Below you find a detailed visual guide on all the supported configuration options of rustfmt:
+## `array_width`
+
+Maximum width of an array literal before falling back to vertical formatting.
+
+- **Default value**: `60`
+- **Possible values**: any positive integer that is less than or equal to the value specified for [`max_width`](#max_width)
+- **Stable**: Yes
+
+By default this option is set as a percentage of [`max_width`](#max_width) provided by [`use_small_heuristics`](#use_small_heuristics), but a value set directly for `array_width` will take precedence.
+
+See also [`max_width`](#max_width) and [`use_small_heuristics`](#use_small_heuristics)
+
+## `attr_fn_like_width`
+
+Maximum width of the args of a function-like attributes before falling back to vertical formatting.
+
+- **Default value**: `70`
+- **Possible values**: any positive integer that is less than or equal to the value specified for [`max_width`](#max_width)
+- **Stable**: Yes
+
+By default this option is set as a percentage of [`max_width`](#max_width) provided by [`use_small_heuristics`](#use_small_heuristics), but a value set directly for `attr_fn_like_width` will take precedence.
+
+See also [`max_width`](#max_width) and [`use_small_heuristics`](#use_small_heuristics)
## `binop_separator`
- **Default value**: `"Front"`
- **Possible values**: `"Front"`, `"Back"`
-- **Stable**: No (tracking issue: #3368)
+- **Stable**: No (tracking issue: [#3368](https://github.com/rust-lang/rustfmt/issues/3368))
#### `"Front"` (default):
- **Default value**: `0`
- **Possible values**: *unsigned integer*
-- **Stable**: No (tracking issue: #3382)
+- **Stable**: No (tracking issue: [#3382](https://github.com/rust-lang/rustfmt/issues/3382))
### Example
Original Code (rustfmt will not change it with the default value of `0`):
- **Default value**: `1`
- **Possible values**: any non-negative integer
-- **Stable**: No (tracking issue: #3381)
+- **Stable**: No (tracking issue: [#3381](https://github.com/rust-lang/rustfmt/issues/3381))
### Example
Original Code:
- **Default value**: `"SameLineWhere"`
- **Possible values**: `"AlwaysNextLine"`, `"PreferSameLine"`, `"SameLineWhere"`
-- **Stable**: No (tracking issue: #3376)
+- **Stable**: No (tracking issue: [#3376](https://github.com/rust-lang/rustfmt/issues/3376))
### Functions
}
```
+## `chain_width`
+
+Maximum width of a chain to fit on one line.
+
+- **Default value**: `60`
+- **Possible values**: any positive integer that is less than or equal to the value specified for [`max_width`](#max_width)
+- **Stable**: Yes
+
+By default this option is set as a percentage of [`max_width`](#max_width) provided by [`use_small_heuristics`](#use_small_heuristics), but a value set directly for `chain_width` will take precedence.
+
+See also [`max_width`](#max_width) and [`use_small_heuristics`](#use_small_heuristics)
## `color`
- **Default value**: `"Auto"`
- **Possible values**: "Auto", "Always", "Never"
-- **Stable**: No (tracking issue: #3385)
+- **Stable**: No (tracking issue: [#3385](https://github.com/rust-lang/rustfmt/issues/3385))
## `combine_control_expr`
- **Default value**: `true`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3369)
+- **Stable**: No (tracking issue: [#3369](https://github.com/rust-lang/rustfmt/issues/3369))
#### `true` (default):
- **Default value**: `80`
- **Possible values**: any positive integer
-- **Stable**: No (tracking issue: #3349)
+- **Stable**: No (tracking issue: [#3349](https://github.com/rust-lang/rustfmt/issues/3349))
**Note:** A value of `0` results in [`wrap_comments`](#wrap_comments) being applied regardless of a line's width.
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3384)
+- **Stable**: No (tracking issue: [#3384](https://github.com/rust-lang/rustfmt/issues/3384))
#### `false` (default):
- **Default value**: `"AlwaysSameLine"`
- **Possible values**: `"AlwaysNextLine"`, `"AlwaysSameLine"`, `"ClosingNextLine"`
-- **Stable**: No (tracking issue: #3377)
+- **Stable**: No (tracking issue: [#3377](https://github.com/rust-lang/rustfmt/issues/3377))
#### `"AlwaysSameLine"` (default):
## `disable_all_formatting`
-Don't reformat anything
+Don't reformat anything.
