Refactoring

1. Cargo clippy
2. Run 'cargo fmt' with import reordering options set to `true`.
3. Factor out `rewrite_lifetime_param()`.

src/bin/cargo-fmt.rs

@@ -17,15 +17,15 @@ extern crate cargo_metadata;
 extern crate getopts;
 extern crate serde_json as json;
 
+use std::collections::HashSet;
 use std::env;
 use std::fs;
 use std::hash::{Hash, Hasher};
 use std::io::{self, Write};
+use std::iter::FromIterator;
 use std::path::{Path, PathBuf};
 use std::process::{Command, ExitStatus};
 use std::str;
-use std::collections::HashSet;
-use std::iter::FromIterator;
 
 use getopts::{Matches, Options};
 
@@ -125,7 +125,7 @@ pub enum Verbosity {
 fn handle_command_status(status: Result<ExitStatus, io::Error>, opts: &getopts::Options) -> i32 {
     match status {
         Err(e) => {
-            print_usage_to_stderr(&opts, &e.to_string());
+            print_usage_to_stderr(opts, &e.to_string());
             FAILURE
         }
         Ok(status) => {
@@ -139,7 +139,7 @@ fn handle_command_status(status: Result<ExitStatus, io::Error>, opts: &getopts::
 }
 
 fn get_version(verbosity: Verbosity) -> Result<ExitStatus, io::Error> {
-    run_rustfmt(&vec![], &vec![String::from("--version")], verbosity)
+    run_rustfmt(&[], &[String::from("--version")], verbosity)
 }
 
 fn format_crate(

src/bin/rustfmt.rs

@@ -24,8 +24,8 @@ use std::str::FromStr;
 use getopts::{Matches, Options};
 
 use rustfmt::{run, FileName, Input, Summary};
-use rustfmt::file_lines::FileLines;
 use rustfmt::config::{get_toml_path, Color, Config, WriteMode};
+use rustfmt::file_lines::FileLines;
 
 type FmtError = Box<error::Error + Send + Sync>;
 type FmtResult<T> = std::result::Result<T, FmtError>;

src/types.rs

@@ -422,21 +422,9 @@ impl Rewrite for ast::WherePredicate {
 
                 let colon = type_bound_colon(context);
 
-                if bound_generic_params
-                    .iter()
-                    .filter(|p| p.is_lifetime_param())
-                    .count() > 0
+                if let Some(lifetime_str) =
+                    rewrite_lifetime_param(context, shape, bound_generic_params)
                 {
-                    let lifetime_str: String = bound_generic_params
-                        .iter()
-                        .filter_map(|p| match p {
-                            &ast::GenericParam::Lifetime(ref l) => Some(l),
-                            _ => None,
-                        })
-                        .map(|lt| lt.rewrite(context, shape))
-                        .collect::<Option<Vec<_>>>()?
-                        .join(", ");
-
                     // 6 = "for<> ".len()
                     let used_width = lifetime_str.len() + type_str.len() + colon.len() + 6;
                     let ty_shape = shape.offset_left(used_width)?;
@@ -598,21 +586,9 @@ impl Rewrite for ast::TyParam {
 
 impl Rewrite for ast::PolyTraitRef {
     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
-        if self.bound_generic_params
-            .iter()
-            .filter(|p| p.is_lifetime_param())
-            .count() > 0
+        if let Some(lifetime_str) =
+            rewrite_lifetime_param(context, shape, &self.bound_generic_params)
         {
-            let lifetime_str: String = self.bound_generic_params
-                .iter()
-                .filter_map(|p| match p {
-                    &ast::GenericParam::Lifetime(ref l) => Some(l),
-                    _ => None,
-                })
-                .map(|lt| lt.rewrite(context, shape))
-                .collect::<Option<Vec<_>>>()?
-                .join(", ");
-
             // 6 is "for<> ".len()
             let extra_offset = lifetime_str.len() + 6;
             let path_str = self.trait_ref
@@ -762,31 +738,13 @@ fn rewrite_bare_fn(
 ) -> Option<String> {
     let mut result = String::with_capacity(128);
 
-    if bare_fn
-        .generic_params
-        .iter()
-        .filter(|p| p.is_lifetime_param())
-        .count() > 0
+    if let Some(ref lifetime_str) = rewrite_lifetime_param(context, shape, &bare_fn.generic_params)
     {
         result.push_str("for<");
         // 6 = "for<> ".len(), 4 = "for<".
         // This doesn't work out so nicely for mutliline situation with lots of
         // rightward drift. If that is a problem, we could use the list stuff.
-        result.push_str(&bare_fn
-            .generic_params
-            .iter()
-            .filter_map(|p| match p {
-                &ast::GenericParam::Lifetime(ref l) => Some(l),
-                _ => None,
-            })
-            .map(|l| {
-                l.rewrite(
-                    context,
-                    Shape::legacy(shape.width.checked_sub(6)?, shape.indent + 4),
-                )
-            })
-            .collect::<Option<Vec<_>>>()?
-            .join(", "));
+        result.push_str(lifetime_str);
         result.push_str("> ");
     }
 
@@ -841,3 +799,22 @@ pub fn can_be_overflowed_type(context: &RewriteContext, ty: &ast::Ty, len: usize
         _ => false,
     }
 }
+
+/// Returns `None` if there is no `LifetimeDef` in the given generic parameters.
+fn rewrite_lifetime_param(
+    context: &RewriteContext,
+    shape: Shape,
+    generic_params: &[ast::GenericParam],
+) -> Option<String> {
+    let result = generic_params
+        .iter()
+        .filter(|p| p.is_lifetime_param())
+        .map(|lt| lt.rewrite(context, shape))
+        .collect::<Option<Vec<_>>>()?
+        .join(", ");
+    if result.is_empty() {
+        None
+    } else {
+        Some(result)
+    }
+}

tests/system.rs

@@ -24,8 +24,8 @@ use std::path::{Path, PathBuf};
 use std::str::Chars;
 
 use rustfmt::*;
-use rustfmt::filemap::{write_system_newlines, FileMap};
 use rustfmt::config::{Color, Config, ReportTactic};
+use rustfmt::filemap::{write_system_newlines, FileMap};
 use rustfmt::rustfmt_diff::*;
 
 const DIFF_CONTEXT_SIZE: usize = 3;