Deprecate and Rename fn_args_layout -> fn_params_layout

fn_args_layout is now deprecated.

This option was renamed to better communicate that it affects the layout
of parameters in function signatures and not the layout of arguments in
function calls.

Because the `fn_args_layout` is a stable option the renamed option is
also stable, however users who set `fn_args_layout` will get a warning
message letting them know that the option has been renamed.

Author: ytmimi

Configurations.md

@@ -645,7 +645,8 @@ trailing whitespaces.
 
 ## `fn_args_layout`
 
-Control the layout of arguments in a function
+This option is deprecated and has been renamed to `fn_params_layout` to better communicate that
+it affects the layout of parameters in function signatures.
 
 - **Default value**: `"Tall"`
 - **Possible values**: `"Compressed"`, `"Tall"`, `"Vertical"`
@@ -753,6 +754,8 @@ trait Lorem {
 }
 ```
 
+See also [`fn_params_layout`](#fn_params_layout)
+
 ## `fn_call_width`
 
 Maximum width of the args of a function call before falling back to vertical formatting.
@@ -765,6 +768,117 @@ By default this option is set as a percentage of [`max_width`](#max_width) provi
 
 See also [`max_width`](#max_width) and [`use_small_heuristics`](#use_small_heuristics)
 
+## `fn_params_layout`
+
+Control the layout of parameters in function signatures.
+
+- **Default value**: `"Tall"`
+- **Possible values**: `"Compressed"`, `"Tall"`, `"Vertical"`
+- **Stable**: Yes
+
+#### `"Tall"` (default):
+
+```rust
+trait Lorem {
+    fn lorem(ipsum: Ipsum, dolor: Dolor, sit: Sit, amet: Amet);
+
+    fn lorem(ipsum: Ipsum, dolor: Dolor, sit: Sit, amet: Amet) {
+        // body
+    }
+
+    fn lorem(
+        ipsum: Ipsum,
+        dolor: Dolor,
+        sit: Sit,
+        amet: Amet,
+        consectetur: Consectetur,
+        adipiscing: Adipiscing,
+        elit: Elit,
+    );
+
+    fn lorem(
+        ipsum: Ipsum,
+        dolor: Dolor,
+        sit: Sit,
+        amet: Amet,
+        consectetur: Consectetur,
+        adipiscing: Adipiscing,
+        elit: Elit,
+    ) {
+        // body
+    }
+}
+```
+
+#### `"Compressed"`:
+
+```rust
+trait Lorem {
+    fn lorem(ipsum: Ipsum, dolor: Dolor, sit: Sit, amet: Amet);
+
+    fn lorem(ipsum: Ipsum, dolor: Dolor, sit: Sit, amet: Amet) {
+        // body
+    }
+
+    fn lorem(
+        ipsum: Ipsum, dolor: Dolor, sit: Sit, amet: Amet, consectetur: Consectetur,
+        adipiscing: Adipiscing, elit: Elit,
+    );
+
+    fn lorem(
+        ipsum: Ipsum, dolor: Dolor, sit: Sit, amet: Amet, consectetur: Consectetur,
+        adipiscing: Adipiscing, elit: Elit,
+    ) {
+        // body
+    }
+}
+```
+
+#### `"Vertical"`:
+
+```rust
+trait Lorem {
+    fn lorem(
+        ipsum: Ipsum,
+        dolor: Dolor,
+        sit: Sit,
+        amet: Amet,
+    );
+
+    fn lorem(
+        ipsum: Ipsum,
+        dolor: Dolor,
+        sit: Sit,
+        amet: Amet,
+    ) {
+        // body
+    }
+
+    fn lorem(
+        ipsum: Ipsum,
+        dolor: Dolor,
+        sit: Sit,
+        amet: Amet,
+        consectetur: Consectetur,
+        adipiscing: Adipiscing,
+        elit: Elit,
+    );
+
+    fn lorem(
+        ipsum: Ipsum,
+        dolor: Dolor,
+        sit: Sit,
+        amet: Amet,
+        consectetur: Consectetur,
+        adipiscing: Adipiscing,
+        elit: Elit,
+    ) {
+        // body
+    }
+}
+```
+
+
 ## `fn_single_line`
 
 Put single-expression functions on a single line

src/config/config_type.rs

@@ -127,6 +127,7 @@ macro_rules! create_config {
                     | "array_width"
                     | "chain_width" => self.0.set_heuristics(),
                     "merge_imports" => self.0.set_merge_imports(),
+                    "fn_args_layout" => self.0.set_fn_args_layout(),
                     &_ => (),
                 }
