Merge pull request #2384 from topecongiro/init-shorthand

Use field initialization shorthand if possible

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Added
 
+- Add `use_field_init_shorthand` config option.
 - Add `reorder_modules` configuration option.
 
 ## [0.3.6] 2018-01-18

Configurations.md

@@ -1781,6 +1781,48 @@ fn lorem<Ipsum: Dolor+Sit=Amet>() {
 }
 ```
 
+## `use_field_init_shorthand`
+
+Use field initialize shorthand if possible.
+
+- **Default value**: `false`
+- **Possible values**: `true`, `false`
+- **Stable**: No
+
+#### `false` (default):
+
+```rust
+struct Foo {
+    x: u32,
+    y: u32,
+    z: u32,
+}
+
+fn main() {
+    let x = 1;
+    let y = 2;
+    let z = 3;
+    let a = Foo { x: x, y: y, z: z };
+}
+```
+
+#### `true`:
+
+```rust
+struct Foo {
+    x: u32,
+    y: u32,
+    z: u32,
+}
+
+fn main() {
+    let x = 1;
+    let y = 2;
+    let z = 3;
+    let a = Foo { x, y, z };
+}
+```
+
 ## `use_try_shorthand`
 
 Replace uses of the try! macro by the ? shorthand

src/bin/rustfmt.rs

@@ -453,7 +453,7 @@ fn determine_operation(matches: &Matches) -> FmtResult<Operation> {
 
         return Ok(Operation::Stdin {
             input: buffer,
-            config_path: config_path,
+            config_path,
         });
     }
 
@@ -469,8 +469,8 @@ fn determine_operation(matches: &Matches) -> FmtResult<Operation> {
         .collect();
 
     Ok(Operation::Format {
-        files: files,
-        config_path: config_path,
-        minimal_config_path: minimal_config_path,
+        files,
+        config_path,
+        minimal_config_path,
     })
 }

src/closures.rs

@@ -254,7 +254,7 @@ fn rewrite_closure_fn_decl(
     };
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: SeparatorTactic::Never,
         separator_place: SeparatorPlace::Back,

src/comment.rs

@@ -290,11 +290,11 @@ fn rewrite_comment_inner(
     let mut fmt = StringFormat {
         opener: "",
         closer: "",
-        line_start: line_start,
+        line_start,
         line_end: "",
         shape: Shape::legacy(max_chars, fmt_indent),
         trim_end: true,
-        config: config,
+        config,
     };
 
     let line_breaks = count_newlines(orig.trim_right());
@@ -900,7 +900,7 @@ pub struct CommentCodeSlices<'a> {
 impl<'a> CommentCodeSlices<'a> {
     pub fn new(slice: &'a str) -> CommentCodeSlices<'a> {
         CommentCodeSlices {
-            slice: slice,
+            slice,
             last_slice_kind: CodeCharKind::Comment,
             last_slice_end: 0,
         }
@@ -1024,7 +1024,7 @@ fn new(comment: &'a str) -> CommentReducer<'a> {
         let is_block = comment.starts_with("/*");
         let comment = remove_comment_header(comment);
         CommentReducer {
-            is_block: is_block,
+            is_block,
             at_start_line: false, // There are no supplementary '*' on the first line
             iter: comment.chars(),
         }

src/config.rs

@@ -674,6 +674,7 @@ pub fn get_toml_path(dir: &Path) -> Result<Option<PathBuf>, Error> {
     condense_wildcard_suffixes: bool, false, false, "Replace strings of _ wildcards by a single .. \
                                               in tuple patterns";
     force_explicit_abi: bool, true, true, "Always print the abi for extern items";
+    use_field_init_shorthand: bool, false, false, "Use field initialization shorthand if possible";
 
     // Control options (changes the operation of rustfmt, rather than the formatting)
     write_mode: WriteMode, WriteMode::Overwrite, false,

src/expr.rs

@@ -449,7 +449,7 @@ pub fn rewrite_array<T: Rewrite + Spanned + ToExpr>(
     let ends_with_newline = tactic.ends_with_newline(context.config.indent_style());
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: if trailing_comma {
             SeparatorTactic::Always
@@ -470,7 +470,7 @@ pub fn rewrite_array<T: Rewrite + Spanned + ToExpr>(
         },
         separator_place: SeparatorPlace::Back,
         shape: nested_shape,
-        ends_with_newline: ends_with_newline,
+        ends_with_newline,
         preserve_newline: false,
         config: context.config,
     };
@@ -787,35 +787,35 @@ fn new_if(
     ) -> ControlFlow<'a> {
         ControlFlow {
             cond: Some(cond),
-            block: block,
-            else_block: else_block,
+            block,
+            else_block,
             label: None,
-            pat: pat,
+            pat,
             keyword: "if",
             matcher: match pat {
                 Some(..) => "let",
                 None => "",
