Enforce in bootstrap that clippy must have stage at least 1

src/bootstrap/src/core/build_steps/check.rs

@@ -30,10 +30,6 @@ pub struct Std {
 
 impl Std {
  const CRATE_OR_DEPS: &[&str] = &["sysroot", "coretests", "alloctests"];
-
- pub fn new(build_compiler: Compiler, target: TargetSelection) -> Self {
- Self { build_compiler, target, crates: vec![] }
- }
 }
 
 impl Step for Std {
@@ -168,12 +164,8 @@ pub struct Rustc {
 }
 
 impl Rustc {
- pub fn new(builder: &Builder<'_>, build_compiler: Compiler, target: TargetSelection) -> Self {
- let crates = builder
- .in_tree_crates("rustc-main", Some(target))
- .into_iter()
- .map(|krate| krate.name.to_string())
- .collect();
+ pub fn new(builder: &Builder<'_>, target: TargetSelection, crates: Vec<String>) -> Self {
+ let build_compiler = prepare_compiler_for_check(builder, target, Mode::Rustc);
  Self { build_compiler, target, crates }
  }
 }
@@ -189,11 +181,7 @@ impl Step for Rustc {
 
  fn make_run(run: RunConfig<'_>) {
  let crates = run.make_run_crates(Alias::Compiler);
- run.builder.ensure(Rustc {
- target: run.target,
- build_compiler: prepare_compiler_for_check(run.builder, run.target, Mode::Rustc),
- crates,
- });
+ run.builder.ensure(Rustc::new(run.builder, run.target, crates));
  }
 
  /// Check the compiler.
@@ -207,15 +195,6 @@ impl Step for Rustc {
  let build_compiler = self.build_compiler;
  let target = self.target;
 
- // Build host std for compiling build scripts
- builder.std(build_compiler, build_compiler.host);
-
- // Build target std so that the checked rustc can link to it during the check
- // FIXME: maybe we can a way to only do a check of std here?
- // But for that we would have to copy the stdlib rmetas to the sysroot of the build
- // compiler, which conflicts with std rlibs, if we also build std.
- builder.std(build_compiler, target);
-
  let mut cargo = builder::Cargo::new(
  builder,
  build_compiler,
@@ -258,7 +237,7 @@ impl Step for Rustc {
 }
 
 /// Prepares a compiler that will check something with the given `mode`.
-fn prepare_compiler_for_check(
+pub fn prepare_compiler_for_check(
  builder: &Builder<'_>,
  target: TargetSelection,
  mode: Mode,
@@ -289,11 +268,13 @@ fn prepare_compiler_for_check(
  build_compiler
  }
  Mode::ToolRustc | Mode::Codegen => {
- // FIXME: this is a hack, see description of Mode::Rustc below
- let stage = if host == target { builder.top_stage - 1 } else { builder.top_stage };
- // When checking tool stage N, we check it with compiler stage N-1
- let build_compiler = builder.compiler(stage, host);
- builder.ensure(Rustc::new(builder, build_compiler, target));
+ // Check Rustc to produce the required rmeta artifacts for rustc_private, and then
+ // return the build compiler that was used to check rustc.
+ // We do not need to check examples/tests/etc. of Rustc for rustc_private, so we pass
+ // an empty set of crates, which will avoid using `cargo -p`.
+ let check = Rustc::new(builder, target, vec![]);
+ let build_compiler = check.build_compiler;
+ builder.ensure(check);
  build_compiler
  }
  Mode::Rustc => {
@@ -305,7 +286,18 @@ fn prepare_compiler_for_check(
  // FIXME: remove this and either fix cross-compilation check on stage 2 (which has a
  // myriad of other problems) or disable cross-checking on stage 1.
  let stage = if host == target { builder.top_stage - 1 } else { builder.top_stage };
- builder.compiler(stage, host)
+ let build_compiler = builder.compiler(stage, host);
+
+ // Build host std for compiling build scripts
+ builder.std(build_compiler, build_compiler.host);
+
+ // Build target std so that the checked rustc can link to it during the check
+ // FIXME: maybe we can a way to only do a check of std here?
+ // But for that we would have to copy the stdlib rmetas to the sysroot of the build
+ // compiler, which conflicts with std rlibs, if we also build std.
+ builder.std(build_compiler, target);
+
+ build_compiler
  }
  Mode::Std => {
  // When checking std stage N, we want to do it with the stage N compiler