Migrate to 2018 edition

Cargo.toml

@@ -2,6 +2,7 @@
 name = "cargo-tree"
 version = "0.23.0"
 authors = ["Steven Fackler <[email protected]>"]
+edition = "2018"
 license = "MIT/Apache-2.0"
 description = "A Cargo subcommand that visualizes a crate's dependency graph in a tree-like format"
 repository = "https://github.com/sfackler/cargo-tree"

src/format/mod.rs

@@ -1,9 +1,9 @@
-use cargo::core::PackageId;
 use cargo::core::manifest::ManifestMetadata;
+use cargo::core::PackageId;
 use std::error::Error;
 use std::fmt;
 
-use format::parse::{Parser, RawChunk};
+use crate::format::parse::{Parser, RawChunk};
 
 mod parse;
 
@@ -17,7 +17,7 @@ enum Chunk {
 pub struct Pattern(Vec<Chunk>);
 
 impl Pattern {
-    pub fn new(format: &str) -> Result<Pattern, Box<Error>> {
+    pub fn new(format: &str) -> Result<Pattern, Box<dyn Error>> {
         let mut chunks = vec![];
 
         for raw in Parser::new(format) {
@@ -57,17 +57,21 @@ pub struct Display<'a> {
 }
 
 impl<'a> fmt::Display for Display<'a> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         for chunk in &self.pattern.0 {
             match *chunk {
-                Chunk::Raw(ref s) => try!(fmt.write_str(s)),
-                Chunk::Package => try!(write!(fmt, "{}", self.package)),
-                Chunk::License => if let Some(ref license) = self.metadata.license {
-                    try!(write!(fmt, "{}", license))
-                },
-                Chunk::Repository => if let Some(ref repository) = self.metadata.repository {
-                    try!(write!(fmt, "{}", repository))
-                },
+                Chunk::Raw(ref s) => fmt.write_str(s)?,
+                Chunk::Package => write!(fmt, "{}", self.package)?,
+                Chunk::License => {
+                    if let Some(ref license) = self.metadata.license {
+                        write!(fmt, "{}", license)?
+                    }
+                }
+                Chunk::Repository => {
+                    if let Some(ref repository) = self.metadata.repository {
+                        write!(fmt, "{}", repository)?
+                    }
+                }
             }
         }
 

src/format/parse.rs

@@ -1,5 +1,5 @@
-use std::str;
 use std::iter;
+use std::str;
 
 pub enum RawChunk<'a> {
     Text(&'a str),

src/main.rs

@@ -1,10 +1,3 @@
-extern crate cargo;
-extern crate env_logger;
-#[macro_use]
-extern crate failure;
-extern crate petgraph;
-extern crate structopt;
-
 use cargo::core::dependency::Kind;
 use cargo::core::manifest::ManifestMetadata;
 use cargo::core::package::PackageSet;
@@ -15,6 +8,7 @@ use cargo::core::{Package, PackageId, Resolve, Workspace};
 use cargo::ops;
 use cargo::util::{self, important_paths, CargoResult, Cfg, Rustc};
 use cargo::{CliResult, Config};
+use failure::bail;
 use petgraph::graph::NodeIndex;
 use petgraph::visit::EdgeRef;
 use petgraph::EdgeDirection;
@@ -25,7 +19,7 @@ use std::str::{self, FromStr};
 use structopt::clap::AppSettings;
 use structopt::StructOpt;
 
-use format::Pattern;
+use crate::format::Pattern;
 
 mod format;
 
@@ -62,23 +56,15 @@ struct Args {
     /// Set the target triple
     target: Option<String>,
     /// Directory for all generated artifacts
-    #[structopt(
-        long = "target-dir",
-        value_name = "DIRECTORY",
-        parse(from_os_str)
-    )]
+    #[structopt(long = "target-dir", value_name = "DIRECTORY", parse(from_os_str))]
     target_dir: Option<PathBuf>,
     #[structopt(long = "all-targets")]
     /// Return dependencies for all targets. By default only the host target is matched.
     all_targets: bool,
     #[structopt(long = "no-dev-dependencies")]
     /// Skip dev dependencies.
     no_dev_dependencies: bool,
-    #[structopt(
-        long = "manifest-path",
-        value_name = "PATH",
-        parse(from_os_str)
-    )]
+    #[structopt(long = "manifest-path", value_name = "PATH", parse(from_os_str))]
     /// Path to Cargo.toml
     manifest_path: Option<PathBuf>,
     #[structopt(long = "invert", short = "i")]
@@ -96,11 +82,7 @@ struct Args {
     #[structopt(long = "duplicate", short = "d")]
     /// Show only dependencies which come in multiple versions (implies -i)
     duplicates: bool,
-    #[structopt(
-        long = "charset",
-        value_name = "CHARSET",
-        default_value = "utf8"
-    )]
+    #[structopt(long = "charset", value_name = "CHARSET", default_value = "utf8")]
     /// Character set to use in output: utf8, ascii
     charset: Charset,
     #[structopt(
@@ -312,7 +294,7 @@ fn get_cfgs(rustc: &Rustc, target: &Option<String>) -> CargoResult<Option<Vec<Cf
     ))
 }
 
-fn workspace(config: &Config, manifest_path: Option<PathBuf>) -> CargoResult<Workspace> {
+fn workspace(config: &Config, manifest_path: Option<PathBuf>) -> CargoResult<Workspace<'_>> {
     let root = match manifest_path {
         Some(path) => path,
         None => important_paths::find_root_manifest_for_wd(config.cwd())?,
@@ -370,7 +352,7 @@ struct Graph<'a> {
 
 fn build_graph<'a>(
     resolve: &'a Resolve,
-    packages: &'a PackageSet,
+    packages: &'a PackageSet<'_>,
     root: PackageId,
     target: Option<&str>,
     cfgs: Option<&[Cfg]>,