             }
@@ -181,6 +182,7 @@ macro_rules! create_config {
                 self.set_heuristics();
                 self.set_ignore(dir);
                 self.set_merge_imports();
+                self.set_fn_args_layout();
                 self
             }
 
@@ -273,14 +275,21 @@ macro_rules! create_config {
                     | "array_width"
                     | "chain_width" => self.set_heuristics(),
                     "merge_imports" => self.set_merge_imports(),
+                    "fn_args_layout" => self.set_fn_args_layout(),
                     &_ => (),
                 }
             }
 
             #[allow(unreachable_pub)]
             pub fn is_hidden_option(name: &str) -> bool {
-                const HIDE_OPTIONS: [&str; 5] =
-                    ["verbose", "verbose_diff", "file_lines", "width_heuristics", "merge_imports"];
+                const HIDE_OPTIONS: [&str; 6] = [
+                    "verbose",
+                    "verbose_diff",
+                    "file_lines",
+                    "width_heuristics",
+                    "merge_imports",
+                    "fn_args_layout"
+                ];
                 HIDE_OPTIONS.contains(&name)
             }
 
@@ -430,6 +439,18 @@ macro_rules! create_config {
                 }
             }
 
+            fn set_fn_args_layout(&mut self) {
+                if self.was_set().fn_args_layout() {
+                    eprintln!(
+                        "Warning: the `fn_args_layout` option is deprecated. \
+                        Use `fn_params_layout`. instead"
+                    );
+                    if !self.was_set().fn_params_layout() {
+                        self.fn_params_layout.2 = self.fn_args_layout();
+                    }
+                }
+            }
+
             #[allow(unreachable_pub)]
             /// Returns `true` if the config key was explicitly set and is the default value.
             pub fn is_default(&self, key: &str) -> bool {

src/config/mod.rs

@@ -124,7 +124,9 @@ create_config! {
     force_multiline_blocks: bool, false, false,
         "Force multiline closure bodies and match arms to be wrapped in a block";
     fn_args_layout: Density, Density::Tall, true,
-        "Control the layout of arguments in a function";
+        "(deprecated: use fn_params_layout instead)";
+    fn_params_layout: Density, Density::Tall, true,
+        "Control the layout of parameters in function signatures.";
     brace_style: BraceStyle, BraceStyle::SameLineWhere, false, "Brace style for items";
     control_brace_style: ControlBraceStyle, ControlBraceStyle::AlwaysSameLine, false,
         "Brace style for control flow constructs";
@@ -196,6 +198,7 @@ impl PartialConfig {
         cloned.width_heuristics = None;
         cloned.print_misformatted_file_names = None;
         cloned.merge_imports = None;
+        cloned.fn_args_layout = None;
 
         ::toml::to_string(&cloned).map_err(ToTomlError)
     }
@@ -442,6 +445,12 @@ mod test {
                 "Merge imports";
             merge_imports: bool, false, false, "(deprecated: use imports_granularity instead)";
 
+            // fn_args_layout renamed to fn_params_layout
+            fn_args_layout: Density, Density::Tall, true,
+                "(deprecated: use fn_params_layout instead)";
+            fn_params_layout: Density, Density::Tall, true,
+                "Control the layout of parameters in a function signatures.";
+
             // Width Heuristics
             use_small_heuristics: Heuristics, Heuristics::Default, true,
                 "Whether to use different formatting for items and \
@@ -644,7 +653,7 @@ enum_discrim_align_threshold = 0
 match_arm_blocks = true
 match_arm_leading_pipes = "Never"
 force_multiline_blocks = false
-fn_args_layout = "Tall"
+fn_params_layout = "Tall"
