fix clippy::needless_borrow

src/attr.rs

@@ -451,7 +451,7 @@ impl Rewrite for [ast::Attribute] {
                         if next.is_doc_comment() {
                             let snippet = context.snippet(missing_span);
                             let (_, mlb) = has_newlines_before_after_comment(snippet);
-                            result.push_str(&mlb);
+                            result.push_str(mlb);
                         }
                     }
                     result.push('\n');
@@ -484,7 +484,7 @@ impl Rewrite for [ast::Attribute] {
                     if next.is_doc_comment() {
                         let snippet = context.snippet(missing_span);
                         let (_, mlb) = has_newlines_before_after_comment(snippet);
-                        result.push_str(&mlb);
+                        result.push_str(mlb);
                     }
                 }
                 result.push('\n');

src/attr/doc_comment.rs

@@ -77,7 +77,7 @@ mod tests {
     ) {
         assert_eq!(
             expected_comment,
-            format!("{}", DocCommentFormatter::new(&literal, style))
+            format!("{}", DocCommentFormatter::new(literal, style))
         );
     }
 }

src/cargo-fmt/main.rs

@@ -401,12 +401,12 @@ fn get_targets_root_only(
 
 fn get_targets_recursive(
     manifest_path: Option<&Path>,
-    mut targets: &mut BTreeSet<Target>,
+    targets: &mut BTreeSet<Target>,
     visited: &mut BTreeSet<String>,
 ) -> Result<(), io::Error> {
     let metadata = get_cargo_metadata(manifest_path)?;
     for package in &metadata.packages {
-        add_targets(&package.targets, &mut targets);
+        add_targets(&package.targets, targets);
 
         // Look for local dependencies using information available since cargo v1.51
         // It's theoretically possible someone could use a newer version of rustfmt with
@@ -427,7 +427,7 @@ fn get_targets_recursive(
                     .any(|p| p.manifest_path.eq(&manifest_path))
             {
                 visited.insert(dependency.name.to_owned());
-                get_targets_recursive(Some(&manifest_path), &mut targets, visited)?;
+                get_targets_recursive(Some(&manifest_path), targets, visited)?;
             }
         }
     }

src/chains.rs

@@ -568,7 +568,7 @@ impl<'a> ChainFormatterShared<'a> {
         } else {
             self.rewrites
                 .iter()
-                .map(|rw| utils::unicode_str_width(&rw))
+                .map(|rw| utils::unicode_str_width(rw))
                 .sum()
         } + last.tries;
         let one_line_budget = if self.child_count == 1 {
@@ -673,7 +673,7 @@ impl<'a> ChainFormatterShared<'a> {
                 ChainItemKind::Comment(_, CommentPosition::Top) => result.push_str(&connector),
                 _ => result.push_str(&connector),
             }
-            result.push_str(&rewrite);
+            result.push_str(rewrite);
         }
 
         Some(result)

src/comment.rs

@@ -563,7 +563,7 @@ impl<'a> CommentRewrite<'a> {
             result.push_str(line);
             result.push_str(match iter.peek() {
                 Some(next_line) if next_line.is_empty() => sep.trim_end(),
-                Some(..) => &sep,
+                Some(..) => sep,
                 None => "",
             });
         }
@@ -622,7 +622,7 @@ impl<'a> CommentRewrite<'a> {
         let is_last = i == count_newlines(orig);
 