+
+Note that this option may be soft-deprecated in the future once the [ignore](#ignore) option is stabilized. Nightly toolchain users are encouraged to use [ignore](#ignore) instead when possible.
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3388)
+- **Stable**: Yes
## `edition`
Specifies which edition is used by the parser.
-- **Default value**: `2015`
-- **Possible values**: `2015`, `2018`
+- **Default value**: `"2015"`
+- **Possible values**: `"2015"`, `"2018"`, `"2021"`
- **Stable**: Yes
Rustfmt is able to pick up the edition used by reading the `Cargo.toml` file if executed
- **Default value**: `true`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3356)
+- **Stable**: No (tracking issue: [#3356](https://github.com/rust-lang/rustfmt/issues/3356))
#### `true` (default):
- **Default value** : 0
- **Possible values**: any positive integer
-- **Stable**: No (tracking issue: #3372)
+- **Stable**: No (tracking issue: [#3372](https://github.com/rust-lang/rustfmt/issues/3372))
#### `0` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3391)
+- **Stable**: No (tracking issue: [#3391](https://github.com/rust-lang/rustfmt/issues/3391))
See also [`max_width`](#max_width).
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3392)
+- **Stable**: No (tracking issue: [#3392](https://github.com/rust-lang/rustfmt/issues/3392))
## `fn_args_layout`
}
```
+## `fn_call_width`
+
+Maximum width of the args of a function call before falling back to vertical formatting.
+
+- **Default value**: `60`
+- **Possible values**: any positive integer that is less than or equal to the value specified for [`max_width`](#max_width)
+- **Stable**: Yes
+
+By default this option is set as a percentage of [`max_width`](#max_width) provided by [`use_small_heuristics`](#use_small_heuristics), but a value set directly for `fn_call_width` will take precedence.
+
+See also [`max_width`](#max_width) and [`use_small_heuristics`](#use_small_heuristics)
## `fn_single_line`
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3358)
+- **Stable**: No (tracking issue: [#3358](https://github.com/rust-lang/rustfmt/issues/3358))
#### `false` (default):
- **Default value**: `false`
- **Possible values**: `false`, `true`
-- **Stable**: No (tracking issue: #3374)
+- **Stable**: No (tracking issue: [#3374](https://github.com/rust-lang/rustfmt/issues/3374))
#### `false` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3348)
+- **Stable**: No (tracking issue: [#3348](https://github.com/rust-lang/rustfmt/issues/3348))
#### `false` (default):
}
```
+## `format_generated_files`
+
+Format generated files. A file is considered generated
+if any of the first five lines contain a `@generated` comment marker.
+
+- **Default value**: `true`
+- **Possible values**: `true`, `false`
+- **Stable**: No (tracking issue: [#5080](https://github.com/rust-lang/rustfmt/issues/5080))
+
## `format_macro_matchers`
Format the metavariable matching patterns in macros.
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3354)
+- **Stable**: No (tracking issue: [#3354](https://github.com/rust-lang/rustfmt/issues/3354))
#### `false` (default):
- **Default value**: `true`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3355)
+- **Stable**: No (tracking issue: [#3355](https://github.com/rust-lang/rustfmt/issues/3355))
#### `true` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3353)
+- **Stable**: No (tracking issue: [#3353](https://github.com/rust-lang/rustfmt/issues/3353))
#### `false` (default):
See also: [`tab_spaces`](#tab_spaces).
