define all the clippy lints we check in CI in a step

Author: pietroalbini

src/bootstrap/src/core/build_steps/clippy.rs

@@ -102,6 +102,19 @@ impl LintConfig {
             _ => unreachable!("LintConfig can only be called from `clippy` subcommands."),
         }
     }
+
+    fn merge(&self, other: &Self) -> Self {
+        let merged = |self_attr: &[String], other_attr: &[String]| -> Vec<String> {
+            self_attr.iter().cloned().chain(other_attr.iter().cloned()).collect()
+        };
+        // This is written this way to ensure we get a compiler error if we add a new field.
+        Self {
+            allow: merged(&self.allow, &other.allow),
+            warn: merged(&self.warn, &other.warn),
+            deny: merged(&self.deny, &other.deny),
+            forbid: merged(&self.forbid, &other.forbid),
+        }
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -339,3 +352,58 @@ lint_any!(
     Tidy, "src/tools/tidy", "tidy";
     TestFloatParse, "src/etc/test-float-parse", "test-float-parse";
 );
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct CI {
+    target: TargetSelection,
+    config: LintConfig,
+}
+
+impl Step for CI {
+    type Output = ();
+    const DEFAULT: bool = false;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.alias("ci")
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        let config = LintConfig::new(run.builder);
+        run.builder.ensure(CI { target: run.target, config });
+    }
+
+    fn run(self, builder: &Builder<'_>) -> Self::Output {
+        builder.ensure(Bootstrap {
+            target: self.target,
+            config: self.config.merge(&LintConfig {
+                allow: vec![],
+                warn: vec![],
+                deny: vec!["warnings".into()],
+                forbid: vec![],
+            }),
+        });
+        let library_clippy_cfg = LintConfig {
+            allow: vec!["clippy::all".into()],
+            warn: vec![],
+            deny: vec!["clippy::correctness".into()],
+            forbid: vec![],
+        };
+        let compiler_clippy_cfg = LintConfig {
+            allow: vec!["clippy::all".into()],
+            warn: vec![],
+            deny: vec!["clippy::correctness".into(), "clippy::clone_on_ref_ptr".into()],
+            forbid: vec![],
+        };
+
+        builder.ensure(Std {
+            target: self.target,
+            config: self.config.merge(&library_clippy_cfg),
+            crates: vec![],
+        });
+        builder.ensure(Rustc {
+            target: self.target,
+            config: self.config.merge(&compiler_clippy_cfg),
+            crates: vec![],
+        });
+    }
+}

src/bootstrap/src/core/builder/mod.rs

@@ -839,6 +839,7 @@ impl<'a> Builder<'a> {
                 clippy::RustInstaller,
                 clippy::TestFloatParse,
                 clippy::Tidy,
+                clippy::CI,
             ),
             Kind::Check | Kind::Fix => describe!(
                 check::Std,

src/ci/docker/host-x86_64/mingw-check/Dockerfile

@@ -50,9 +50,7 @@ ENV SCRIPT \
            python3 ../x.py check --stage 0 --set build.optimized-compiler-builtins=false core alloc std --target=aarch64-unknown-linux-gnu,i686-pc-windows-msvc,i686-unknown-linux-gnu,x86_64-apple-darwin,x86_64-pc-windows-gnu,x86_64-pc-windows-msvc && \
            /scripts/check-default-config-profiles.sh && \
            python3 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu && \
-           python3 ../x.py clippy bootstrap -Dwarnings && \
-           python3 ../x.py clippy library -Aclippy::all -Dclippy::correctness && \
-           python3 ../x.py clippy compiler -Aclippy::all -Dclippy::correctness -Dclippy::clone_on_ref_ptr && \
+           python3 ../x.py clippy ci && \
            python3 ../x.py build --stage 0 src/tools/build-manifest && \
            python3 ../x.py test --stage 0 src/tools/compiletest && \
            python3 ../x.py test --stage 0 core alloc std test proc_macro && \