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|
# Assists
Cursor position or selection is signified by `┃` character.
## `add_derive`
Adds a new `#[derive()]` clause to a struct or enum.
```rust
// BEFORE
struct Point {
x: u32,
y: u32,┃
}
// AFTER
#[derive()]
struct Point {
x: u32,
y: u32,
}
```
## `add_explicit_type`
Specify type for a let binding.
```rust
// BEFORE
fn main() {
let x┃ = 92;
}
// AFTER
fn main() {
let x: i32 = 92;
}
```
## `add_impl`
Adds a new inherent impl for a type.
```rust
// BEFORE
struct Ctx<T: Clone> {
data: T,┃
}
// AFTER
struct Ctx<T: Clone> {
data: T,
}
impl<T: Clone> Ctx<T> {
}
```
## `add_impl_default_members`
Adds scaffold for overriding default impl members.
```rust
// BEFORE
trait T {
Type X;
fn foo(&self);
fn bar(&self) {}
}
impl T for () {
Type X = ();
fn foo(&self) {}┃
}
// AFTER
trait T {
Type X;
fn foo(&self);
fn bar(&self) {}
}
impl T for () {
Type X = ();
fn foo(&self) {}
fn bar(&self) {}
}
```
## `add_impl_missing_members`
Adds scaffold for required impl members.
```rust
// BEFORE
trait T {
Type X;
fn foo(&self);
fn bar(&self) {}
}
impl T for () {┃
}
// AFTER
trait T {
Type X;
fn foo(&self);
fn bar(&self) {}
}
impl T for () {
fn foo(&self) { unimplemented!() }
}
```
## `apply_demorgan`
Apply [De Morgan's law](https://en.wikipedia.org/wiki/De_Morgan%27s_laws).
This transforms expressions of the form `!l || !r` into `!(l && r)`.
This also works with `&&`. This assist can only be applied with the cursor
on either `||` or `&&`, with both operands being a negation of some kind.
This means something of the form `!x` or `x != y`.
```rust
// BEFORE
fn main() {
if x != 4 ||┃ !y {}
}
// AFTER
fn main() {
if !(x == 4 && y) {}
}
```
## `change_visibility`
Adds or changes existing visibility specifier.
```rust
// BEFORE
┃fn frobnicate() {}
// AFTER
pub(crate) fn frobnicate() {}
```
## `convert_to_guarded_return`
Replace a large conditional with a guarded return.
```rust
// BEFORE
fn main() {
┃if cond {
foo();
bar();
}
}
// AFTER
fn main() {
if !cond {
return;
}
foo();
bar();
}
```
## `fill_match_arms`
Adds missing clauses to a `match` expression.
```rust
// BEFORE
enum Action { Move { distance: u32 }, Stop }
fn handle(action: Action) {
match action {
┃
}
}
// AFTER
enum Action { Move { distance: u32 }, Stop }
fn handle(action: Action) {
match action {
Action::Move { distance } => (),
Action::Stop => (),
}
}
```
## `flip_binexpr`
Flips operands of a binary expression.
```rust
// BEFORE
fn main() {
let _ = 90 +┃ 2;
}
// AFTER
fn main() {
let _ = 2 + 90;
}
```
## `flip_comma`
Flips two comma-separated items.
```rust
// BEFORE
fn main() {
((1, 2),┃ (3, 4));
}
// AFTER
fn main() {
((3, 4), (1, 2));
}
```
## `inline_local_variable`
Inlines local variable.
```rust
// BEFORE
fn main() {
let x┃ = 1 + 2;
x * 4;
}
// AFTER
fn main() {
(1 + 2) * 4;
}
```
## `introduce_variable`
Extracts subexpression into a variable.
```rust
// BEFORE
fn main() {
┃(1 + 2)┃ * 4;
}
// AFTER
fn main() {
let var_name = (1 + 2);
var_name * 4;
}
```
|