         if let Some(ref mut ib) = self.item_block {
-            if ib.add_line(&line) {
+            if ib.add_line(line) {
                 return false;
             }
             self.is_prev_line_multi_line = false;
@@ -684,8 +684,8 @@ impl<'a> CommentRewrite<'a> {
         self.item_block = None;
         if let Some(stripped) = line.strip_prefix("```") {
             self.code_block_attr = Some(CodeBlockAttribute::new(stripped))
-        } else if self.fmt.config.wrap_comments() && ItemizedBlock::is_itemized_line(&line) {
-            let ib = ItemizedBlock::new(&line);
+        } else if self.fmt.config.wrap_comments() && ItemizedBlock::is_itemized_line(line) {
+            let ib = ItemizedBlock::new(line);
             self.item_block = Some(ib);
             return false;
         }
@@ -941,7 +941,7 @@ fn left_trim_comment_line<'a>(line: &'a str, style: &CommentStyle<'_>) -> (&'a s
     {
         (&line[4..], true)
     } else if let CommentStyle::Custom(opener) = *style {
-        if let Some(ref stripped) = line.strip_prefix(opener) {
+        if let Some(stripped) = line.strip_prefix(opener) {
             (stripped, true)
         } else {
             (&line[opener.trim_end().len()..], false)
@@ -1570,7 +1570,7 @@ pub(crate) fn recover_comment_removed(
                 context.parse_sess.span_to_filename(span),
                 vec![FormattingError::from_span(
                     span,
-                    &context.parse_sess,
+                    context.parse_sess,
                     ErrorKind::LostComment,
                 )],
             );
@@ -1675,7 +1675,7 @@ impl<'a> Iterator for CommentReducer<'a> {
 fn remove_comment_header(comment: &str) -> &str {
     if comment.starts_with("///") || comment.starts_with("//!") {
         &comment[3..]
-    } else if let Some(ref stripped) = comment.strip_prefix("//") {
+    } else if let Some(stripped) = comment.strip_prefix("//") {
         stripped
     } else if (comment.starts_with("/**") && !comment.starts_with("/**/"))
         || comment.starts_with("/*!")

src/emitter/checkstyle.rs

@@ -121,15 +121,15 @@ mod tests {
             format!(r#"<file name="{}">"#, bin_file),
             format!(
                 r#"<error line="2" severity="warning" message="Should be `{}`" />"#,
-                XmlEscaped(&r#"    println!("Hello, world!");"#),
+                XmlEscaped(r#"    println!("Hello, world!");"#),
             ),
             String::from("</file>"),
         ];
         let exp_lib_xml = vec![
             format!(r#"<file name="{}">"#, lib_file),
             format!(
                 r#"<error line="2" severity="warning" message="Should be `{}`" />"#,
-                XmlEscaped(&r#"    println!("Greetings!");"#),
+                XmlEscaped(r#"    println!("Greetings!");"#),
             ),
             String::from("</file>"),
         ];

src/emitter/diff.rs

@@ -23,7 +23,7 @@ impl Emitter for DiffEmitter {
         }: FormattedFile<'_>,
     ) -> Result<EmitterResult, io::Error> {
         const CONTEXT_SIZE: usize = 3;
-        let mismatch = make_diff(&original_text, formatted_text, CONTEXT_SIZE);
+        let mismatch = make_diff(original_text, formatted_text, CONTEXT_SIZE);
         let has_diff = !mismatch.is_empty();
 
         if has_diff {

src/expr.rs

@@ -257,7 +257,7 @@ pub(crate) fn format_expr(
                         }
                         _ => false,
                     },
-                    ast::ExprKind::Unary(_, ref expr) => needs_space_before_range(context, &expr),
+                    ast::ExprKind::Unary(_, ref expr) => needs_space_before_range(context, expr),
                     _ => false,
                 }
             }
@@ -423,7 +423,7 @@ fn rewrite_empty_block(
     prefix: &str,
     shape: Shape,
 ) -> Option<String> {
-    if block_has_statements(&block) {
+    if block_has_statements(block) {
         return None;
     }
 
@@ -1148,7 +1148,7 @@ pub(crate) fn is_empty_block(
     block: &ast::Block,
     attrs: Option<&[ast::Attribute]>,
 ) -> bool {
-    !block_has_statements(&block)
+    !block_has_statements(block)
         && !block_contains_comment(context, block)
         && attrs.map_or(true, |a| inner_attributes(a).is_empty())
 }
@@ -1621,7 +1621,7 @@ fn rewrite_struct_lit<'a>(
     };
 
     let fields_str =
-        wrap_struct_field(context, &attrs, &fields_str, shape, v_shape, one_line_width)?;
+        wrap_struct_field(context, attrs, &fields_str, shape, v_shape, one_line_width)?;
     Some(format!("{} {{{}}}", path_str, fields_str))
 
