Stabilize cargo clippy --fix

This has been unstable since it was first introduced in
rust-lang#5363. In that time, I have
been using it successfully in nightly without issues. I don't think
there are any blocking issues now that RUSTC_WORKSPACE_WRAPPER is
stabilized, so this can be stabilized.

Author: jyn514

.github/workflows/clippy.yml

@@ -71,7 +71,7 @@ jobs:
       working-directory: clippy_workspace_tests
 
     - name: Test cargo-clippy --fix
-      run: ../target/debug/cargo-clippy clippy --fix -Zunstable-options
+      run: ../target/debug/cargo-clippy clippy --fix
       working-directory: clippy_workspace_tests
 
     - name: Test clippy-driver

.github/workflows/clippy_bors.yml

@@ -134,7 +134,7 @@ jobs:
       working-directory: clippy_workspace_tests
 
     - name: Test cargo-clippy --fix
-      run: ../target/debug/cargo-clippy clippy --fix -Zunstable-options
+      run: ../target/debug/cargo-clippy clippy --fix
       working-directory: clippy_workspace_tests
 
     - name: Test clippy-driver

README.md

@@ -75,11 +75,10 @@ cargo clippy
 
 #### Automatically applying Clippy suggestions
 
-Clippy can automatically apply some lint suggestions.
-Note that this is still experimental and only supported on the nightly channel:
+Clippy can automatically apply some lint suggestions, just like the compiler.
 
 ```terminal
-cargo clippy --fix -Z unstable-options
+cargo clippy --fix
 ```
 
 #### Workspaces

lintcheck/README.md

@@ -69,7 +69,7 @@ is checked.
 is explicitly specified in the options.
 
 ### Fix mode
-You can run `./lintcheck/target/debug/lintcheck --fix` which will run Clippy with `-Zunstable-options --fix` and
+You can run `./lintcheck/target/debug/lintcheck --fix` which will run Clippy with `--fix` and
 print a warning if Clippys suggestions fail to apply (if the resulting code does not build).  
 This lets us spot bad suggestions or false positives automatically in some cases.  
 

lintcheck/src/main.rs

@@ -260,14 +260,7 @@ impl Crate {
         let shared_target_dir = clippy_project_root().join("target/lintcheck/shared_target_dir");
 
         let mut args = if fix {
-            vec![
-                "-Zunstable-options",
-                "--fix",
-                "-Zunstable-options",
-                "--allow-no-vcs",
-                "--",
-                "--cap-lints=warn",
-            ]
+            vec!["--fix", "--allow-no-vcs", "--", "--cap-lints=warn"]
         } else {
             vec!["--", "--message-format=json", "--", "--cap-lints=warn"]
         };

src/main.rs

@@ -70,7 +70,6 @@ impl ClippyCmd {
         I: Iterator<Item = String>,
     {
         let mut cargo_subcommand = "check";
-        let mut unstable_options = false;
         let mut args = vec![];
 
         for arg in old_args.by_ref() {
@@ -80,18 +79,12 @@ impl ClippyCmd {
                     continue;
                 },
                 "--" => break,
-                // Cover -Zunstable-options and -Z unstable-options
-                s if s.ends_with("unstable-options") => unstable_options = true,
                 _ => {},
             }
 
             args.push(arg);
         }
 
-        if cargo_subcommand == "fix" && !unstable_options {
-            panic!("Usage of `--fix` requires `-Z unstable-options`");
-        }
-
         let mut clippy_args: Vec<String> = old_args.collect();
         if cargo_subcommand == "fix" && !clippy_args.iter().any(|arg| arg == "--no-deps") {
             clippy_args.push("--no-deps".into());
@@ -176,34 +169,23 @@ mod tests {
     use super::ClippyCmd;
 
     #[test]
-    #[should_panic]
-    fn fix_without_unstable() {
+    fn fix() {
         let args = "cargo clippy --fix".split_whitespace().map(ToString::to_string);
-        ClippyCmd::new(args);
-    }
-
-    #[test]
-    fn fix_unstable() {
-        let args = "cargo clippy --fix -Zunstable-options"
-            .split_whitespace()
-            .map(ToString::to_string);
         let cmd = ClippyCmd::new(args);
         assert_eq!("fix", cmd.cargo_subcommand);
-        assert!(cmd.args.iter().any(|arg| arg.ends_with("unstable-options")));
+        assert!(!cmd.args.iter().any(|arg| arg.ends_with("unstable-options")));
     }
 
     #[test]
     fn fix_implies_no_deps() {
-        let args = "cargo clippy --fix -Zunstable-options"
-            .split_whitespace()
-            .map(ToString::to_string);
+        let args = "cargo clippy --fix".split_whitespace().map(ToString::to_string);
         let cmd = ClippyCmd::new(args);
         assert!(cmd.clippy_args.iter().any(|arg| arg == "--no-deps"));
     }
 
     #[test]
     fn no_deps_not_duplicated_with_fix() {
-        let args = "cargo clippy --fix -Zunstable-options -- --no-deps"
+        let args = "cargo clippy --fix -- --no-deps"
             .split_whitespace()
             .map(ToString::to_string);
         let cmd = ClippyCmd::new(args);