# Objective
- Fixes#6370
- Closes#6581
## Solution
- Added the following lints to the workspace:
- `std_instead_of_core`
- `std_instead_of_alloc`
- `alloc_instead_of_core`
- Used `cargo +nightly fmt` with [item level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Item%5C%3A)
to split all `use` statements into single items.
- Used `cargo clippy --workspace --all-targets --all-features --fix
--allow-dirty` to _attempt_ to resolve the new linting issues, and
intervened where the lint was unable to resolve the issue automatically
(usually due to needing an `extern crate alloc;` statement in a crate
root).
- Manually removed certain uses of `std` where negative feature gating
prevented `--all-features` from finding the offending uses.
- Used `cargo +nightly fmt` with [crate level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Crate%5C%3A)
to re-merge all `use` statements matching Bevy's previous styling.
- Manually fixed cases where the `fmt` tool could not re-merge `use`
statements due to conditional compilation attributes.
## Testing
- Ran CI locally
## Migration Guide
The MSRV is now 1.81. Please update to this version or higher.
## Notes
- This is a _massive_ change to try and push through, which is why I've
outlined the semi-automatic steps I used to create this PR, in case this
fails and someone else tries again in the future.
- Making this change has no impact on user code, but does mean Bevy
contributors will be warned to use `core` and `alloc` instead of `std`
where possible.
- This lint is a critical first step towards investigating `no_std`
options for Bevy.
---------
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
- Fixes#14924
- Closes#9584
## Solution
- We introduce a new trait, `SystemInput`, that serves as a type
function from the `'static` form of the input, to its lifetime'd
version, similarly to `SystemParam` or `WorldQuery`.
- System functions now take the lifetime'd wrapped version,
`SystemInput::Param<'_>`, which prevents the issue presented in #14924
(i.e. `InRef<T>`).
- Functions for running systems now take the lifetime'd unwrapped
version, `SystemInput::Inner<'_>` (i.e. `&T`).
- Due to the above change, system piping had to be re-implemented as a
standalone type, rather than `CombinatorSystem` as it was previously.
- Removes the `Trigger<'static, E, B>` transmute in observer runner
code.
## Testing
- All current tests pass.
- Added additional tests and doc-tests.
---
## Showcase
```rust
let mut world = World::new();
let mut value = 2;
// Currently possible:
fn square(In(input): In<usize>) -> usize {
input * input
}
value = world.run_system_once_with(value, square);
// Now possible:
fn square_mut(InMut(input): InMut<usize>) {
*input *= *input;
}
world.run_system_once_with(&mut value, square_mut);
// Or:
fn square_ref(InRef(input): InRef<usize>) -> usize {
*input * *input
}
value = world.run_system_once_with(&value, square_ref);
```
## Migration Guide
- All current explicit usages of the following types must be changed in
the way specified:
- `SystemId<I, O>` to `SystemId<In<I>, O>`
- `System<In = T>` to `System<In = In<T>>`
- `IntoSystem<I, O, M>` to `IntoSystem<In<I>, O, M>`
- `Condition<M, T>` to `Condition<M, In<T>>`
- `In<Trigger<E, B>>` is no longer a valid input parameter type. Use
`Trigger<E, B>` directly, instead.
---------
Co-authored-by: Giacomo Stevanato <giaco.stevanato@gmail.com>