     // FIXME if context.config.indent_style() == Visual, but we run out
@@ -1888,7 +1888,7 @@ pub(crate) fn rewrite_assign_rhs_expr<R: Rewrite>(
     shape: Shape,
     rhs_tactics: RhsTactics,
 ) -> Option<String> {
-    let last_line_width = last_line_width(&lhs).saturating_sub(if lhs.contains('\n') {
+    let last_line_width = last_line_width(lhs).saturating_sub(if lhs.contains('\n') {
         shape.indent.width()
     } else {
         0
@@ -1947,7 +1947,7 @@ pub(crate) fn rewrite_assign_rhs_with_comments<S: Into<String>, R: Rewrite>(
 
     if contains_comment {
         let rhs = rhs.trim_start();
-        combine_strs_with_missing_comments(context, &lhs, &rhs, between_span, shape, allow_extend)
+        combine_strs_with_missing_comments(context, &lhs, rhs, between_span, shape, allow_extend)
     } else {
         Some(lhs + &rhs)
     }

src/formatting.rs

@@ -155,7 +155,7 @@ impl<'a, T: FormatHandler + 'a> FormatContext<'a, T> {
         let snippet_provider = self.parse_session.snippet_provider(module.span);
         let mut visitor = FmtVisitor::from_parse_sess(
             &self.parse_session,
-            &self.config,
+            self.config,
             &snippet_provider,
             self.report.clone(),
         );
@@ -180,7 +180,7 @@ impl<'a, T: FormatHandler + 'a> FormatContext<'a, T> {
             &mut visitor.buffer,
             &path,
             &visitor.skipped_range.borrow(),
-            &self.config,
+            self.config,
             &self.report,
         );
 

src/imports.rs

@@ -275,7 +275,7 @@ impl UseTree {
         shape: Shape,
     ) -> Option<String> {
         let vis = self.visibility.as_ref().map_or(Cow::from(""), |vis| {
-            crate::utils::format_visibility(context, &vis)
+            crate::utils::format_visibility(context, vis)
         });
         let use_str = self
             .rewrite(context, shape.offset_left(vis.len())?)
@@ -929,7 +929,7 @@ impl Rewrite for UseTree {
     fn rewrite(&self, context: &RewriteContext<'_>, mut shape: Shape) -> Option<String> {
         let mut result = String::with_capacity(256);
         let mut iter = self.path.iter().peekable();
-        while let Some(ref segment) = iter.next() {
+        while let Some(segment) = iter.next() {
             let segment_str = segment.rewrite(context, shape)?;
             result.push_str(&segment_str);
             if iter.peek().is_some() {

src/items.rs

@@ -226,7 +226,7 @@ impl<'a> FnSig<'a> {
     fn to_str(&self, context: &RewriteContext<'_>) -> String {
         let mut result = String::with_capacity(128);
         // Vis defaultness constness unsafety abi.
-        result.push_str(&*format_visibility(context, &self.visibility));
+        result.push_str(&*format_visibility(context, self.visibility));
         result.push_str(format_defaultness(self.defaultness));
         result.push_str(format_constness(self.constness));
         result.push_str(format_async(&self.is_async));
@@ -1220,7 +1220,7 @@ impl<'a> Rewrite for TraitAliasBounds<'a> {
         } else if fits_single_line {
             Cow::from(" ")
         } else {
-            shape.indent.to_string_with_newline(&context.config)
+            shape.indent.to_string_with_newline(context.config)
         };
 
         Some(format!("{}{}{}", generic_bounds_str, space, where_str))
@@ -1238,7 +1238,7 @@ pub(crate) fn format_trait_alias(
     let alias = rewrite_ident(context, ident);
     // 6 = "trait ", 2 = " ="
     let g_shape = shape.offset_left(6)?.sub_width(2)?;
-    let generics_str = rewrite_generics(context, &alias, generics, g_shape)?;
+    let generics_str = rewrite_generics(context, alias, generics, g_shape)?;
     let vis_str = format_visibility(context, vis);
     let lhs = format!("{}trait {} =", vis_str, generics_str);
     // 1 = ";"
@@ -1386,7 +1386,7 @@ fn format_empty_struct_or_tuple(
     closer: &str,
 ) {
     // 3 = " {}" or "();"
-    let used_width = last_line_used_width(&result, offset.width()) + 3;
+    let used_width = last_line_used_width(result, offset.width()) + 3;
     if used_width > context.config.max_width() {
         result.push_str(&offset.to_string_with_newline(context.config))
     }
@@ -2066,7 +2066,7 @@ fn rewrite_explicit_self(
                     )?;
                     Some(combine_strs_with_missing_comments(
                         context,
-                        &param_attrs,
+                        param_attrs,
                         &format!("&{} {}self", lifetime_str, mut_str),
                         span,
                         shape,
@@ -2075,7 +2075,7 @@ fn rewrite_explicit_self(
                 }
                 None => Some(combine_strs_with_missing_comments(
                     context,
-                    &param_attrs,
+                    param_attrs,
                     &format!("&{}self", mut_str),
                     span,
                     shape,
@@ -2091,7 +2091,7 @@ fn rewrite_explicit_self(
 
