Merge pull request #3335 from h-michael/rust-2018

Rust 2018 idioms

Author: topecongiro

src/attr.rs

@@ -75,7 +75,7 @@ fn argument_shape(
     right: usize,
     combine: bool,
     shape: Shape,
-    context: &RewriteContext,
+    context: &RewriteContext<'_>,
 ) -> Option<Shape> {
     match context.config.indent_style() {
         IndentStyle::Block => {
@@ -100,7 +100,7 @@ fn format_derive(
     derive_args: &[Span],
     prefix: &str,
     shape: Shape,
-    context: &RewriteContext,
+    context: &RewriteContext<'_>,
 ) -> Option<String> {
     let mut result = String::with_capacity(128);
     result.push_str(prefix);
@@ -133,7 +133,7 @@ fn format_derive(
 /// Returns the first group of attributes that fills the given predicate.
 /// We consider two doc comments are in different group if they are separated by normal comments.
 fn take_while_with_pred<'a, P>(
-    context: &RewriteContext,
+    context: &RewriteContext<'_>,
     attrs: &'a [ast::Attribute],
     pred: P,
 ) -> &'a [ast::Attribute]
@@ -164,7 +164,7 @@ where
 
 /// Rewrite the any doc comments which come before any other attributes.
 fn rewrite_initial_doc_comments(
-    context: &RewriteContext,
+    context: &RewriteContext<'_>,
     attrs: &[ast::Attribute],
     shape: Shape,
 ) -> Option<(usize, Option<String>)> {
@@ -193,7 +193,7 @@ fn rewrite_initial_doc_comments(
 }
 
 impl Rewrite for ast::NestedMetaItem {
-    fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
         match self.node {
             ast::NestedMetaItemKind::MetaItem(ref meta_item) => meta_item.rewrite(context, shape),
             ast::NestedMetaItemKind::Literal(ref l) => rewrite_literal(context, l, shape),
@@ -221,7 +221,7 @@ fn has_newlines_before_after_comment(comment: &str) -> (&str, &str) {
 }
 
 impl Rewrite for ast::MetaItem {
-    fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
         Some(match self.node {
             ast::MetaItemKind::Word => {
                 rewrite_path(context, PathContext::Type, None, &self.ident, shape)?
@@ -268,7 +268,7 @@ fn format_arg_list<I, T, F1, F2, F3>(
     get_hi: F2,
     get_item_string: F3,
     span: Span,
-    context: &RewriteContext,
+    context: &RewriteContext<'_>,
     shape: Shape,
     one_line_shape: Shape,
     one_line_limit: Option<usize>,
@@ -318,7 +318,7 @@ where
 }
 
 impl Rewrite for ast::Attribute {
-    fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
         let snippet = context.snippet(self.span);
         if self.is_sugared_doc {
             rewrite_doc_comment(snippet, shape.comment(context.config), context.config)
@@ -365,7 +365,7 @@ impl Rewrite for ast::Attribute {
 }
 
 impl<'a> Rewrite for [ast::Attribute] {
-    fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
         if self.is_empty() {
             return Some(String::new());
         }

src/bin/main.rs

@@ -8,11 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate env_logger;
+use env_logger;
 #[macro_use]
 extern crate failure;
-extern crate getopts;
-extern crate rustfmt_nightly as rustfmt;
+
+use rustfmt_nightly as rustfmt;
 
 use std::env;
 use std::fs::File;
@@ -296,7 +296,7 @@ fn format(
     Ok(exit_code)
 }
 
-fn format_and_emit_report<T: Write>(session: &mut Session<T>, input: Input) {
+fn format_and_emit_report<T: Write>(session: &mut Session<'_, T>, input: Input) {
     match session.format(input) {
         Ok(report) => {
             if report.has_warnings() {

src/cargo-fmt/main.rs

@@ -13,9 +13,8 @@
 #![cfg(not(test))]
 #![deny(warnings)]
 
-extern crate cargo_metadata;
-extern crate getopts;
-extern crate serde_json as json;
+use cargo_metadata;
+use getopts;
 
 use std::collections::{HashMap, HashSet};
 use std::env;

src/chains.rs

@@ -84,7 +84,11 @@ use crate::utils::{
     trimmed_last_line_width, wrap_str,
 };
 
-pub fn rewrite_chain(expr: &ast::Expr, context: &RewriteContext, shape: Shape) -> Option<String> {
+pub fn rewrite_chain(
+    expr: &ast::Expr,
+    context: &RewriteContext<'_>,
+    shape: Shape,
+) -> Option<String> {
     let chain = Chain::from_ast(expr, context);
     debug!("rewrite_chain {:?} {:?}", chain, shape);
 
