Enable rust_2018_idioms warning

build.rs

@@ -13,9 +13,6 @@
 //! This build script was originally taken from the Rocket web framework:
 //! https://github.com/SergioBenitez/Rocket
 
-extern crate ansi_term;
-extern crate rustc_version;
-
 use ansi_term::Colour::Red;
 use rustc_version::{version_meta, version_meta_for, Channel, Version, VersionMeta};
 use std::env;

clippy_lints/src/copies.rs

@@ -134,7 +134,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CopyAndPaste {
 
 /// Implementation of `IF_SAME_THEN_ELSE`.
 fn lint_same_then_else(cx: &LateContext, blocks: &[&Block]) {
-    let eq: &Fn(&&Block, &&Block) -> bool = &|&lhs, &rhs| -> bool { SpanlessEq::new(cx).eq_block(lhs, rhs) };
+    let eq: &dyn Fn(&&Block, &&Block) -> bool = &|&lhs, &rhs| -> bool { SpanlessEq::new(cx).eq_block(lhs, rhs) };
 
     if let Some((i, j)) = search_same_sequenced(blocks, eq) {
         span_note_and_lint(
@@ -150,13 +150,13 @@ fn lint_same_then_else(cx: &LateContext, blocks: &[&Block]) {
 
 /// Implementation of `IFS_SAME_COND`.
 fn lint_same_cond(cx: &LateContext, conds: &[&Expr]) {
-    let hash: &Fn(&&Expr) -> u64 = &|expr| -> u64 {
+    let hash: &dyn Fn(&&Expr) -> u64 = &|expr| -> u64 {
         let mut h = SpanlessHash::new(cx, cx.tables);
         h.hash_expr(expr);
         h.finish()
     };
 
-    let eq: &Fn(&&Expr, &&Expr) -> bool = &|&lhs, &rhs| -> bool { SpanlessEq::new(cx).ignore_fn().eq_expr(lhs, rhs) };
+    let eq: &dyn Fn(&&Expr, &&Expr) -> bool = &|&lhs, &rhs| -> bool { SpanlessEq::new(cx).ignore_fn().eq_expr(lhs, rhs) };
 
     if let Some((i, j)) = search_same(conds, hash, eq) {
         span_note_and_lint(

clippy_lints/src/lib.rs

@@ -12,50 +12,23 @@
 #![feature(iterator_find_map)]
 #![feature(macro_at_most_once_rep)]
 #![feature(rust_2018_preview)]
+#![warn(rust_2018_idioms)]
 
-extern crate cargo_metadata;
 #[macro_use]
 extern crate rustc;
-extern crate rustc_target;
-extern crate rustc_typeck;
-extern crate syntax;
-extern crate syntax_pos;
 
-extern crate toml;
-
-// for unicode nfc normalization
-
-extern crate unicode_normalization;
-
-// for semver check in attrs.rs
-
-extern crate semver;
-
-// for regex checking
-
-extern crate regex_syntax;
-
-// for finding minimal boolean expressions
-
-extern crate quine_mc_cluskey;
-
-extern crate rustc_errors;
-extern crate rustc_plugin;
+use toml;
+use rustc_plugin;
 
 #[macro_use]
 extern crate matches as matches_macro;
 
-extern crate serde;
 #[macro_use]
 extern crate serde_derive;
 
 #[macro_use]
 extern crate lazy_static;
 
-extern crate itertools;
-extern crate pulldown_cmark;
-extern crate url;
-
 #[macro_use]
 extern crate if_chain;
 
@@ -211,7 +184,7 @@ pub mod zero_div_zero;
 // end lints modules, do not remove this comment, it’s used in `update_lints`
 
 mod reexport {
-    pub use syntax::ast::{Name, NodeId};
+    crate use syntax::ast::{Name, NodeId};
 }
 
