initial working version of cargo fix --clippy

src/bin/cargo/commands/fix.rs

@@ -72,6 +72,11 @@ pub fn cli() -> App {
                 .long("allow-staged")
                 .help("Fix code even if the working directory has staged changes"),
         )
+        .arg(
+            Arg::with_name("clippy")
+                .long("clippy")
+                .help("(unstable) get fix suggestions from clippy instead of check"),
+        )
         .after_help(
             "\
 This Cargo subcommand will automatically take rustc's suggestions from
@@ -125,6 +130,15 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
     // code as we can.
     let mut opts = args.compile_options(config, mode, Some(&ws))?;
 
+    let use_clippy = args.is_present("clippy");
+
+    if use_clippy && !config.cli_unstable().unstable_options {
+        return Err(failure::format_err!(
+            "`cargo fix --clippy` is unstable, pass `-Z unstable-options` to enable it"
+        )
+        .into());
+    }
+
     if let CompileFilter::Default { .. } = opts.filter {
         opts.filter = CompileFilter::Only {
             all_targets: true,
@@ -146,6 +160,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
             allow_no_vcs: args.is_present("allow-no-vcs"),
             allow_staged: args.is_present("allow-staged"),
             broken_code: args.is_present("broken-code"),
+            use_clippy
         },
     )?;
     Ok(())

src/cargo/ops/fix.rs

@@ -63,6 +63,7 @@ const BROKEN_CODE_ENV: &str = "__CARGO_FIX_BROKEN_CODE";
 const PREPARE_FOR_ENV: &str = "__CARGO_FIX_PREPARE_FOR";
 const EDITION_ENV: &str = "__CARGO_FIX_EDITION";
 const IDIOMS_ENV: &str = "__CARGO_FIX_IDIOMS";
+const CLIPPY_FIX_ENV: &str = "__CARGO_FIX_CLIPPY_PLZ";
 
 pub struct FixOptions<'a> {
     pub edition: bool,
@@ -73,6 +74,7 @@ pub struct FixOptions<'a> {
     pub allow_no_vcs: bool,
     pub allow_staged: bool,
     pub broken_code: bool,
+    pub use_clippy: bool,
 }
 
 pub fn fix(ws: &Workspace<'_>, opts: &mut FixOptions<'_>) -> CargoResult<()> {
@@ -99,6 +101,10 @@ pub fn fix(ws: &Workspace<'_>, opts: &mut FixOptions<'_>) -> CargoResult<()> {
         wrapper.env(IDIOMS_ENV, "1");
     }
 
+    if opts.use_clippy {
+        wrapper.env(CLIPPY_FIX_ENV, "1");
+    }
+
     *opts
         .compile_opts
         .build_config
@@ -582,7 +588,11 @@ impl Default for PrepareFor {
 impl FixArgs {
     fn get() -> FixArgs {
         let mut ret = FixArgs::default();
-        ret.rustc = env::args_os().nth(1).map(PathBuf::from);
+        if env::var(CLIPPY_FIX_ENV).is_ok() {
+            ret.rustc = Some(PathBuf::from("clippy-driver"));
+        } else {
+            ret.rustc = env::args_os().nth(1).map(PathBuf::from);
+        }
         for arg in env::args_os().skip(2) {
             let path = PathBuf::from(arg);
             if path.extension().and_then(|s| s.to_str()) == Some("rs") && path.exists() {