@@ -128,7 +132,7 @@ enum ChainItemKind {
 }
 
 impl ChainItemKind {
-    fn is_block_like(&self, context: &RewriteContext, reps: &str) -> bool {
+    fn is_block_like(&self, context: &RewriteContext<'_>, reps: &str) -> bool {
         match self {
             ChainItemKind::Parent(ref expr) => utils::is_block_expr(context, expr, reps),
             ChainItemKind::MethodCall(..)
@@ -147,7 +151,7 @@ impl ChainItemKind {
         }
     }
 
-    fn from_ast(context: &RewriteContext, expr: &ast::Expr) -> (ChainItemKind, Span) {
+    fn from_ast(context: &RewriteContext<'_>, expr: &ast::Expr) -> (ChainItemKind, Span) {
         let (kind, span) = match expr.node {
             ast::ExprKind::MethodCall(ref segment, ref expressions) => {
                 let types = if let Some(ref generic_args) = segment.args {
@@ -182,7 +186,7 @@ impl ChainItemKind {
 }
 
 impl Rewrite for ChainItem {
-    fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
         let shape = shape.sub_width(self.tries)?;
         let rewrite = match self.kind {
             ChainItemKind::Parent(ref expr) => expr.rewrite(context, shape)?,
@@ -204,7 +208,7 @@ impl Rewrite for ChainItem {
 }
 
 impl ChainItem {
-    fn new(context: &RewriteContext, expr: &ast::Expr, tries: usize) -> ChainItem {
+    fn new(context: &RewriteContext<'_>, expr: &ast::Expr, tries: usize) -> ChainItem {
         let (kind, span) = ChainItemKind::from_ast(context, expr);
         ChainItem { kind, tries, span }
     }
@@ -229,7 +233,7 @@ impl ChainItem {
         types: &[ast::GenericArg],
         args: &[ptr::P<ast::Expr>],
         span: Span,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
     ) -> Option<String> {
         let type_str = if types.is_empty() {
@@ -254,7 +258,7 @@ struct Chain {
 }
 
 impl Chain {
-    fn from_ast(expr: &ast::Expr, context: &RewriteContext) -> Chain {
+    fn from_ast(expr: &ast::Expr, context: &RewriteContext<'_>) -> Chain {
         let subexpr_list = Self::make_subexpr_list(expr, context);
 
         // Un-parse the expression tree into ChainItems
@@ -376,7 +380,7 @@ impl Chain {
 
     // Returns a Vec of the prefixes of the chain.
     // E.g., for input `a.b.c` we return [`a.b.c`, `a.b`, 'a']
-    fn make_subexpr_list(expr: &ast::Expr, context: &RewriteContext) -> Vec<ast::Expr> {
+    fn make_subexpr_list(expr: &ast::Expr, context: &RewriteContext<'_>) -> Vec<ast::Expr> {
         let mut subexpr_list = vec![expr.clone()];
 
         while let Some(subexpr) = Self::pop_expr_chain(subexpr_list.last().unwrap(), context) {
@@ -388,7 +392,7 @@ impl Chain {
 
     // Returns the expression's subexpression, if it exists. When the subexpr
     // is a try! macro, we'll convert it to shorthand when the option is set.
-    fn pop_expr_chain(expr: &ast::Expr, context: &RewriteContext) -> Option<ast::Expr> {
+    fn pop_expr_chain(expr: &ast::Expr, context: &RewriteContext<'_>) -> Option<ast::Expr> {
         match expr.node {
             ast::ExprKind::MethodCall(_, ref expressions) => {
                 Some(Self::convert_try(&expressions[0], context))
@@ -400,7 +404,7 @@ impl Chain {
         }
     }
 
-    fn convert_try(expr: &ast::Expr, context: &RewriteContext) -> ast::Expr {
+    fn convert_try(expr: &ast::Expr, context: &RewriteContext<'_>) -> ast::Expr {
         match expr.node {
             ast::ExprKind::Mac(ref mac) if context.config.use_try_shorthand() => {
                 if let Some(subexpr) = convert_try_mac(mac, context) {
@@ -415,12 +419,16 @@ impl Chain {
 }
 
 impl Rewrite for Chain {
-    fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
         debug!("rewrite chain {:?} {:?}", self, shape);
 
         let mut formatter = match context.config.indent_style() {
-            IndentStyle::Block => Box::new(ChainFormatterBlock::new(self)) as Box<ChainFormatter>,
-            IndentStyle::Visual => Box::new(ChainFormatterVisual::new(self)) as Box<ChainFormatter>,
+            IndentStyle::Block => {
+                Box::new(ChainFormatterBlock::new(self)) as Box<dyn ChainFormatter>
+            }
+            IndentStyle::Visual => {
+                Box::new(ChainFormatterVisual::new(self)) as Box<dyn ChainFormatter>
+            }
         };
 
