Migrate all crates to the 2018 edition

Most of the CLI crates were already in the 2018 edition, and it turns
out that one of the macro crates was already in the 2018 edition so we
may as well move everything to the 2018 edition!

Always nice to remove those `extern crate` statements nowadays!

This commit also does a `cargo fmt --all` to make sure we're conforming
with style again.

crates/cli-support/src/js/js2rust.rs

@@ -357,7 +357,8 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
                     return Ok(self);
                 }
                 Descriptor::RustStruct(ref s) => {
-                    self.js_arguments.push((name.clone(), format!("{} | undefined", s)));
+                    self.js_arguments
+                        .push((name.clone(), format!("{} | undefined", s)));
                     self.prelude(&format!("let ptr{} = 0;", i));
                     self.prelude(&format!("if ({0} !== null && {0} !== undefined) {{", name));
                     self.assert_class(&name, s);
@@ -659,7 +660,8 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
                 Descriptor::RustStruct(ref name) => {
                     self.ret_ty = format!("{} | undefined", name);
                     self.cx.require_class_wrap(name);
-                    self.ret_expr = format!("
+                    self.ret_expr = format!(
+                        "
                         const ptr = RET;
                         return ptr === 0 ? undefined : {}.__wrap(ptr);
                     ",
@@ -830,7 +832,7 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
 
     fn assert_class(&mut self, arg: &str, class: &str) {
         if !self.cx.config.debug {
-            return
+            return;
         }
         self.cx.expose_assert_class();
         self.prelude(&format!("_assertClass({}, {});", arg, class));
@@ -838,7 +840,7 @@ impl<'a, 'b> Js2Rust<'a, 'b> {
 
     fn assert_not_moved(&mut self, arg: &str) {
         if !self.cx.config.debug {
-            return
+            return;
         }
         self.prelude(&format!(
             "\

crates/cli-support/src/js/mod.rs

@@ -2,7 +2,7 @@ use crate::decode;
 use crate::descriptor::{Descriptor, VectorKind};
 use crate::{Bindgen, EncodeInto, OutputMode};
 use failure::{bail, Error, ResultExt};
-use std::collections::{HashMap, HashSet, BTreeMap};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::env;
 use std::fs;
 use walrus::{MemoryId, Module};
@@ -2998,8 +2998,10 @@ impl<'a, 'b> SubContext<'a, 'b> {
             return Ok(());
         }
         if !self.cx.config.mode.nodejs() && !self.cx.config.mode.bundler() {
-            bail!("NPM dependencies have been specified in `{}` but \
-                   this is only compatible with the `bundler` and `nodejs` targets");
+            bail!(
+                "NPM dependencies have been specified in `{}` but \
+                 this is only compatible with the `bundler` and `nodejs` targets"
+            );
         }
         let contents = fs::read_to_string(path).context(format!("failed to read `{}`", path))?;
         let json: serde_json::Value = serde_json::from_str(&contents)?;

crates/cli-support/src/js/rust2js.rs

@@ -225,7 +225,10 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
                 }
                 Descriptor::RustStruct(ref class) => {
                     self.cx.require_class_wrap(class);
-                    let assign = format!("let c{0} = {0} === 0 ? undefined : {1}.__wrap({0});", abi, class);
+                    let assign = format!(
+                        "let c{0} = {0} === 0 ? undefined : {1}.__wrap({0});",
+                        abi, class
+                    );
                     self.prelude(&assign);
                     self.js_arguments.push(format!("c{}", abi));
                     return Ok(());

crates/cli-support/src/lib.rs

@@ -1,7 +1,7 @@
 #![doc(html_root_url = "https://docs.rs/wasm-bindgen-cli-support/0.2")]
 
 use failure::{bail, Error, ResultExt};
-use std::collections::{BTreeSet, BTreeMap};
+use std::collections::{BTreeMap, BTreeSet};
 use std::env;
 use std::fs;
 use std::mem;