 #[cfg_attr(rustfmt, rustfmt_skip)]

clippy_lints/src/literal_representation.rs

@@ -90,7 +90,7 @@ pub(super) enum Radix {
 
 impl Radix {
     /// Return a reasonable digit group size for this radix.
-    pub fn suggest_grouping(&self) -> usize {
+    crate fn suggest_grouping(&self) -> usize {
         match *self {
             Radix::Binary | Radix::Hexadecimal => 4,
             Radix::Octal | Radix::Decimal => 3,
@@ -101,19 +101,19 @@ impl Radix {
 #[derive(Debug)]
 pub(super) struct DigitInfo<'a> {
     /// Characters of a literal between the radix prefix and type suffix.
-    pub digits: &'a str,
+    crate digits: &'a str,
     /// Which radix the literal was represented in.
-    pub radix: Radix,
+    crate radix: Radix,
     /// The radix prefix, if present.
-    pub prefix: Option<&'a str>,
+    crate prefix: Option<&'a str>,
     /// The type suffix, including preceding underscore if present.
-    pub suffix: Option<&'a str>,
+    crate suffix: Option<&'a str>,
     /// True for floating-point literals.
-    pub float: bool,
+    crate float: bool,
 }
 
 impl<'a> DigitInfo<'a> {
-    pub fn new(lit: &'a str, float: bool) -> Self {
+    crate fn new(lit: &'a str, float: bool) -> Self {
         // Determine delimiter for radix prefix, if present, and radix.
         let radix = if lit.starts_with("0x") {
             Radix::Hexadecimal
@@ -160,7 +160,7 @@ impl<'a> DigitInfo<'a> {
     }
 
     /// Returns digits grouped in a sensible way.
-    pub fn grouping_hint(&self) -> String {
+    crate fn grouping_hint(&self) -> String {
         let group_size = self.radix.suggest_grouping();
         if self.digits.contains('.') {
             let mut parts = self.digits.split('.');
@@ -227,7 +227,7 @@ enum WarningType {
 }
 
 impl WarningType {
-    pub fn display(&self, grouping_hint: &str, cx: &EarlyContext, span: syntax_pos::Span) {
+    crate fn display(&self, grouping_hint: &str, cx: &EarlyContext, span: syntax_pos::Span) {
         match self {
             WarningType::UnreadableLiteral => span_lint_and_sugg(
                 cx,

clippy_lints/src/utils/conf.rs

@@ -76,6 +76,15 @@ lazy_static! {
 macro_rules! define_Conf {
     ($(#[$doc: meta] ($rust_name: ident, $rust_name_str: expr, $default: expr => $($ty: tt)+),)+) => {
         pub use self::helpers::Conf;
+        // FIXME(mati865): remove #[allow(rust_2018_idioms)] when it's fixed:
+        //
+        // warning: `extern crate` is not idiomatic in the new edition
+        //    --> src/utils/conf.rs:82:22
+        //     |
+        // 82  |               #[derive(Deserialize)]
+        //     |                        ^^^^^^^^^^^ help: convert it to a `use`
+        //
+        #[allow(rust_2018_idioms)]
         mod helpers {
             /// Type used to store lint configuration.
             #[derive(Deserialize)]
@@ -92,7 +101,7 @@ macro_rules! define_Conf {
                 mod $rust_name {
                     use serde;
                     use serde::Deserialize;
-                    pub fn deserialize<'de, D: serde::Deserializer<'de>>(deserializer: D)
+                    crate fn deserialize<'de, D: serde::Deserializer<'de>>(deserializer: D)
                     -> Result<define_Conf!(TY $($ty)+), D::Error> {
                         type T = define_Conf!(TY $($ty)+);
                         Ok(T::deserialize(deserializer).unwrap_or_else(|e| {

src/driver.rs

@@ -3,16 +3,8 @@
 #![feature(rustc_private)]
 #![allow(unknown_lints, missing_docs_in_private_items)]
 
-extern crate clippy_lints;
-extern crate getopts;
-extern crate rustc;
-extern crate rustc_codegen_utils;
-extern crate rustc_driver;
-extern crate rustc_errors;
-extern crate rustc_plugin;
-extern crate syntax;
-
-use rustc_driver::{driver::CompileController, Compilation};
+use rustc_driver::{self, driver::CompileController, Compilation};
+use rustc_plugin;
 use std::process::{exit, Command};
 
 #[allow(print_stdout)]

src/lib.rs

@@ -5,12 +5,10 @@
 #![feature(macro_vis_matcher)]
 #![allow(unknown_lints)]
 #![allow(missing_docs_in_private_items)]
+#![warn(rust_2018_idioms)]
 
-extern crate rustc_plugin;
 use rustc_plugin::Registry;
 
-extern crate clippy_lints;
-
 #[plugin_registrar]
 pub fn plugin_registrar(reg: &mut Registry) {
     reg.sess.lint_store.with_read_lock(|lint_store| {