             },
             connector: " =",
-            allow_single_line: allow_single_line,
-            nested_if: nested_if,
-            span: span,
+            allow_single_line,
+            nested_if,
+            span,
         }
     }
 
     fn new_loop(block: &'a ast::Block, label: Option<ast::Label>, span: Span) -> ControlFlow<'a> {
         ControlFlow {
             cond: None,
-            block: block,
+            block,
             else_block: None,
-            label: label,
+            label,
             pat: None,
             keyword: "loop",
             matcher: "",
             connector: "",
             allow_single_line: false,
             nested_if: false,
-            span: span,
+            span,
         }
     }
 
@@ -828,10 +828,10 @@ fn new_while(
     ) -> ControlFlow<'a> {
         ControlFlow {
             cond: Some(cond),
-            block: block,
+            block,
             else_block: None,
-            label: label,
-            pat: pat,
+            label,
+            pat,
             keyword: "while",
             matcher: match pat {
                 Some(..) => "let",
@@ -840,7 +840,7 @@ fn new_while(
             connector: " =",
             allow_single_line: false,
             nested_if: false,
-            span: span,
+            span,
         }
     }
 
@@ -853,16 +853,16 @@ fn new_for(
     ) -> ControlFlow<'a> {
         ControlFlow {
             cond: Some(cond),
-            block: block,
+            block,
             else_block: None,
-            label: label,
+            label,
             pat: Some(pat),
             keyword: "for",
             matcher: "",
             connector: " in",
             allow_single_line: false,
             nested_if: false,
-            span: span,
+            span,
         }
     }
 
@@ -1488,7 +1488,7 @@ fn rewrite_match_pattern(
         )
     };
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: " |",
         trailing_separator: SeparatorTactic::Never,
         separator_place: context.config.binop_separator(),
@@ -1992,7 +1992,7 @@ fn rewrite_call_args<'a, T>(
     );
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: if force_trailing_comma {
             SeparatorTactic::Always
@@ -2569,9 +2569,13 @@ pub fn rewrite_field(
     if contains_skip(&field.attrs) {
         return Some(context.snippet(field.span()).to_owned());
     }
-    let name = &field.ident.node.to_string();
+    let mut attrs_str = field.attrs.rewrite(context, shape)?;
+    if !attrs_str.is_empty() {
+        attrs_str.push_str(&format!("\n{}", shape.indent.to_string(context.config)));
+    };
+    let name = field.ident.node.to_string();
     if field.is_shorthand {
-        Some(name.to_string())
+        Some(attrs_str + &name)
     } else {
         let mut separator = String::from(struct_lit_field_separator(context.config));
         for _ in 0..prefix_max_width.checked_sub(name.len()).unwrap_or(0) {
@@ -2581,12 +2585,10 @@ pub fn rewrite_field(
         let expr_shape = shape.offset_left(overhead)?;
         let expr = field.expr.rewrite(context, expr_shape);
 
-        let mut attrs_str = field.attrs.rewrite(context, shape)?;
-        if !attrs_str.is_empty() {
-            attrs_str.push_str(&format!("\n{}", shape.indent.to_string(context.config)));
-        };
-
         match expr {
+            Some(ref e) if e.as_str() == name && context.config.use_field_init_shorthand() => {
+                Some(attrs_str + &name)
+            }
             Some(e) => Some(format!("{}{}{}{}", attrs_str, name, separator, e)),
             None => {
                 let expr_offset = shape.indent.block_indent(context.config);
@@ -2675,11 +2677,11 @@ fn rewrite_tuple_in_visual_indent_style<'a, T>(
         nested_shape.width,
     );
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: SeparatorTactic::Never,
         separator_place: SeparatorPlace::Back,
-        shape: shape,
+        shape,
         ends_with_newline: false,
         preserve_newline: false,
         config: context.config,

src/file_lines.rs

@@ -34,7 +34,7 @@ fn from(range: &'a LineRange) -> Range {
 
 impl Range {
     pub fn new(lo: usize, hi: usize) -> Range {
-        Range { lo: lo, hi: hi }
+        Range { lo, hi }
     }
 
     fn is_empty(self) -> bool {

src/imports.rs

@@ -299,7 +299,7 @@ fn rewrite_imports(
         separator: "",
         trailing_separator: SeparatorTactic::Never,
         separator_place: SeparatorPlace::Back,
-        shape: shape,