         formatter.format_root(&self.parent, context, shape)?;
@@ -455,18 +463,18 @@ trait ChainFormatter {
     fn format_root(
         &mut self,
         parent: &ChainItem,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
     ) -> Option<()>;
-    fn child_shape(&self, context: &RewriteContext, shape: Shape) -> Option<Shape>;
-    fn format_children(&mut self, context: &RewriteContext, child_shape: Shape) -> Option<()>;
+    fn child_shape(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<Shape>;
+    fn format_children(&mut self, context: &RewriteContext<'_>, child_shape: Shape) -> Option<()>;
     fn format_last_child(
         &mut self,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
         child_shape: Shape,
     ) -> Option<()>;
-    fn join_rewrites(&self, context: &RewriteContext, child_shape: Shape) -> Option<String>;
+    fn join_rewrites(&self, context: &RewriteContext<'_>, child_shape: Shape) -> Option<String>;
     // Returns `Some` if the chain is only a root, None otherwise.
     fn pure_root(&mut self) -> Option<String>;
 }
@@ -540,7 +548,7 @@ impl<'a> ChainFormatterShared<'a> {
     fn format_last_child(
         &mut self,
         may_extend: bool,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
         child_shape: Shape,
     ) -> Option<()> {
@@ -633,7 +641,7 @@ impl<'a> ChainFormatterShared<'a> {
         Some(())
     }
 
-    fn join_rewrites(&self, context: &RewriteContext, child_shape: Shape) -> Option<String> {
+    fn join_rewrites(&self, context: &RewriteContext<'_>, child_shape: Shape) -> Option<String> {
         let connector = if self.fits_single_line {
             // Yay, we can put everything on one line.
             Cow::from("")
@@ -682,7 +690,7 @@ impl<'a> ChainFormatter for ChainFormatterBlock<'a> {
     fn format_root(
         &mut self,
         parent: &ChainItem,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
     ) -> Option<()> {
         let mut root_rewrite: String = parent.rewrite(context, shape)?;
@@ -713,7 +721,7 @@ impl<'a> ChainFormatter for ChainFormatterBlock<'a> {
         Some(())
     }
 
-    fn child_shape(&self, context: &RewriteContext, shape: Shape) -> Option<Shape> {
+    fn child_shape(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<Shape> {
         Some(
             if self.root_ends_with_block {
                 shape.block_indent(0)
@@ -724,7 +732,7 @@ impl<'a> ChainFormatter for ChainFormatterBlock<'a> {
         )
     }
 
-    fn format_children(&mut self, context: &RewriteContext, child_shape: Shape) -> Option<()> {
+    fn format_children(&mut self, context: &RewriteContext<'_>, child_shape: Shape) -> Option<()> {
         for item in &self.shared.children[..self.shared.children.len() - 1] {
             let rewrite = item.rewrite(context, child_shape)?;
             self.shared.rewrites.push(rewrite);
@@ -734,15 +742,15 @@ impl<'a> ChainFormatter for ChainFormatterBlock<'a> {
 
     fn format_last_child(
         &mut self,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
         child_shape: Shape,
     ) -> Option<()> {
         self.shared
             .format_last_child(true, context, shape, child_shape)
     }
 
-    fn join_rewrites(&self, context: &RewriteContext, child_shape: Shape) -> Option<String> {
+    fn join_rewrites(&self, context: &RewriteContext<'_>, child_shape: Shape) -> Option<String> {
         self.shared.join_rewrites(context, child_shape)
     }
 
@@ -771,7 +779,7 @@ impl<'a> ChainFormatter for ChainFormatterVisual<'a> {
     fn format_root(
         &mut self,
         parent: &ChainItem,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
     ) -> Option<()> {
         let parent_shape = shape.visual_indent(0);
@@ -811,14 +819,14 @@ impl<'a> ChainFormatter for ChainFormatterVisual<'a> {
         Some(())
     }
 
-    fn child_shape(&self, context: &RewriteContext, shape: Shape) -> Option<Shape> {
+    fn child_shape(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<Shape> {
         shape
             .with_max_width(context.config)
             .offset_left(self.offset)
             .map(|s| s.visual_indent(0))
     }
 
-    fn format_children(&mut self, context: &RewriteContext, child_shape: Shape) -> Option<()> {
+    fn format_children(&mut self, context: &RewriteContext<'_>, child_shape: Shape) -> Option<()> {
         for item in &self.shared.children[..self.shared.children.len() - 1] {
             let rewrite = item.rewrite(context, child_shape)?;
             self.shared.rewrites.push(rewrite);
@@ -828,15 +836,15 @@ impl<'a> ChainFormatter for ChainFormatterVisual<'a> {
 
     fn format_last_child(
         &mut self,
-        context: &RewriteContext,
+        context: &RewriteContext<'_>,
         shape: Shape,
         child_shape: Shape,
     ) -> Option<()> {
         self.shared
             .format_last_child(false, context, shape, child_shape)
     }
 
-    fn join_rewrites(&self, context: &RewriteContext, child_shape: Shape) -> Option<String> {
+    fn join_rewrites(&self, context: &RewriteContext<'_>, child_shape: Shape) -> Option<String> {
         self.shared.join_rewrites(context, child_shape)
     }