+## `hex_literal_case`
+
+Control the case of the letters in hexadecimal literal values
+
+- **Default value**: `Preserve`
+- **Possible values**: `Upper`, `Lower`
+- **Stable**: No (tracking issue: [#5081](https://github.com/rust-lang/rustfmt/issues/5081))
## `hide_parse_errors`
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3390)
+- **Stable**: No (tracking issue: [#3390](https://github.com/rust-lang/rustfmt/issues/3390))
## `ignore`
- **Default value**: format every file
- **Possible values**: See an example below
-- **Stable**: No (tracking issue: #3395)
+- **Stable**: No (tracking issue: [#3395](https://github.com/rust-lang/rustfmt/issues/3395))
### Example
- **Default Value**: `"Block"`
- **Possible values**: `"Block"`, `"Visual"`
-- **Stable**: No (tracking issue: #3360)
+- **Stable**: No (tracking issue: [#3360](https://github.com/rust-lang/rustfmt/issues/3360))
#### `"Block"` (default):
- **Default value**: "Mixed"
- **Possible values**: "Horizontal", "HorizontalVertical", "Mixed", "Vertical"
-- **Stable**: No (tracking issue: #3361)
+- **Stable**: No (tracking issue: [#3361](https://github.com/rust-lang/rustfmt/issues/3361))
#### `"Mixed"` (default):
- **Default value**: `"Block"`
- **Possible values**: `"Block"`, `"Visual"`
-- **Stable**: No (tracking issue: #3346)
+- **Stable**: No (tracking issue: [#3346](https://github.com/rust-lang/rustfmt/issues/3346))
### Array
- **Default value**: 0
- **Possible values**: any positive integer
-- **Stable**: No (tracking issue: #3343)
+- **Stable**: No (tracking issue: [#3343](https://github.com/rust-lang/rustfmt/issues/3343))
### Example
- **Default value**: `""`
- **Possible values**: path to a license template file
-- **Stable**: No (tracking issue: #3352)
+- **Stable**: No (tracking issue: [#3352](https://github.com/rust-lang/rustfmt/issues/3352))
A license template is a plain text file which is matched literally against the
beginning of each source file, except for `{}`-delimited blocks, which are
## `match_arm_blocks`
-Wrap the body of arms in blocks when it does not fit on the same line with the pattern of arms
+Controls whether arm bodies are wrapped in cases where the first line of the body cannot fit on the same line as the `=>` operator.
+
+The Style Guide requires that bodies are block wrapped by default if a line break is required after the `=>`, but this option can be used to disable that behavior to prevent wrapping arm bodies in that event, so long as the body does not contain multiple statements nor line comments.
- **Default value**: `true`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3373)
+- **Stable**: No (tracking issue: [#3373](https://github.com/rust-lang/rustfmt/issues/3373))
#### `true` (default):
```rust
fn main() {
match lorem {
- true => {
+ ipsum => {
foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x)
}
- false => println!("{}", sit),
+ dolor => println!("{}", sit),
+ sit => foo(
+ "foooooooooooooooooooooooo",
+ "baaaaaaaaaaaaaaaaaaaaaaaarr",
+ "baaaaaaaaaaaaaaaaaaaazzzzzzzzzzzzz",
+ "qqqqqqqqquuuuuuuuuuuuuuuuuuuuuuuuuuxxx",
+ ),
}
}
```
```rust
fn main() {
match lorem {
- true =>
+ lorem =>
foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x),
- false => println!("{}", sit),
+ ipsum => println!("{}", sit),
+ sit => foo(
+ "foooooooooooooooooooooooo",
+ "baaaaaaaaaaaaaaaaaaaaaaaarr",
+ "baaaaaaaaaaaaaaaaaaaazzzzzzzzzzzzz",
+ "qqqqqqqqquuuuuuuuuuuuuuuuuuuuuuuuuuxxx",
+ ),
}
}
```
See also: [`match_block_trailing_comma`](#match_block_trailing_comma).