             Some(combine_strs_with_missing_comments(
                 context,
-                &param_attrs,
+                param_attrs,
                 &format!("{}self: {}", format_mutability(mutability), type_str),
                 span,
                 shape,
@@ -2100,7 +2100,7 @@ fn rewrite_explicit_self(
         }
         ast::SelfKind::Value(mutability) => Some(combine_strs_with_missing_comments(
             context,
-            &param_attrs,
+            param_attrs,
             &format!("{}self", format_mutability(mutability)),
             span,
             shape,
@@ -2226,7 +2226,7 @@ fn rewrite_fn_base(
     }
 
     // Skip `pub(crate)`.
-    let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
+    let lo_after_visibility = get_bytepos_after_visibility(fn_sig.visibility, span);
     // A conservative estimation, the goal is to be over all parens in generics
     let params_start = fn_sig
         .generics
@@ -2984,7 +2984,7 @@ fn format_header(
     let mut result = String::with_capacity(128);
     let shape = Shape::indented(offset, context.config);
 
-    result.push_str(&format_visibility(context, vis).trim());
+    result.push_str(format_visibility(context, vis).trim());
 
     // Check for a missing comment between the visibility and the item name.
     let after_vis = vis.span.hi();
@@ -3005,7 +3005,7 @@ fn format_header(
         }
     }
 
-    result.push_str(&rewrite_ident(context, ident));
+    result.push_str(rewrite_ident(context, ident));
 
     result
 }
@@ -3133,7 +3133,7 @@ impl Rewrite for ast::ForeignItem {
                     let inner_attrs = inner_attributes(&self.attrs);
                     let fn_ctxt = visit::FnCtxt::Foreign;
                     visitor.visit_fn(
-                        visit::FnKind::Fn(fn_ctxt, self.ident, &fn_sig, &self.vis, Some(body)),
+                        visit::FnKind::Fn(fn_ctxt, self.ident, fn_sig, &self.vis, Some(body)),
                         generics,
                         &fn_sig.decl,
                         self.span,
@@ -3146,7 +3146,7 @@ impl Rewrite for ast::ForeignItem {
                         context,
                         shape.indent,
                         self.ident,
-                        &FnSig::from_method_sig(&fn_sig, generics, &self.vis),
+                        &FnSig::from_method_sig(fn_sig, generics, &self.vis),
                         span,
                         FnBraceStyle::None,
                     )
@@ -3171,7 +3171,7 @@ impl Rewrite for ast::ForeignItem {
                 let ast::TyAliasKind(_, ref generics, ref generic_bounds, ref type_default) =
                     **ty_alias_kind;
                 rewrite_type(
-                    &context,
+                    context,
                     shape.indent,
                     self.ident,
                     &self.vis,
@@ -3229,7 +3229,7 @@ fn rewrite_attrs(
     combine_strs_with_missing_comments(
         context,
         &attrs_str,
-        &item_str,
+        item_str,
         missed_span,
         shape,
         allow_extend,

src/lib.rs

@@ -283,7 +283,7 @@ impl FormatReport {
         writeln!(
             t,
             "{}",
-            FormatReportFormatterBuilder::new(&self)
+            FormatReportFormatterBuilder::new(self)
                 .enable_colors(true)
                 .build()
         )?;
@@ -297,7 +297,7 @@ impl FormatReport {
 impl fmt::Display for FormatReport {
     // Prints all the formatting errors.
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-        write!(fmt, "{}", FormatReportFormatterBuilder::new(&self).build())?;
+        write!(fmt, "{}", FormatReportFormatterBuilder::new(self).build())?;
         Ok(())
     }
 }