 brace_style = "SameLineWhere"
 control_brace_style = "AlwaysSameLine"
 trailing_semicolon = true

src/items.rs

@@ -2602,7 +2602,7 @@ fn rewrite_params(
         &param_items,
         context
             .config
-            .fn_args_layout()
+            .fn_params_layout()
             .to_list_tactic(param_items.len()),
         Separator::Comma,
         one_line_budget,

tests/config/small_tabs.toml

@@ -3,7 +3,7 @@ comment_width = 80
 tab_spaces = 2
 newline_style = "Unix"
 brace_style = "SameLineWhere"
-fn_args_layout = "Tall"
+fn_params_layout = "Tall"
 trailing_comma = "Vertical"
 indent_style = "Block"
 reorder_imports = false

tests/source/configs/fn_args_layout/compressed.rs renamed to tests/source/configs/fn_params_layout/compressed.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Compressed
+// rustfmt-fn_params_layout: Compressed
 // Function arguments density
 
 trait Lorem {

tests/source/configs/fn_args_layout/tall.rs renamed to tests/source/configs/fn_params_layout/tall.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Tall
+// rustfmt-fn_params_layout: Tall
 // Function arguments density
 
 trait Lorem {

tests/source/configs/fn_args_layout/vertical.rs renamed to tests/source/configs/fn_params_layout/vertical.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Vertical
+// rustfmt-fn_params_layout: Vertical
 // Function arguments density
 
 trait Lorem {

tests/source/fn-custom-7.rs

@@ -1,5 +1,5 @@
 // rustfmt-normalize_comments: true
-// rustfmt-fn_args_layout: Vertical
+// rustfmt-fn_params_layout: Vertical
 // rustfmt-brace_style: AlwaysNextLine
 
 // Case with only one variable.

tests/source/fn-custom.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Compressed
+// rustfmt-fn_params_layout: Compressed
 // Test some of the ways function signatures can be customised.
 
 // Test compressed layout of args.

tests/source/fn_args_layout-vertical.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Vertical
+// rustfmt-fn_params_layout: Vertical
 
 // Empty list should stay on one line.
 fn do_bar(

tests/target/configs/fn_args_layout/compressed.rs renamed to tests/target/configs/fn_params_layout/compressed.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Compressed
+// rustfmt-fn_params_layout: Compressed
 // Function arguments density
 
 trait Lorem {

tests/target/configs/fn_args_layout/tall.rs renamed to tests/target/configs/fn_params_layout/tall.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Tall
+// rustfmt-fn_params_layout: Tall
 // Function arguments density
 
 trait Lorem {

tests/target/configs/fn_args_layout/vertical.rs renamed to tests/target/configs/fn_params_layout/vertical.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Vertical
+// rustfmt-fn_params_layout: Vertical
 // Function arguments density
 
 trait Lorem {

tests/target/fn-custom-7.rs

@@ -1,5 +1,5 @@
 // rustfmt-normalize_comments: true
-// rustfmt-fn_args_layout: Vertical
+// rustfmt-fn_params_layout: Vertical
 // rustfmt-brace_style: AlwaysNextLine
 
 // Case with only one variable.

tests/target/fn-custom.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Compressed
+// rustfmt-fn_params_layout: Compressed
 // Test some of the ways function signatures can be customised.
 
 // Test compressed layout of args.

tests/target/fn_args_layout-vertical.rs

@@ -1,4 +1,4 @@
-// rustfmt-fn_args_layout: Vertical
+// rustfmt-fn_params_layout: Vertical
 
 // Empty list should stay on one line.
 fn do_bar() -> u8 {

tests/target/issue-4791/issue_4928.rs

@@ -1,7 +1,7 @@
 // rustfmt-brace_style: SameLineWhere
 // rustfmt-comment_width: 100
 // rustfmt-edition: 2018
-// rustfmt-fn_args_layout: Compressed
+// rustfmt-fn_params_layout: Compressed
 // rustfmt-hard_tabs: false
 // rustfmt-match_block_trailing_comma: true
 // rustfmt-max_width: 100