+## `match_arm_leading_pipes`
+
+Controls whether to include a leading pipe on match arms
+
+- **Default value**: `Never`
+- **Possible values**: `Always`, `Never`, `Preserve`
+- **Stable**: Yes
+
+#### `Never` (default):
+```rust
+// Leading pipes are removed from this:
+// fn foo() {
+// match foo {
+// | "foo" | "bar" => {}
+// | "baz"
+// | "something relatively long"
+// | "something really really really realllllllllllllly long" => println!("x"),
+// | "qux" => println!("y"),
+// _ => {}
+// }
+// }
+
+// Becomes
+fn foo() {
+ match foo {
+ "foo" | "bar" => {}
+ "baz"
+ | "something relatively long"
+ | "something really really really realllllllllllllly long" => println!("x"),
+ "qux" => println!("y"),
+ _ => {}
+ }
+}
+```
+
+#### `Always`:
+```rust
+// Leading pipes are emitted on all arms of this:
+// fn foo() {
+// match foo {
+// "foo" | "bar" => {}
+// "baz"
+// | "something relatively long"
+// | "something really really really realllllllllllllly long" => println!("x"),
+// "qux" => println!("y"),
+// _ => {}
+// }
+// }
+
+// Becomes:
+fn foo() {
+ match foo {
+ | "foo" | "bar" => {}
+ | "baz"
+ | "something relatively long"
+ | "something really really really realllllllllllllly long" => println!("x"),
+ | "qux" => println!("y"),
+ | _ => {}
+ }
+}
+```
+
+#### `Preserve`:
+```rust
+fn foo() {
+ match foo {
+ | "foo" | "bar" => {}
+ | "baz"
+ | "something relatively long"
+ | "something really really really realllllllllllllly long" => println!("x"),
+ | "qux" => println!("y"),
+ _ => {}
+ }
+
+ match baz {
+ "qux" => {}
+ "foo" | "bar" => {}
+ _ => {}
+ }
+}
+```
+
## `match_block_trailing_comma`
Put a trailing comma after a block based match arm (non-block arms are not affected)
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3380)
+- **Stable**: Yes
#### `false` (default):
#### `false`:
```rust
+#[derive(Eq, PartialEq, Debug, Copy, Clone)]
+pub enum Bar {}
+
#[derive(Eq, PartialEq)]
#[derive(Debug)]
#[derive(Copy, Clone)]
pub enum Foo {}
```
+## `imports_granularity`
+
+How imports should be grouped into `use` statements. Imports will be merged or split to the configured level of granularity.
+
+- **Default value**: `Preserve`
+- **Possible values**: `Preserve`, `Crate`, `Module`, `Item`, `One`
+- **Stable**: No (tracking issue: [#4991](https://github.com/rust-lang/rustfmt/issues/4991))
+
+#### `Preserve` (default):
+
+Do not change the granularity of any imports and preserve the original structure written by the developer.
+
+```rust
+use foo::b;
+use foo::b::{f, g};
+use foo::{a, c, d::e};
+use qux::{h, i};
+```
+
+#### `Crate`:
+
+Merge imports from the same crate into a single `use` statement. Conversely, imports from different crates are split into separate statements.
+
+```rust
+use foo::{
+ a, b,
+ b::{f, g},
+ c,
+ d::e,
+};
+use qux::{h, i};
+```
+
+#### `Module`:
+
+Merge imports from the same module into a single `use` statement. Conversely, imports from different modules are split into separate statements.
+
+```rust
+use foo::b::{f, g};
+use foo::d::e;
+use foo::{a, b, c};
+use qux::{h, i};
+```
+
+#### `Item`:
+
+Flatten imports so that each has its own `use` statement.
+
+```rust
+use foo::a;
+use foo::b;
+use foo::b::f;
+use foo::b::g;
+use foo::c;
+use foo::d::e;
+use qux::h;
+use qux::i;
+```
+
+#### `One`:
+
+Merge all imports into a single `use` statement as long as they have the same visibility.
+
+```rust
+pub use foo::{x, y};
+use {
+ bar::{
+ a,
+ b::{self, f, g},
+ c,
+ d::e,
+ },
+ qux::{h, i},
+};
+```
+
## `merge_imports`
-Merge multiple imports into a single nested import.
+This option is deprecated. Use `imports_granularity = "Crate"` instead.
