diff --git a/library/coretests/tests/slice.rs b/library/coretests/tests/slice.rs
index 1c5c8a9ebf258..fe356dcc43c7b 100644
--- a/library/coretests/tests/slice.rs
+++ b/library/coretests/tests/slice.rs
@@ -5,8 +5,6 @@ use core::num::NonZero;
 use core::ops::{Range, RangeInclusive};
 use core::slice;
 
-use rand::seq::IndexedRandom;
-
 #[test]
 fn test_position() {
     let b = [1, 2, 3, 5, 5];
@@ -1810,6 +1808,7 @@ fn select_nth_unstable() {
     use core::cmp::Ordering::{Equal, Greater, Less};
 
     use rand::Rng;
+    use rand::seq::IndexedRandom;
 
     let mut rng = crate::test_rng();
 
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index dfcf26cedd65f..3781d020604f3 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -90,7 +90,7 @@ impl Step for CrateBootstrap {
         );
 
         let crate_name = path.rsplit_once('/').unwrap().1;
-        run_cargo_test(cargo, &[], &[], crate_name, crate_name, bootstrap_host, builder);
+        run_cargo_test(cargo, &[], &[], crate_name, bootstrap_host, builder);
     }
 }
 
@@ -140,15 +140,7 @@ You can skip linkcheck with --skip src/tools/linkchecker"
             SourceType::InTree,
             &[],
         );
-        run_cargo_test(
-            cargo,
-            &[],
-            &[],
-            "linkchecker",
-            "linkchecker self tests",
-            bootstrap_host,
-            builder,
-        );
+        run_cargo_test(cargo, &[], &[], "linkchecker self tests", bootstrap_host, builder);
 
         if builder.doc_tests == DocTests::No {
             return;
@@ -331,7 +323,7 @@ impl Step for Cargo {
         );
 
         // NOTE: can't use `run_cargo_test` because we need to overwrite `PATH`
-        let mut cargo = prepare_cargo_test(cargo, &[], &[], "cargo", self.host, builder);
+        let mut cargo = prepare_cargo_test(cargo, &[], &[], self.host, builder);
 
         // Don't run cross-compile tests, we may not have cross-compiled libstd libs
         // available.
@@ -417,7 +409,7 @@ impl Step for RustAnalyzer {
         cargo.env("SKIP_SLOW_TESTS", "1");
 
         cargo.add_rustc_lib_path(builder);
-        run_cargo_test(cargo, &[], &[], "rust-analyzer", "rust-analyzer", host, builder);
+        run_cargo_test(cargo, &[], &[], "rust-analyzer", host, builder);
     }
 }
 
@@ -466,7 +458,7 @@ impl Step for Rustfmt {
 
         cargo.add_rustc_lib_path(builder);
 
-        run_cargo_test(cargo, &[], &[], "rustfmt", "rustfmt", host, builder);
+        run_cargo_test(cargo, &[], &[], "rustfmt", host, builder);
     }
 }
 
@@ -582,7 +574,7 @@ impl Step for Miri {
 
         // We can NOT use `run_cargo_test` since Miri's integration tests do not use the usual test
         // harness and therefore do not understand the flags added by `add_flags_and_try_run_test`.
-        let mut cargo = prepare_cargo_test(cargo, &[], &[], "miri", host, builder);
+        let mut cargo = prepare_cargo_test(cargo, &[], &[], host, builder);
 
         // miri tests need to know about the stage sysroot
         cargo.env("MIRI_SYSROOT", &miri_sysroot);
@@ -730,7 +722,7 @@ impl Step for CompiletestTest {
             &[],
         );
         cargo.allow_features("test");
-        run_cargo_test(cargo, &[], &[], "compiletest", "compiletest self test", host, builder);
+        run_cargo_test(cargo, &[], &[], "compiletest self test", host, builder);
     }
 }
 
@@ -791,7 +783,7 @@ impl Step for Clippy {
         cargo.env("HOST_LIBS", host_libs);
 
         cargo.add_rustc_lib_path(builder);
-        let cargo = prepare_cargo_test(cargo, &[], &[], "clippy", host, builder);
+        let cargo = prepare_cargo_test(cargo, &[], &[], host, builder);
 
         let _guard = builder.msg_sysroot_tool(Kind::Test, compiler.stage, "clippy", host, host);
 
@@ -1318,15 +1310,7 @@ impl Step for CrateRunMakeSupport {
             &[],
         );
         cargo.allow_features("test");
-        run_cargo_test(
-            cargo,
-            &[],
-            &[],
-            "run-make-support",
-            "run-make-support self test",
-            host,
-            builder,
-        );
+        run_cargo_test(cargo, &[], &[], "run-make-support self test", host, builder);
     }
 }
 
@@ -1363,7 +1347,7 @@ impl Step for CrateBuildHelper {
             &[],
         );
         cargo.allow_features("test");
-        run_cargo_test(cargo, &[], &[], "build_helper", "build_helper self test", host, builder);
+        run_cargo_test(cargo, &[], &[], "build_helper self test", host, builder);
     }
 }
 
