oxc/crates/oxc_allocator/Cargo.toml
branchseer f159f60084
Make ast types covariant over the allocator lifetime. (#2943)
## 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.
2024-04-12 18:12:18 +08:00

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TOML

[package]
name = "oxc_allocator"
version = "0.12.3"
authors.workspace = true
description.workspace = true
edition.workspace = true
homepage.workspace = true
keywords.workspace = true
license.workspace = true
repository.workspace = true
rust-version.workspace = true
categories.workspace = true
[lints]
workspace = true
[lib]
doctest = false
[dependencies]
bumpalo = { workspace = true, features = ["collections", "allocator-api2"] }
serde = { workspace = true }
allocator-api2 = { workspace = true }
[dev-dependencies]
serde_json = { workspace = true }