Fix new lines into empty implementation

swayfmt/src/comments.rs

@@ -35,6 +35,18 @@ impl CommentsContext {
     }
 }
 
+#[inline]
+pub fn has_comments_in_formatter(formatter: &Formatter, range: &Range<usize>) -> bool {
+    formatter
+        .comments_context
+        .map
+        .comments_between(range)
+        .peekable()
+        .peek()
+        .is_some()
+}
+
+#[inline]
 pub fn has_comments<I: Iterator>(comments: I) -> bool {
     comments.peekable().peek().is_some()
 }

swayfmt/src/items/item_fn/mod.rs

@@ -1,5 +1,5 @@
 use crate::{
-    comments::{rewrite_with_comments, write_comments},
+    comments::{has_comments_in_formatter, rewrite_with_comments, write_comments},
     config::items::ItemBraceStyle,
     formatter::{
         shape::{ExprKind, LineStyle},
@@ -51,11 +51,11 @@ impl Format for ItemFn {
 
                     Self::close_curly_brace(formatted_code, formatter)?;
                 } else {
+                    let range = self.span().into();
                     Self::open_curly_brace(formatted_code, formatter)?;
-                    formatter.indent();
-                    let comments = write_comments(formatted_code, self.span().into(), formatter)?;
-                    if !comments {
-                        formatter.unindent();
+                    if has_comments_in_formatter(formatter, &range) {
+                        formatter.indent();
+                        write_comments(formatted_code, range, formatter)?;
                     }
                     Self::close_curly_brace(formatted_code, formatter)?;
                 }

swayfmt/src/items/item_impl/mod.rs

@@ -1,5 +1,5 @@
 use crate::{
-    comments::rewrite_with_comments,
+    comments::{has_comments_in_formatter, rewrite_with_comments, write_comments},
     config::items::ItemBraceStyle,
     formatter::*,
     utils::{
@@ -38,14 +38,27 @@ impl Format for ItemImpl {
             where_clause.format(formatted_code, formatter)?;
             formatter.shape.code_line.update_where_clause(true);
         }
-        Self::open_curly_brace(formatted_code, formatter)?;
+
         let contents = self.contents.get();
-        for item in contents.iter() {
-            write!(formatted_code, "{}", formatter.indent_to_str()?,)?;
-            item.format(formatted_code, formatter)?;
+        if contents.is_empty() {
+            let range = self.span().into();
+            Self::open_curly_brace(formatted_code, formatter)?;
+            if has_comments_in_formatter(formatter, &range) {
+                formatter.indent();
+                write_comments(formatted_code, range, formatter)?;
+            }
+            Self::close_curly_brace(formatted_code, formatter)?;
+        } else {
+            Self::open_curly_brace(formatted_code, formatter)?;
+            formatter.indent();
             writeln!(formatted_code)?;
+            for item in contents.iter() {
+                write!(formatted_code, "{}", formatter.indent_to_str()?,)?;
+                item.format(formatted_code, formatter)?;
+                writeln!(formatted_code)?;
+            }
+            Self::close_curly_brace(formatted_code, formatter)?;
         }
-        Self::close_curly_brace(formatted_code, formatter)?;
 
         rewrite_with_comments::<ItemImpl>(
             formatter,
@@ -79,7 +92,6 @@ impl CurlyBrace for ItemImpl {
         formatter: &mut Formatter,
     ) -> Result<(), FormatterError> {
         let brace_style = formatter.config.items.item_brace_style;
-        formatter.indent();
         let open_brace = Delimiter::Brace.as_open_char();
         match brace_style {
             ItemBraceStyle::AlwaysNextLine => {
@@ -88,11 +100,11 @@ impl CurlyBrace for ItemImpl {
             }
             ItemBraceStyle::SameLineWhere => match formatter.shape.code_line.has_where_clause {
                 true => {
-                    writeln!(line, "{open_brace}")?;
+                    write!(line, "{open_brace}")?;
                     formatter.shape.code_line.update_where_clause(false);
                 }
                 false => {
-                    writeln!(line, " {open_brace}")?;
+                    write!(line, " {open_brace}")?;
                 }
             },
             _ => {

swayfmt/tests/mod.rs

@@ -1702,3 +1702,17 @@ pub enum Input {
 "#,
     );
 }
+
+#[test]
+fn empty_impl() {
+    check(
+        r#"
+library;
+impl OrdEq for u256 {
+}
+        "#,
+        r#"library;
+impl OrdEq for u256 {}
+"#,
+    );
+}