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3362)
#### `false` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3350)
+- **Stable**: No (tracking issue: [#3350](https://github.com/rust-lang/rustfmt/issues/3350))
#### `false` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3351)
+- **Stable**: No (tracking issue: [#3351](https://github.com/rust-lang/rustfmt/issues/3351))
#### `false` (default):
#![doc = "Example documentation"]
#[doc = "Example item documentation"]
+pub enum Bar {}
+
+/// Example item documentation
pub enum Foo {}
```
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3370)
+- **Stable**: No (tracking issue: [#3370](https://github.com/rust-lang/rustfmt/issues/3370))
#### `false` (default):
#### `false`:
```rust
fn main() {
+ (foo());
+
((((foo()))));
}
```
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3363)
+- **Stable**: No (tracking issue: [#3363](https://github.com/rust-lang/rustfmt/issues/3363))
#### `false` (default)
type Item = i32;
}
+
+impl Iterator for Dummy {
+ type Item = i32;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ None
+ }
+}
```
#### `true`
use sit;
```
+## `group_imports`
+
+Controls the strategy for how imports are grouped together.
+
+- **Default value**: `Preserve`
+- **Possible values**: `Preserve`, `StdExternalCrate`, `One`
+- **Stable**: No (tracking issue: [#5083](https://github.com/rust-lang/rustfmt/issues/5083))
+
+#### `Preserve` (default):
+
+Preserve the source file's import groups.
+
+```rust
+use super::update::convert_publish_payload;
+use chrono::Utc;
+
+use alloc::alloc::Layout;
+use juniper::{FieldError, FieldResult};
+use uuid::Uuid;
+
+use std::sync::Arc;
+
+use broker::database::PooledConnection;
+
+use super::schema::{Context, Payload};
+use crate::models::Event;
+use core::f32;
+```
+
+#### `StdExternalCrate`:
+
+Discard existing import groups, and create three groups for:
+1. `std`, `core` and `alloc`,
+2. external crates,
+3. `self`, `super` and `crate` imports.
+
+```rust
+use alloc::alloc::Layout;
+use core::f32;
+use std::sync::Arc;
+
+use broker::database::PooledConnection;
+use chrono::Utc;
+use juniper::{FieldError, FieldResult};
+use uuid::Uuid;
+
+use super::schema::{Context, Payload};
+use super::update::convert_publish_payload;
+use crate::models::Event;
+```
+
+#### `One`:
+
+Discard existing import groups, and create a single group for everything
+
+```rust
+use super::schema::{Context, Payload};
+use super::update::convert_publish_payload;
+use crate::models::Event;
+use alloc::alloc::Layout;
+use broker::database::PooledConnection;
+use chrono::Utc;
+use core::f32;
+use juniper::{FieldError, FieldResult};
+use std::sync::Arc;
+use uuid::Uuid;
+```
## `reorder_modules`
- **Default value**: `"Never"`
- **Possible values**: `"Always"`, `"Unnumbered"`, `"Never"`
-- **Stable**: No (tracking issue: #3394)
+- **Stable**: No (tracking issue: [#3394](https://github.com/rust-lang/rustfmt/issues/3394))
Warns about any comments containing `FIXME` in them when set to `"Always"`. If
it contains a `#X` (with `X` being a number) in parentheses following the
- **Default value**: `"Never"`
- **Possible values**: `"Always"`, `"Unnumbered"`, `"Never"`
-- **Stable**: No (tracking issue: #3393)
+- **Stable**: No (tracking issue: [#3393](https://github.com/rust-lang/rustfmt/issues/3393))
Warns about any comments containing `TODO` in them when set to `"Always"`. If
it contains a `#X` (with `X` being a number) in parentheses following the
- **Default value**: `CARGO_PKG_VERSION`
- **Possible values**: any published version (e.g. `"0.3.8"`)
-- **Stable**: No (tracking issue: #3386)
+- **Stable**: No (tracking issue: [#3386](https://github.com/rust-lang/rustfmt/issues/3386))
## `skip_children`
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3389)
+- **Stable**: No (tracking issue: [#3389](https://github.com/rust-lang/rustfmt/issues/3386))
+
+## `single_line_if_else_max_width`
+
+Maximum line length for single line if-else expressions. A value of `0` (zero) results in if-else expressions always being broken into multiple lines. Note this occurs when `use_small_heuristics` is set to `Off`.
+
+- **Default value**: `50`
+- **Possible values**: any positive integer that is less than or equal to the value specified for [`max_width`](#max_width)
+- **Stable**: Yes
+
+By default this option is set as a percentage of [`max_width`](#max_width) provided by [`use_small_heuristics`](#use_small_heuristics), but a value set directly for `single_line_if_else_max_width` will take precedence.