+        shape,
         ends_with_newline: true,
         preserve_newline: false,
         config: context.config,
@@ -552,7 +552,7 @@ fn rewrite_nested_use_tree(
         && tactic != DefinitiveListTactic::Horizontal;
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: if ends_with_newline {
             context.config.trailing_comma()
@@ -561,7 +561,7 @@ fn rewrite_nested_use_tree(
         },
         separator_place: SeparatorPlace::Back,
         shape: nested_shape,
-        ends_with_newline: ends_with_newline,
+        ends_with_newline,
         preserve_newline: true,
         config: context.config,
     };

src/issues.rs

@@ -90,8 +90,8 @@ pub fn new(report_todo: ReportTactic, report_fixme: ReportTactic) -> BadIssueSee
                 todo_idx: 0,
                 fixme_idx: 0,
             },
-            report_todo: report_todo,
-            report_fixme: report_fixme,
+            report_todo,
+            report_fixme,
         }
     }
 
@@ -169,8 +169,8 @@ fn inspect_issue(&mut self, c: char, mut todo_idx: usize, mut fixme_idx: usize)
         }
 
         Seeking::Issue {
-            todo_idx: todo_idx,
-            fixme_idx: fixme_idx,
+            todo_idx,
+            fixme_idx,
         }
     }
 
@@ -213,10 +213,7 @@ fn inspect_number(
             NumberPart::CloseParen => {}
         }
 
-        self.state = Seeking::Number {
-            part: part,
-            issue: issue,
-        };
+        self.state = Seeking::Number { part, issue };
 
         IssueClassification::None
     }

src/items.rs

@@ -138,7 +138,7 @@ fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Ite
                 .iter()
                 .map(|i| BodyElement::ForeignItem(i))
                 .collect(),
-            span: span,
+            span,
         }
     }
 }
@@ -169,8 +169,8 @@ pub fn new(
         vis: ast::Visibility,
     ) -> FnSig<'a> {
         FnSig {
-            decl: decl,
-            generics: generics,
+            decl,
+            generics,
             abi: abi::Abi::Rust,
             constness: ast::Constness::NotConst,
             defaultness: ast::Defaultness::Final,
@@ -189,7 +189,7 @@ pub fn from_method_sig(
             defaultness: ast::Defaultness::Final,
             abi: method_sig.abi,
             decl: &*method_sig.decl,
-            generics: generics,
+            generics,
             visibility: ast::Visibility::Inherited,
         }
     }
@@ -202,12 +202,12 @@ pub fn from_fn_kind(
     ) -> FnSig<'a> {
         match *fn_kind {
             visit::FnKind::ItemFn(_, unsafety, constness, abi, visibility, _) => FnSig {
-                decl: decl,
-                generics: generics,
-                abi: abi,
+                decl,
+                generics,
+                abi,
                 constness: constness.node,
                 defaultness: defualtness,
-                unsafety: unsafety,
+                unsafety,
                 visibility: visibility.clone(),
             },
             visit::FnKind::Method(_, method_sig, vis, _) => {
@@ -510,7 +510,7 @@ fn format_variant_list(
             separator: ",",
             trailing_separator: self.config.trailing_comma(),
             separator_place: SeparatorPlace::Back,
-            shape: shape,
+            shape,
             ends_with_newline: true,
             preserve_newline: true,
             config: self.config,
@@ -888,10 +888,10 @@ pub fn from_item(item: &'a ast::Item) -> Self {
             _ => unreachable!(),
         };
         StructParts {
-            prefix: prefix,
+            prefix,
             ident: item.ident,
             vis: &item.vis,
-            def: def,
+            def,
             generics: Some(generics),
             span: item.span,
         }
@@ -1502,11 +1502,11 @@ pub fn from_item(item: &'a ast::Item) -> Self {
             _ => unreachable!(),
         };
         StaticParts {
-            prefix: prefix,
+            prefix,
             vis: &item.vis,
             ident: item.ident,
-            ty: ty,
-            mutability: mutability,
+            ty,
+            mutability,
             expr_opt: Some(expr),
             defaultness: None,
             span: item.span,
@@ -1522,7 +1522,7 @@ pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
             prefix: "const",
             vis: &ast::Visibility::Inherited,
             ident: ti.ident,
-            ty: ty,
+            ty,
             mutability: ast::Mutability::Immutable,
