clippy: make tests work in stage 1

src/bootstrap/src/core/build_steps/test.rs

@@ -739,7 +739,6 @@ impl Step for CompiletestTest {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Clippy {
-    stage: u32,
     host: TargetSelection,
 }
 
@@ -753,33 +752,23 @@ impl Step for Clippy {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        // If stage is explicitly set or not lower than 2, keep it. Otherwise, make sure it's at least 2
-        // as tests for this step don't work with a lower stage.
-        let stage = if run.builder.config.is_explicit_stage() || run.builder.top_stage >= 2 {
-            run.builder.top_stage
-        } else {
-            2
-        };
-
-        run.builder.ensure(Clippy { stage, host: run.target });
+        run.builder.ensure(Clippy { host: run.target });
     }
 
     /// Runs `cargo test` for clippy.
     fn run(self, builder: &Builder<'_>) {
-        let stage = self.stage;
+        let stage = builder.top_stage;
         let host = self.host;
-        let compiler = builder.compiler(stage, host);
-
-        if stage < 2 {
-            eprintln!("WARNING: clippy tests on stage {stage} may not behave well.");
-            eprintln!("HELP: consider using stage 2");
-        }
+        // We need to carefully distinguish the compiler that builds clippy, and the compiler
+        // that is linked into the clippy being tested. `target_compiler` is the latter,
+        // and it must also be used by clippy's test runner to build tests and their dependencies.
+        let target_compiler = builder.compiler(stage, host);
 
-        let tool_result = builder.ensure(tool::Clippy { compiler, target: self.host });
-        let compiler = tool_result.build_compiler;
+        let tool_result = builder.ensure(tool::Clippy { compiler: target_compiler, target: host });
+        let tool_compiler = tool_result.build_compiler;
         let mut cargo = tool::prepare_tool_cargo(
             builder,
-            compiler,
+            tool_compiler,
             Mode::ToolRustc,
             host,
             Kind::Test,
@@ -788,11 +777,17 @@ impl Step for Clippy {
             &[],
         );
 
-        cargo.env("RUSTC_TEST_SUITE", builder.rustc(compiler));
-        cargo.env("RUSTC_LIB_PATH", builder.rustc_libdir(compiler));
-        let host_libs = builder.stage_out(compiler, Mode::ToolRustc).join(builder.cargo_dir());
+        cargo.env("RUSTC_TEST_SUITE", builder.rustc(tool_compiler));
+        cargo.env("RUSTC_LIB_PATH", builder.rustc_libdir(tool_compiler));
+        let host_libs = builder.stage_out(tool_compiler, Mode::ToolRustc).join(builder.cargo_dir());
         cargo.env("HOST_LIBS", host_libs);
 
+        // Build the standard library that the tests can use.
+        builder.std(target_compiler, host);
+        cargo.env("TEST_SYSROOT", builder.sysroot(target_compiler));
+        cargo.env("TEST_RUSTC", builder.rustc(target_compiler));
+        cargo.env("TEST_RUSTC_LIB", builder.rustc_libdir(target_compiler));
+
         // Collect paths of tests to run
         'partially_test: {
             let paths = &builder.config.paths[..];
@@ -813,7 +808,8 @@ impl Step for Clippy {
         cargo.add_rustc_lib_path(builder);
         let cargo = prepare_cargo_test(cargo, &[], &[], host, builder);
 
-        let _guard = builder.msg_sysroot_tool(Kind::Test, compiler.stage, "clippy", host, host);
+        let _guard =
+            builder.msg_sysroot_tool(Kind::Test, tool_compiler.stage, "clippy", host, host);
 
         // Clippy reports errors if it blessed the outputs
         if cargo.allow_failure().run(builder) {

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

@@ -151,7 +151,31 @@ impl TestContext {
         defaults.set_custom(
             "dependencies",
             DependencyBuilder {
-                program: CommandBuilder::cargo(),
+                program: {
+                    let mut p = CommandBuilder::cargo();
+                    // If we run in bootstrap, we need to use the right compiler for building the
+                    // tests -- not the compiler that built clippy, but the compiler that got linked
+                    // into clippy. Just invoking TEST_RUSTC does not work because LD_LIBRARY_PATH
+                    // is set in a way that makes it pick the wrong sysroot. Sadly due to
+                    // <https://github.com/rust-lang/cargo/issues/4423> we cannot use RUSTFLAGS to
+                    // set `--sysroot`, so we need to use bootstrap's rustc wrapper. That wrapper
+                    // however has some staging logic that is hurting us here, so to work around
+                    // that we set both the "real" and "staging" rustc to TEST_RUSTC, including the
+                    // associated library paths.
+                    if let Some(rustc) = option_env!("TEST_RUSTC") {
+                        let libdir = option_env!("TEST_RUSTC_LIB").unwrap();
+                        let sysroot = option_env!("TEST_SYSROOT").unwrap();
+                        p.envs.push(("RUSTC_REAL".into(), Some(rustc.into())));
+                        p.envs.push(("RUSTC_REAL_LIBDIR".into(), Some(libdir.into())));
+                        p.envs.push(("RUSTC_SNAPSHOT".into(), Some(rustc.into())));
+                        p.envs.push(("RUSTC_SNAPSHOT_LIBDIR".into(), Some(libdir.into())));
+                        p.envs.push((
+                            "RUSTC_SYSROOT".into(),
+                            Some(sysroot.into()),
+                        ));
+                    }
+                    p
+                },
                 crate_manifest_path: Path::new("clippy_test_deps").join("Cargo.toml"),
                 build_std: None,
                 bless_lockfile: self.args.bless,
@@ -192,6 +216,9 @@ impl TestContext {
             let dep = format!("-Ldependency={}", Path::new(host_libs).join("deps").display());
             config.program.args.push(dep.into());
         }
+        if let Some(sysroot) = option_env!("TEST_SYSROOT") {
+            config.program.args.push(format!("--sysroot={sysroot}").into());
+        }
 