+
+See also [`max_width`](#max_width) and [`use_small_heuristics`](#use_small_heuristics)
## `space_after_colon`
- **Default value**: `true`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3366)
+- **Stable**: No (tracking issue: [#3366](https://github.com/rust-lang/rustfmt/issues/3366))
#### `true` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3365)
+- **Stable**: No (tracking issue: [#3365](https://github.com/rust-lang/rustfmt/issues/3365))
#### `false` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3367)
+- **Stable**: No (tracking issue: [#3367](https://github.com/rust-lang/rustfmt/issues/3367))
#### `false` (default):
- **Default value** : 0
- **Possible values**: any non-negative integer
-- **Stable**: No (tracking issue: #3371)
+- **Stable**: No (tracking issue: [#3371](https://github.com/rust-lang/rustfmt/issues/3371))
#### `0` (default):
- **Default value**: `true`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3357)
+- **Stable**: No (tracking issue: [#3357](https://github.com/rust-lang/rustfmt/issues/3357))
#### `true` (default):
See also: [`indent_style`](#indent_style).
+## `struct_lit_width`
+
+Maximum width in the body of a struct literal before falling back to vertical formatting. A value of `0` (zero) results in struct literals always being broken into multiple lines. Note this occurs when `use_small_heuristics` is set to `Off`.
+
+- **Default value**: `18`
+- **Possible values**: any positive integer that is less than or equal to the value specified for [`max_width`](#max_width)
+- **Stable**: Yes
+
+By default this option is set as a percentage of [`max_width`](#max_width) provided by [`use_small_heuristics`](#use_small_heuristics), but a value set directly for `struct_lit_width` will take precedence.
+
+See also [`max_width`](#max_width), [`use_small_heuristics`](#use_small_heuristics), and [`struct_lit_single_line`](#struct_lit_single_line)
+
+## `struct_variant_width`
+
+Maximum width in the body of a struct variant before falling back to vertical formatting. A value of `0` (zero) results in struct literals always being broken into multiple lines. Note this occurs when `use_small_heuristics` is set to `Off`.
+
+- **Default value**: `35`
+- **Possible values**: any positive integer that is less than or equal to the value specified for [`max_width`](#max_width)
+- **Stable**: Yes
+
+By default this option is set as a percentage of [`max_width`](#max_width) provided by [`use_small_heuristics`](#use_small_heuristics), but a value set directly for `struct_variant_width` will take precedence.
+
+See also [`max_width`](#max_width) and [`use_small_heuristics`](#use_small_heuristics)
## `tab_spaces`
- **Default value**: `"Vertical"`
- **Possible values**: `"Always"`, `"Never"`, `"Vertical"`
-- **Stable**: No (tracking issue: #3379)
+- **Stable**: No (tracking issue: [#3379](https://github.com/rust-lang/rustfmt/issues/3379))
#### `"Vertical"` (default):
- **Default value**: `true`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3378)
+- **Stable**: No (tracking issue: [#3378](https://github.com/rust-lang/rustfmt/issues/3378))
#### `true` (default):
```rust
- **Default value**: `"Wide"`
- **Possible values**: `"Compressed"`, `"Wide"`
-- **Stable**: No (tracking issue: #3364)
+- **Stable**: No (tracking issue: [#3364](https://github.com/rust-lang/rustfmt/issues/3364))
#### `"Wide"` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3387)
+- **Stable**: No (tracking issue: [#3387](https://github.com/rust-lang/rustfmt/issues/3387))
## `use_field_init_shorthand`
let x = 1;
let y = 2;
let z = 3;
- let a = Foo { x: x, y: y, z: z };
+ let a = Foo { x, y, z };
+ let b = Foo { x: x, y: y, z: z };
}
```
## `use_small_heuristics`
-Whether to use different formatting for items and expressions if they satisfy a heuristic notion of 'small'.