             expr_opt: expr_opt.as_ref(),
             defaultness: None,
@@ -1539,7 +1539,7 @@ pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
             prefix: "const",
             vis: &ii.vis,
             ident: ii.ident,
-            ty: ty,
+            ty,
             mutability: ast::Mutability::Immutable,
             expr_opt: Some(expr),
             defaultness: Some(ii.defaultness),
@@ -1811,7 +1811,7 @@ fn rewrite_fn_base(
     let one_line_budget = context.budget(used_width + overhead);
     let shape = Shape {
         width: one_line_budget,
-        indent: indent,
+        indent,
         offset: used_width,
     };
     let fd = fn_sig.decl;
@@ -2078,8 +2078,8 @@ struct WhereClauseOption {
 impl WhereClauseOption {
     pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
         WhereClauseOption {
-            suppress_comma: suppress_comma,
-            snuggle: snuggle,
+            suppress_comma,
+            snuggle,
             compress_where: false,
         }
     }
@@ -2226,7 +2226,7 @@ enum ArgumentKind<'a> {
     debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: if variadic {
             SeparatorTactic::Never
@@ -2397,7 +2397,7 @@ pub fn format_generics_item_list<I>(
         one_line_budget,
     );
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: if context.config.indent_style() == IndentStyle::Visual {
             SeparatorTactic::Never
@@ -2405,7 +2405,7 @@ pub fn format_generics_item_list<I>(
             context.config.trailing_comma()
         },
         separator_place: SeparatorPlace::Back,
-        shape: shape,
+        shape,
         ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
         preserve_newline: true,
         config: context.config,
@@ -2630,7 +2630,7 @@ fn rewrite_where_clause(
     }
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: comma_tactic,
         separator_place: SeparatorPlace::Back,

src/lib.rs

@@ -449,7 +449,7 @@ fn format_lines(
                         line: cur_line,
                         kind: error_kind,
                         is_comment: kind.is_comment(),
-                        is_string: is_string,
+                        is_string,
                         line_buffer: line_buffer.clone(),
                     });
                 }

src/lists.rs

@@ -690,15 +690,15 @@ fn next(&mut self) -> Option<Self::Item> {
             };
 
             ListItem {
-                pre_comment: pre_comment,
-                pre_comment_style: pre_comment_style,
+                pre_comment,
+                pre_comment_style,
                 item: if self.inner.peek().is_none() && self.leave_last {
                     None
                 } else {
                     (self.get_item_string)(&item)
                 },
-                post_comment: post_comment,
-                new_lines: new_lines,
+                post_comment,
+                new_lines,
             }
         })
     }
@@ -724,16 +724,16 @@ pub fn itemize_list<'a, T, I, F1, F2, F3>(
     F3: Fn(&T) -> Option<String>,
 {
     ListItems {
-        codemap: codemap,
+        codemap,
         inner: inner.peekable(),
-        get_lo: get_lo,
-        get_hi: get_hi,
-        get_item_string: get_item_string,
-        prev_span_end: prev_span_end,
-        next_span_start: next_span_start,
-        terminator: terminator,
-        separator: separator,
-        leave_last: leave_last,
+        get_lo,
+        get_hi,
+        get_item_string,
+        prev_span_end,
+        next_span_start,
+        terminator,
+        separator,
+        leave_last,
     }
 }
 
@@ -841,7 +841,7 @@ pub fn struct_lit_formatting<'a>(
     let ends_with_newline = context.config.indent_style() != IndentStyle::Visual
         && tactic == DefinitiveListTactic::Vertical;
     ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: if force_no_trailing_comma {
             SeparatorTactic::Never
@@ -849,8 +849,8 @@ pub fn struct_lit_formatting<'a>(
             context.config.trailing_comma()
         },
         separator_place: SeparatorPlace::Back,
-        shape: shape,
-        ends_with_newline: ends_with_newline,
+        shape,
+        ends_with_newline,
         preserve_newline: true,
         config: context.config,
     }

src/rustfmt_diff.rs

@@ -31,7 +31,7 @@ pub struct Mismatch {
 impl Mismatch {
     fn new(line_number: u32) -> Mismatch {
         Mismatch {
-            line_number: line_number,
+            line_number,
             lines: Vec::new(),
         }
     }

