Implement x.py test src/tools/clippy --bless

- Add clippy_dev to the rust workspace

  Before, it would give an error that it wasn't either included or
  excluded from the workspace:

  ```
  error: current package believes it's in a workspace when it's not:
  current:   /home/joshua/rustc/src/tools/clippy/clippy_dev/Cargo.toml
  workspace: /home/joshua/rustc/Cargo.toml

  this may be fixable by adding `src/tools/clippy/clippy_dev` to the `workspace.members` array of the manifest located at: /home/joshua/rustc/Cargo.toml
  Alternatively, to keep it out of the workspace, add the package to the `workspace.exclude` array, or add an empty `[workspace]` table to the package's manifest.
  ```

- Change clippy's copy of compiletest not to special-case
  rust-lang/rust. Using OUT_DIR confused `clippy_dev` and it couldn't find
  the test outputs. This is one of the reasons why `cargo dev bless` used
  to silently do nothing (the others were that `CARGO_TARGET_DIR` and
  `PROFILE` weren't set appropriately).

- Run clippy_dev on test failure

I tested this by removing a couple lines from a stderr file, and they
were correctly replaced.

- Fix clippy_dev warnings

Cargo.lock

@@ -599,6 +599,19 @@ dependencies = [
 name = "clippy-mini-macro-test"
 version = "0.2.0"
 
+[[package]]
+name = "clippy_dev"
+version = "0.0.1"
+dependencies = [
+ "bytecount",
+ "clap",
+ "itertools 0.9.0",
+ "opener",
+ "regex",
+ "shell-escape",
+ "walkdir",
+]
+
 [[package]]
 name = "clippy_lints"
 version = "0.1.53"

Cargo.toml

@@ -7,6 +7,7 @@ members = [
   "src/rustdoc-json-types",
   "src/tools/cargotest",
   "src/tools/clippy",
+  "src/tools/clippy/clippy_dev",
   "src/tools/compiletest",
   "src/tools/error_index_generator",
   "src/tools/linkchecker",

src/bootstrap/builder.rs

@@ -1627,6 +1627,11 @@ impl Cargo {
     pub fn add_rustc_lib_path(&mut self, builder: &Builder<'_>, compiler: Compiler) {
         builder.add_rustc_lib_path(compiler, &mut self.command);
     }
+
+    pub fn current_dir(&mut self, dir: &Path) -> &mut Cargo {
+        self.command.current_dir(dir);
+        self
+    }
 }
 
 impl From<Cargo> for Command {

src/bootstrap/test.rs

@@ -632,6 +632,26 @@ impl Step for Clippy {
 
         cargo.add_rustc_lib_path(builder, compiler);
 
+        if builder.try_run(&mut cargo.into()) {
+            // The tests succeeded; nothing to do.
+            return;
+        }
+
+        if !builder.config.cmd.bless() {
+            std::process::exit(1);
+        }
+
+        let mut cargo = builder.cargo(compiler, Mode::ToolRustc, SourceType::InTree, host, "run");
+        cargo.arg("-p").arg("clippy_dev");
+        // clippy_dev gets confused if it can't find `clippy/Cargo.toml`
+        cargo.current_dir(&builder.src.join("src").join("tools").join("clippy"));
+        if builder.config.rust_optimize {
+            cargo.env("PROFILE", "release");
+        } else {
+            cargo.env("PROFILE", "debug");
+        }
+        cargo.arg("--");
+        cargo.arg("bless");
         builder.run(&mut cargo.into());
     }
 }

src/tools/clippy/clippy_dev/src/new_lint.rs

@@ -44,7 +44,7 @@ pub fn create(pass: Option<&str>, lint_name: Option<&str>, category: Option<&str
     create_test(&lint).context("Unable to create a test for the new lint")
 }
 
-fn create_lint(lint: &LintData) -> io::Result<()> {
+fn create_lint(lint: &LintData<'_>) -> io::Result<()> {
     let (pass_type, pass_lifetimes, pass_import, context_import) = match lint.pass {
         "early" => ("EarlyLintPass", "", "use rustc_ast::ast::*;", "EarlyContext"),
         "late" => ("LateLintPass", "<'_>", "use rustc_hir::*;", "LateContext"),
@@ -68,7 +68,7 @@ fn create_lint(lint: &LintData) -> io::Result<()> {
     write_file(lint.project_root.join(&lint_path), lint_contents.as_bytes())
 }
 
-fn create_test(lint: &LintData) -> io::Result<()> {
+fn create_test(lint: &LintData<'_>) -> io::Result<()> {
     fn create_project_layout<P: Into<PathBuf>>(lint_name: &str, location: P, case: &str, hint: &str) -> io::Result<()> {
         let mut path = location.into().join(case);
         fs::create_dir(&path)?;

src/tools/clippy/tests/compile-test.rs

@@ -83,14 +83,7 @@ fn default_config() -> compiletest::Config {
         third_party_crates(),
     ));
 
-    config.build_base = if cargo::is_rustc_test_suite() {
-        // This make the stderr files go to clippy OUT_DIR on rustc repo build dir
-        let mut path = PathBuf::from(env!("OUT_DIR"));
-        path.push("test_build_base");
-        path
-    } else {
-        host_lib().join("test_build_base")
-    };
+    config.build_base = host_lib().join("test_build_base");
     config.rustc_path = clippy_driver_path();
     config
 }