@@ -2569,13 +2553,12 @@ fn run_cargo_test<'a>(
     cargo: builder::Cargo,
     libtest_args: &[&str],
     crates: &[String],
-    primary_crate: &str,
     description: impl Into<Option<&'a str>>,
     target: TargetSelection,
     builder: &Builder<'_>,
 ) -> bool {
     let compiler = cargo.compiler();
-    let mut cargo = prepare_cargo_test(cargo, libtest_args, crates, primary_crate, target, builder);
+    let mut cargo = prepare_cargo_test(cargo, libtest_args, crates, target, builder);
     let _time = helpers::timeit(builder);
     let _group = description.into().and_then(|what| {
         builder.msg_sysroot_tool(Kind::Test, compiler.stage, what, compiler.host, target)
@@ -2599,7 +2582,6 @@ fn prepare_cargo_test(
     cargo: builder::Cargo,
     libtest_args: &[&str],
     crates: &[String],
-    primary_crate: &str,
     target: TargetSelection,
     builder: &Builder<'_>,
 ) -> BootstrapCommand {
@@ -2629,13 +2611,6 @@ fn prepare_cargo_test(
             cargo.arg("--doc");
         }
         DocTests::No => {
-            let krate = &builder
-                .crates
-                .get(primary_crate)
-                .unwrap_or_else(|| panic!("missing crate {primary_crate}"));
-            if krate.has_lib {
-                cargo.arg("--lib");
-            }
             cargo.args(["--bins", "--examples", "--tests", "--benches"]);
         }
         DocTests::Yes => {}
@@ -2810,15 +2785,15 @@ impl Step for Crate {
             _ => panic!("can only test libraries"),
         };
 
-        run_cargo_test(
-            cargo,
-            &[],
-            &self.crates,
-            &self.crates[0],
-            &*crate_description(&self.crates),
-            target,
-            builder,
-        );
+        let mut crates = self.crates.clone();
+        // The core crate can't directly be tested. We could silently
+        // ignore it, but adding it's own test crate is less confusing
+        // for users. We still keep core itself for doctests.
+        if crates.iter().any(|crate_| crate_ == "core") {
+            crates.push("coretests".to_owned());
+        }
+
+        run_cargo_test(cargo, &[], &crates, &*crate_description(&self.crates), target, builder);
     }
 }
 
@@ -2911,15 +2886,7 @@ impl Step for CrateRustdoc {
         dylib_path.insert(0, PathBuf::from(&*libdir));
         cargo.env(dylib_path_var(), env::join_paths(&dylib_path).unwrap());
 
-        run_cargo_test(
-            cargo,
-            &[],
-            &["rustdoc:0.0.0".to_string()],
-            "rustdoc",
-            "rustdoc",
-            target,
-            builder,
-        );
+        run_cargo_test(cargo, &[], &["rustdoc:0.0.0".to_string()], "rustdoc", target, builder);
     }
 }
 
@@ -2976,7 +2943,6 @@ impl Step for CrateRustdocJsonTypes {
             libtest_args,
             &["rustdoc-json-types".to_string()],
             "rustdoc-json-types",
-            "rustdoc-json-types",
             target,
             builder,
         );
@@ -3156,7 +3122,7 @@ impl Step for Bootstrap {
 
         // bootstrap tests are racy on directory creation so just run them one at a time.
         // Since there's not many this shouldn't be a problem.
-        run_cargo_test(cargo, &["--test-threads=1"], &[], "bootstrap", None, host, builder);
+        run_cargo_test(cargo, &["--test-threads=1"], &[], None, host, builder);
     }
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
@@ -3281,7 +3247,7 @@ impl Step for RustInstaller {
             bootstrap_host,
             bootstrap_host,
         );
-        run_cargo_test(cargo, &[], &[], "installer", None, bootstrap_host, builder);
+        run_cargo_test(cargo, &[], &[], None, bootstrap_host, builder);
 
         // We currently don't support running the test.sh script outside linux(?) environments.
         // Eventually this should likely migrate to #[test]s in rust-installer proper rather than a
@@ -3672,7 +3638,7 @@ impl Step for TestFloatParse {
             &[],
         );
 
-        run_cargo_test(cargo_test, &[], &[], crate_name, crate_name, bootstrap_host, builder);
+        run_cargo_test(cargo_test, &[], &[], crate_name, bootstrap_host, builder);
 
         // Run the actual parse tests.
         let mut cargo_run = tool::prepare_tool_cargo(
diff --git a/src/bootstrap/src/core/metadata.rs b/src/bootstrap/src/core/metadata.rs
index 01cbf6629408d..2706aba5ffc8d 100644
--- a/src/bootstrap/src/core/metadata.rs
+++ b/src/bootstrap/src/core/metadata.rs
@@ -28,7 +28,6 @@ struct Package {
     source: Option<String>,
     manifest_path: String,
     dependencies: Vec<Dependency>,
-    targets: Vec<Target>,
     features: BTreeMap<String, Vec<String>>,
 }
 
@@ -40,11 +39,6 @@ struct Dependency {
     source: Option<String>,
 }
 
-#[derive(Debug, Deserialize)]
-struct Target {
-    kind: Vec<String>,
-}
-
 /// Collects and stores package metadata of each workspace members into `build`,
 /// by executing `cargo metadata` commands.
 pub fn build(build: &mut Build) {
@@ -59,12 +53,10 @@ pub fn build(build: &mut Build) {
                 .filter(|dep| dep.source.is_none())
                 .map(|dep| dep.name)
                 .collect();
-            let has_lib = package.targets.iter().any(|t| t.kind.iter().any(|k| k == "lib"));
             let krate = Crate {
                 name: name.clone(),
                 deps,
                 path,
-                has_lib,
                 features: package.features.keys().cloned().collect(),
             };
             let relative_path = krate.local_path(build);
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 351e67f6702d1..4ea711c1325e8 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -185,7 +185,6 @@ struct Crate {
     name: String,
     deps: HashSet<String>,
     path: PathBuf,
-    has_lib: bool,
     features: Vec<String>,
 }