         config.program.program = profile_path.join(if cfg!(windows) {
             "clippy-driver.exe"

src/tools/clippy/tests/ui/auxiliary/proc_macro_derive.rs

@@ -16,7 +16,7 @@ pub fn derive(_: TokenStream) -> TokenStream {
     let output = quote! {
         // Should not trigger `useless_attribute`
         #[allow(dead_code)]
-        extern crate rustc_middle;
+        extern crate core;
     };
     output
 }

src/tools/clippy/tests/ui/iter_over_hash_type.rs

@@ -3,15 +3,18 @@
 #![warn(clippy::iter_over_hash_type)]
 use std::collections::{HashMap, HashSet};
 
-extern crate rustc_data_structures;
-
 extern crate proc_macros;
 
+// Ensure it also works via type aliases (this isn't really the Fx hasher but that does not matter).
+type FxBuildHasher = std::collections::hash_map::RandomState;
+type FxHashMap<K, V> = HashMap<K, V, FxBuildHasher>;
+type FxHashSet<K> = HashSet<K, FxBuildHasher>;
+
 fn main() {
     let mut hash_set = HashSet::<i32>::new();
     let mut hash_map = HashMap::<i32, i32>::new();
-    let mut fx_hash_map = rustc_data_structures::fx::FxHashMap::<i32, i32>::default();
-    let mut fx_hash_set = rustc_data_structures::fx::FxHashMap::<i32, i32>::default();
+    let mut fx_hash_map = FxHashMap::<i32, i32>::default();
+    let mut fx_hash_set = FxHashSet::<i32>::default();
     let vec = Vec::<i32>::new();
 
     // test hashset

src/tools/clippy/tests/ui/iter_over_hash_type.stderr

@@ -1,5 +1,5 @@
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:18:5
+  --> tests/ui/iter_over_hash_type.rs:21:5
    |
 LL | /     for x in &hash_set {
 LL | |
@@ -11,7 +11,7 @@ LL | |     }
    = help: to override `-D warnings` add `#[allow(clippy::iter_over_hash_type)]`
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:22:5
+  --> tests/ui/iter_over_hash_type.rs:25:5
    |
 LL | /     for x in hash_set.iter() {
 LL | |
@@ -20,7 +20,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:26:5
+  --> tests/ui/iter_over_hash_type.rs:29:5
    |
 LL | /     for x in hash_set.clone() {
 LL | |
@@ -29,7 +29,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:30:5
+  --> tests/ui/iter_over_hash_type.rs:33:5
    |
 LL | /     for x in hash_set.drain() {
 LL | |
@@ -38,7 +38,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:36:5
+  --> tests/ui/iter_over_hash_type.rs:39:5
    |
 LL | /     for (x, y) in &hash_map {
 LL | |
@@ -47,7 +47,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:40:5
+  --> tests/ui/iter_over_hash_type.rs:43:5
    |
 LL | /     for x in hash_map.keys() {
 LL | |
@@ -56,7 +56,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:44:5
+  --> tests/ui/iter_over_hash_type.rs:47:5
    |
 LL | /     for x in hash_map.values() {
 LL | |
@@ -65,7 +65,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:48:5
+  --> tests/ui/iter_over_hash_type.rs:51:5
    |
 LL | /     for x in hash_map.values_mut() {
 LL | |
@@ -74,7 +74,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:52:5
+  --> tests/ui/iter_over_hash_type.rs:55:5
    |
 LL | /     for x in hash_map.iter() {
 LL | |
@@ -83,7 +83,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:56:5
+  --> tests/ui/iter_over_hash_type.rs:59:5
    |
 LL | /     for x in hash_map.clone() {
 LL | |
@@ -92,7 +92,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:60:5
+  --> tests/ui/iter_over_hash_type.rs:63:5
    |
 LL | /     for x in hash_map.drain() {
 LL | |
@@ -101,7 +101,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:66:5
+  --> tests/ui/iter_over_hash_type.rs:69:5
    |
 LL | /     for x in fx_hash_set {
 LL | |
@@ -110,7 +110,7 @@ LL | |     }
    | |_____^
 
 error: iteration over unordered hash-based type
-  --> tests/ui/iter_over_hash_type.rs:70:5
+  --> tests/ui/iter_over_hash_type.rs:73:5
    |
 LL | /     for x in fx_hash_map {
 LL | |

src/tools/clippy/tests/ui/useless_attribute.fixed

@@ -13,7 +13,7 @@
 #[allow(unused_imports)]
 #[allow(unused_extern_crates)]
 #[macro_use]
-extern crate rustc_middle;
+extern crate regex as regex_crate;
 
 #[macro_use]
 extern crate proc_macro_derive;

src/tools/clippy/tests/ui/useless_attribute.rs

@@ -13,7 +13,7 @@
 #[allow(unused_imports)]
 #[allow(unused_extern_crates)]
 #[macro_use]
-extern crate rustc_middle;
+extern crate regex as regex_crate;
 
 #[macro_use]
 extern crate proc_macro_derive;