src/shape.rs

@@ -29,8 +29,8 @@ pub struct Indent {
 impl Indent {
     pub fn new(block_indent: usize, alignment: usize) -> Indent {
         Indent {
-            block_indent: block_indent,
-            alignment: alignment,
+            block_indent,
+            alignment,
         }
     }
 
@@ -161,8 +161,8 @@ impl Shape {
     //        |<--->|    width
     pub fn legacy(width: usize, indent: Indent) -> Shape {
         Shape {
-            width: width,
-            indent: indent,
+            width,
+            indent,
             offset: indent.alignment,
         }
     }
@@ -170,7 +170,7 @@ pub fn legacy(width: usize, indent: Indent) -> Shape {
     pub fn indented(indent: Indent, config: &Config) -> Shape {
         Shape {
             width: config.max_width().checked_sub(indent.width()).unwrap_or(0),
-            indent: indent,
+            indent,
             offset: indent.alignment,
         }
     }
@@ -187,9 +187,9 @@ pub fn with_max_width(&self, config: &Config) -> Shape {
 
     pub fn offset(width: usize, indent: Indent, offset: usize) -> Shape {
         Shape {
-            width: width,
-            indent: indent,
-            offset: offset,
+            width,
+            indent,
+            offset,
         }
     }
 

src/string.rs

@@ -36,9 +36,9 @@ pub fn new(shape: Shape, config: &'a Config) -> StringFormat<'a> {
             closer: "\"",
             line_start: " ",
             line_end: "\\",
-            shape: shape,
+            shape,
             trim_end: false,
-            config: config,
+            config,
         }
     }
 }

src/types.rs

@@ -352,7 +352,7 @@ enum ArgumentKind<T>
     );
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: if !context.use_block_indent() || variadic {
             SeparatorTactic::Never

src/vertical.rs

@@ -247,7 +247,7 @@ fn rewrite_aligned_items_inner<T: AlignedItem>(
     );
 
     let fmt = ListFormatting {
-        tactic: tactic,
+        tactic,
         separator: ",",
         trailing_separator: context.config.trailing_comma(),
         separator_place: SeparatorPlace::Back,

src/visitor.rs

@@ -591,14 +591,14 @@ pub fn from_codemap(
         snippet_provider: &'a SnippetProvider,
     ) -> FmtVisitor<'a> {
         FmtVisitor {
-            parse_session: parse_session,
+            parse_session,
             codemap: parse_session.codemap(),
             buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
             last_pos: BytePos(0),
             block_indent: Indent::empty(),
-            config: config,
+            config,
             is_if_else_block: false,
-            snippet_provider: snippet_provider,
+            snippet_provider,
             line_number: 0,
             skipped_range: vec![],
         }

tests/source/configs/use_field_init_shorthand/false.rs

@@ -0,0 +1,19 @@
+// rustfmt-use_field_init_shorthand: false
+// Use field initialization shorthand if possible.
+
+fn main() {
+    let a = Foo {
+        x: x,
+        y: y,
+        z: z,
+    };
+
+    let b = Bar {
+        x: x,
+        y: y,
+        #[attr]
+        z: z,
+        #[rustfmt_skip]
+        skipped: skipped,
+    };
+}

tests/source/configs/use_field_init_shorthand/true.rs

@@ -0,0 +1,19 @@
+// rustfmt-use_field_init_shorthand: true
+// Use field initialization shorthand if possible.
+
+fn main() {
+    let a = Foo {
+        x: x,
+        y: y,
+        z: z,
+    };
+
+    let b = Bar {
+        x: x,
+        y: y,
+        #[attr]
+        z: z,
+        #[rustfmt_skip]
+        skipped: skipped,
+    };
+}

tests/target/configs/use_field_init_shorthand/false.rs

@@ -0,0 +1,15 @@
+// rustfmt-use_field_init_shorthand: false
+// Use field initialization shorthand if possible.
+
+fn main() {
+    let a = Foo { x: x, y: y, z: z };
+
+    let b = Bar {
+        x: x,
+        y: y,
+        #[attr]
+        z: z,
+        #[rustfmt_skip]
+        skipped: skipped,
+    };
+}

tests/target/configs/use_field_init_shorthand/true.rs

@@ -0,0 +1,15 @@
+// rustfmt-use_field_init_shorthand: true
+// Use field initialization shorthand if possible.
+
+fn main() {
+    let a = Foo { x, y, z };
+
+    let b = Bar {
+        x,
+        y,
+        #[attr]
+        z,
+        #[rustfmt_skip]
+        skipped: skipped,
+    };
+}

tests/target/impl.rs

@@ -13,7 +13,7 @@ impl<V> Test<V>
     pub fn new(value: V) -> Self {
         Test {
             cloned_value: value.clone(),
-            value: value,
+            value,
         }
     }
 }