Address all clippy lints

These changes do not change the behaviour of the
code and should be non-controversial.

cli/build/main.rs

@@ -28,12 +28,12 @@ pub enum Error {
 impl std::fmt::Display for Error {
 	fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
 		use self::Error::*;
-		match *self {
-			Io(ref io) => write!(f, "Generic i/o error: {}", io),
-			FailedToCopy(ref msg) => write!(f, "{}. Have you tried to run \"cargo build\"?", msg),
-			Decoding(ref err, ref file) => write!(f, "Decoding error ({}). Must be a valid wasm file {}. Pointed wrong file?", err, file),
-			Encoding(ref err) => write!(f, "Encoding error ({}). Almost impossible to happen, no free disk space?", err),
-			Build(ref err) => write!(f, "Build error: {}", err)
+		match self {
+			Io(io) => write!(f, "Generic i/o error: {}", io),
+			FailedToCopy(msg) => write!(f, "{}. Have you tried to run \"cargo build\"?", msg),
+			Decoding(err, file) => write!(f, "Decoding error ({}). Must be a valid wasm file {}. Pointed wrong file?", err, file),
+			Encoding(err) => write!(f, "Encoding error ({}). Almost impossible to happen, no free disk space?", err),
+			Build(err) => write!(f, "Build error: {}", err)
 		}
 	}
 }
@@ -163,9 +163,9 @@ fn do_main() -> Result<(), Error> {
 		None
 	};
 
-	let public_api_entries = matches.value_of("public_api")
-		.map(|val| val.split(",").collect())
-		.unwrap_or(Vec::new());
+	let public_api_entries: Vec<_> = matches.value_of("public_api")
+		.map(|val| val.split(',').collect())
+		.unwrap_or_default();
 
 	let target_runtime = match matches.value_of("target-runtime").expect("target-runtime has a default value; qed") {
 		"pwasm" => TargetRuntime::pwasm(),

cli/build/source.rs

@@ -17,8 +17,8 @@ pub struct SourceInput<'a> {
 impl<'a> SourceInput<'a> {
 	pub fn new<'b>(target_dir: &'b str, bin_name: &'b str) -> SourceInput<'b> {
 		SourceInput {
-			target_dir: target_dir,
-			bin_name: bin_name,
+			target_dir,
+			bin_name,
 			final_name: bin_name,
 			target: SourceTarget::Emscripten,
 		}

cli/check/main.rs

@@ -11,7 +11,7 @@ fn fail(msg: &str) -> ! {
 	std::process::exit(1)
 }
 
-const ALLOWED_IMPORTS: &'static [&'static str] = &[
+const ALLOWED_IMPORTS: &[&str] = &[
 	"ret",
 	"storage_read",
 	"storage_write",
@@ -54,14 +54,14 @@ fn main() {
 	let module = parity_wasm::deserialize_file(&input).expect("Input module deserialization failed");
 
 	for section in module.sections() {
-		match *section {
-			elements::Section::Import(ref import_section) => {
+		match section {
+			elements::Section::Import(import_section) => {
 				let mut has_imported_memory_properly_named = false;
 				for entry in import_section.entries() {
 					if entry.module() != "env" {
 						fail("All imports should be from env");
 					}
-					match *entry.external() {
+					match entry.external() {
 						elements::External::Function(_) => {
 							if !ALLOWED_IMPORTS.contains(&entry.field()) {
 								fail(&format!("'{}' is not supported by the runtime", entry.field()));