doc: add configuration snippets for match_arm_wrapping options

Author: ashvin021

Configurations.md

@@ -1604,6 +1604,185 @@ fn foo() {
 }
 ```
 
+## `match_arm_wrapping`
+
+Controls when to block wrap match arm bodies.
+
+- **Default value**: `"Default"`
+- **Possible values**: `"Default"`, `"FitFirstLine"`, `"FitEntireBody"`, `"Always"`, `"Preserve`
+- **Stable**: No (tracking issue: #4896)
+
+### Example
+
+#### Original code
+
+```rust
+#![rustfmt::skip]
+
+fn main() {
+ match lorem {
+ 1000 => foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x),
+ 2000 => {
+ println!("{}", sit)
+ }
+ 3000 => panic!(),
+ 4000 => {
+ ()
+ }
+ 5000 => this.a_very_long_function_name(foo, bar, bazz, fizz, another_argument, some_more_arguments, which_dont_fit),
+ }
+}
+```
+
+#### `"Default"` (default):
+
+The default block wrapping settings, as described in the Style Guide.
+
+```rust
+fn main() {
+ match lorem {
+ 1000 => {
+ foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x)
+ }
+ 2000 => {
+ println!("{}", sit)
+ }
+ 3000 => panic!(),
+ 4000 => (),
+ 5000 => this.a_very_long_function_name(
+ foo,
+ bar,
+ bazz,
+ fizz,
+ another_argument,
+ some_more_arguments,
+ which_dont_fit,
+ ),
+ }
+}
+```
+
+#### `"FitFirstLine"`:
+
+Same as the default, except don't block wrap match arms when the opening line of its body can't fit on the same line as the `=>`.
+
+```rust
+fn main() {
+ match lorem {
+ 1000 =>
+ foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x),
+ 2000 => {
+ println!("{}", sit)
+ }
+ 3000 => panic!(),
+ 4000 => (),
+ 5000 => this.a_very_long_function_name(
+ foo,
+ bar,
+ bazz,
+ fizz,
+ another_argument,
+ some_more_arguments,
+ which_dont_fit,
+ ),
+ }
+}
+```
+
+#### `"Always"`:
+
+Always block wrap match arm bodies.
+
+```rust
+fn main() {
+ match lorem {
+ 1000 => {
+ foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x)
+ }
+ 2000 => {
+ println!("{}", sit)
+ }
+ 3000 => {
+ panic!()
+ }
+ 4000 => {
+ ()
+ }
+ 5000 => {
+ this.a_very_long_function_name(
+ foo,
+ bar,
+ bazz,
+ fizz,
+ another_argument,
+ some_more_arguments,
+ which_dont_fit,
+ )
+ }
+ }
+}
+```
+
+#### `"Preserve"`:
+
+Preserve block wrapping on match arm bodies if the developer originally had the body wrapped.
+
+```rust
+fn main() {
+ match lorem {
+ 1000 => {
+ foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x)
+ }
+ 2000 => {
+ println!("{}", sit)
+ }
+ 3000 => panic!(),
+ 4000 => {
+ ()
+ }
+ 5000 => this.a_very_long_function_name(
+ foo,
+ bar,
+ bazz,
+ fizz,
+ another_argument,
+ some_more_arguments,
+ which_dont_fit,
+ ),
+ }
+}
+```
+
+#### `"FitEntireBody"`:
+
+Same as default, except block wrap the match arm if the entire body cannot fit on the same line as the `=>`.
+
+```rust
+fn main() {
+ match lorem {
+ 1000 => {
+ foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(x)
+ }
+ 2000 => {
+ println!("{}", sit)
+ }
+ 3000 => panic!(),
+ 4000 => (),
+ 5000 => {
+ this.a_very_long_function_name(
+ foo,
+ bar,
+ bazz,
+ fizz,
+ another_argument,
+ some_more_arguments,
+ which_dont_fit,
+ )
+ }
+ }
+}
+```
+
 ## `match_block_trailing_comma`
 
 Put a trailing comma after a block based match arm (non-block arms are not affected)