be a
private field to be safe. This make it impossible to do `Box(....)`
pattern matching.
This is one point where Babel and TSESLint diverge. For linter purposes
TSESLint structure makes more sense and that the reason of
https://github.com/typescript-eslint/typescript-eslint/issues/4130
The remaining `is_export` was creating redundant information and made
prettier (and the WIP oxc/prettier) print the AST of `export import X =
Y` as `export export import X = Y`.
> A Use Strict Directive may not contain an EscapeSequence or
LineContinuation.
It is `Use Strict Directive` spec, but the `expression` of `Directive`
isn't original string value, it has error if using it to codegen, so
here using `directive` of `Directive` to codegen and not to escape it.
Here is crashed test cases.
``` js
'use str\
ict';
```
The babel will print the original string, I follow it and avoid using
`print_str` because it will escape string.
I also changed some code using the `expression` of `Directive` to check
`Use Strict Directive` .
Parser, trivias and trivias_builder were edited to get all whitespaces.
Now Trivias struct store comments and whitespaces Vec. After that, i
will implement the no-irregular-whitespace rule.
P.S.: There isn't a way to implement this feature without lose a little
bit of performance, comparing with my last PR #1819 to minimax this
trouble instead of store the irregular whitespace as Span it was stored
as u32, i removed a map iterator and removed too a unused function. If
you have a suggestion about it pls give me a feedback.