+This option can be used to simplify the management and bulk updates of the granular width configuration settings ([`fn_call_width`](#fn_call_width), [`attr_fn_like_width`](#attr_fn_like_width), [`struct_lit_width`](#struct_lit_width), [`struct_variant_width`](#struct_variant_width), [`array_width`](#array_width), [`chain_width`](#chain_width), [`single_line_if_else_max_width`](#single_line_if_else_max_width)), that respectively control when formatted constructs are multi-lined/vertical based on width.
+
+Note that explicitly provided values for the width configuration settings take precedence and override the calculated values determined by `use_small_heuristics`.
- **Default value**: `"Default"`
- **Possible values**: `"Default"`, `"Off"`, `"Max"`
- **Stable**: Yes
#### `Default` (default):
+When `use_small_heuristics` is set to `Default`, the values for the granular width settings are calculated as a ratio of the value for `max_width`.
+
+The ratios are:
+* [`fn_call_width`](#fn_call_width) - `60%`
+* [`attr_fn_like_width`](#attr_fn_like_width) - `70%`
+* [`struct_lit_width`](#struct_lit_width) - `18%`
+* [`struct_variant_width`](#struct_variant_width) - `35%`
+* [`array_width`](#array_width) - `60%`
+* [`chain_width`](#chain_width) - `60%`
+* [`single_line_if_else_max_width`](#single_line_if_else_max_width) - `50%`
+
+For example when `max_width` is set to `100`, the width settings are:
+* `fn_call_width=60`
+* `attr_fn_like_width=70`
+* `struct_lit_width=18`
+* `struct_variant_width=35`
+* `array_width=60`
+* `chain_width=60`
+* `single_line_if_else_max_width=50`
+
+and when `max_width` is set to `200`:
+* `fn_call_width=120`
+* `attr_fn_like_width=140`
+* `struct_lit_width=36`
+* `struct_variant_width=70`
+* `array_width=120`
+* `chain_width=120`
+* `single_line_if_else_max_width=100`
```rust
enum Lorem {
```
#### `Off`:
+When `use_small_heuristics` is set to `Off`, the granular width settings are functionally disabled and ignored. See the documentation for the respective width config options for specifics.
```rust
enum Lorem {
```
#### `Max`:
+When `use_small_heuristics` is set to `Max`, then each granular width setting is set to the same value as `max_width`.
+
+So if `max_width` is set to `200`, then all the width settings are also set to `200`.
+* `fn_call_width=200`
+* `attr_fn_like_width=200`
+* `struct_lit_width=200`
+* `struct_variant_width=200`
+* `array_width=200`
+* `chain_width=200`
+* `single_line_if_else_max_width=200`
```rust
enum Lorem {
}
```
+
+See also:
+* [`max_width`](#max_width)
+* [`fn_call_width`](#fn_call_width)
+* [`attr_fn_like_width`](#attr_fn_like_width)
+* [`struct_lit_width`](#struct_lit_width)
+* [`struct_variant_width`](#struct_variant_width)
+* [`array_width`](#array_width)
+* [`chain_width`](#chain_width)
+* [`single_line_if_else_max_width`](#single_line_if_else_max_width)
+
## `use_try_shorthand`
Replace uses of the try! macro by the ? shorthand
```rust
fn main() {
+ let lorem = ipsum.map(|dolor| dolor.sit())?;
+
let lorem = try!(ipsum.map(|dolor| dolor.sit()));
}
```
- **Default value**: `One`
- **Possible values**: `One`, `Two`
-- **Stable**: No (tracking issue: #3383)
+- **Stable**: No (tracking issue: [#3383](https://github.com/rust-lang/rustfmt/issues/3383))
### Example
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3359)
+- **Stable**: No (tracking issue: [#3359](https://github.com/rust-lang/rustfmt/issues/3359))
#### `false` (default):
- **Default value**: `false`
- **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3347)
+- **Stable**: No (tracking issue: [#3347](https://github.com/rust-lang/rustfmt/issues/3347))
#### `false` (default):
```rust
+// Lorem ipsum dolor sit amet, consectetur adipiscing elit,
+// sed do eiusmod tempor incididunt ut labore et dolore
+// magna aliqua. Ut enim ad minim veniam, quis nostrud
+// exercitation ullamco laboris nisi ut aliquip ex ea
+// commodo consequat.
+
// Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
```
projects / rust.git / blobdiff