7687: Specialization for async traits r=matklad a=arnaudgolfouse
Fixes#7669.
Adapting the parser seemed to be all that was needed, but I am not very experienced with the codebase. Is this enough ?
Co-authored-by: Arnaud <arnaud.golfouse@laposte.net>
7620: Support control flow in `extract_function` assist r=matklad a=cpud36
Support `return`ing from outer function, `break`ing and `continue`ing outer loops when extracting function.
# Example
Transforms
```rust
fn foo() -> i32 {
let items = [1,2,3];
let mut sum = 0;
for &item in items {
<|>if item == 42 {
break;
}<|>
sum += item;
}
sum
}
```
Into
```rust
fn foo() -> i32 {
let items = [1,2,3];
let mut sum = 0;
for &item in items {
if fun_name(item) {
break;
}
sum += item;
}
sum
}
fn fun_name(item: i32) -> bool {
if item == 42 {
return true;
}
false
}
```
# Features
Supported variants
- break and function does not return => uses `bool` and plain if
- break and function does return => uses `Option<T>` and matches on it
- break with value and function does not return => uses `Option<T>` and if let
- break with value and function does return => uses `Result<T, U>` and matches on t
- same for `return` and `continue`(but we can't continue with value)
Assist does handle nested loops and nested items(like functions, modules, impls)
Try `expr?` operator is allowed together with `return Err(_)` and `return None`.
`return expr` is not allowed.
# Not supported
## Mixing `return` with `break` or `continue`
If we have e.g. a `return` and a `break` in the selected code, it is unclear what the produced code should look like.
We can try `Result<T, Option<U>>` or something like that, but it isn't idiomatic, nor it is established. Otherwise, implementation
is relatively simple.
## `break` with label
Not sure how to handle different labels for multiple `break`s.
[edit] implemented try `expr?`
Co-authored-by: Vladyslav Katasonov <cpud47@gmail.com>
7535: Extract function assist r=cpud36 a=cpud36
This PR adds `extract function/method` assist. closes#5409.
# Supported features
Assist should support extracting from expressions(`1`, `2 + 2`, `loop { }`) and from a series of statements, e.g.:
```rust
foo();
$0bar();
baz();$0
quix();
```
Assist also supports extracting parameters, like:
```rust
fn foo() -> i32 {
let n = 1;
$0n + 1$0
}
// -
fn foo() -> i32 {
let n = 1;
fun_name(n)
}
fn fun_name(n: i32) -> i32 {
n + 1
}
```
Extracting methods also generally works.
Assist allows referencing outer variables, both mutably and immutably, and handles handles access to variables local to extracted function:
```rust
fn foo() {
let mut n = 1;
let mut m = 2;
let mut moved_v = Vec::new();
let mut ref_mut_v = Vec::new();
$0
n += 1;
let k = 1;
moved_v.push(n);
let r = &mut m;
ref_mut_v.push(*r);
let h = 3;
$0
n = ref_mut_v.len() + k;
n -= h + m;
}
// -
fn foo() {
let mut n = 1;
let mut m = 2;
let mut moved_v = Vec::new();
let mut ref_mut_v = Vec::new();
let (k, h) = fun_name(&mut n, moved_v, &mut m, &mut ref_mut_v);
n = ref_mut_v.len() + k;
n -= h + m;
}
fn fun_name(n: &mut i32, mut moved_v: Vec<i32>, m: &mut i32, ref_mut_v: &mut Vec<i32>) -> (i32, i32) {
*n += 1;
let k = 1;
moved_v.push(*n);
let r = m;
ref_mut_v.push(*r);
let h = 3;
(k, h)
}
```
So we handle both input and output paramters
# Showcase
# Working with non-`Copy` types
Consider the following example:
```rust
fn foo() {
let v = Vec::new();
$0
let n = v.len();
$0
let is_empty = v.is_empty();
}
```
`v` must be a parameter to extracted function.
The question is, what type should it have.
It could be `v: Vec<i32>`, or `v: &Vec<i32>`.
The former is incorrect for `Vec<i32>`, but the later is silly for `i32`.
To resolve this we need to know if the type implements `Copy` trait.
I didn't find any api available from assists to query this.
`hir_ty::method_resolution::implements` seems relevant, but is isn't publicly re-exported from `hir`.
# Star(`*`) token and pointer dereference
If I understand correctly, in order to create expression like `*p`, one should use `ast::make::expr_prefix(T![*], ...)`, which
in turn calls `token(T![*])`.
`token` does not have star in `tokens::SOURCE_FILE`, so this panics.
I had to add `*` to `SOURCE_FILE` to make it work.
Correct me if this is not intended way to do this.
# Lowering access `value -> mut ref -> shared ref`
Consider the following example:
```rust
fn foo() {
let v = Vec::new();
$0 let n = v.len(); $0
}
```
`v` is not used after extracted function body, so both `v: &Vec<i32>` and `v: Vec<i32>` would work.
Currently the later would be chosen.
We can however check the body of extracted function and conclude that `v: &Vec<i32>` is sufficient.
Using `v: &Vec<i32>`(that is a minimal required access level) might be a better default.
I am unsure.
# Cleanup
The assist seems to be reasonably handling most of common cases.
If there are no concerns with code it produces(i.e. with test cases), I will start cleaning up
[edit]
added showcase
Co-authored-by: Vladyslav Katasonov <cpud47@gmail.com>
7291: Wrap remaining self/super/crate in Name{Ref} r=matklad a=Veykril
That should be the remaining special casing for `self` 🎉
Co-authored-by: Lukas Wirth <lukastw97@gmail.com>
7218: Fix typos r=Veykril a=regexident
Apart from the very last commit on this PR (which fixes a public type's name) all changes are non-breaking.
Co-authored-by: Vincent Esche <regexident@gmail.com>
