Auto merge of #115910 - eduardosm:lang-fns-target-features, r=cjgillot

Prevent using `#[target_feature]` on lang item functions

Fixes https://github.com/rust-lang/rust/issues/109411 and also prevents from using `#[target_feature]` on other `fn` lang items to mitigate the concerns from https://github.com/rust-lang/rust/issues/109411#issuecomment-1477030273.

2 files changed, 26 insertions, 0 deletions

diff --git a/tests/ui/panic-handler/panic-handler-with-target-feature.rs b/tests/ui/panic-handler/panic-handler-with-target-feature.rs
new file mode 100644
index 00000000000..8ea0275d7e9
--- /dev/null
+++ b/tests/ui/panic-handler/panic-handler-with-target-feature.rs
@@ -0,0 +1,15 @@
+// compile-flags:-C panic=abort
+// only-x86_64
+
+#![feature(target_feature_11)]
+#![no_std]
+#![no_main]
+
+use core::panic::PanicInfo;
+
+#[panic_handler]
+#[target_feature(enable = "avx2")]
+//~^ ERROR `panic_impl` language item function is not allowed to have `#[target_feature]`
+fn panic(info: &PanicInfo) -> ! {
+    unimplemented!();
+}
diff --git a/tests/ui/panic-handler/panic-handler-with-target-feature.stderr b/tests/ui/panic-handler/panic-handler-with-target-feature.stderr
new file mode 100644
index 00000000000..4210a4200ae
--- /dev/null
+++ b/tests/ui/panic-handler/panic-handler-with-target-feature.stderr
@@ -0,0 +1,11 @@
+error: `panic_impl` language item function is not allowed to have `#[target_feature]`
+  --> $DIR/panic-handler-with-target-feature.rs:11:1
+   |
+LL | #[target_feature(enable = "avx2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | fn panic(info: &PanicInfo) -> ! {
+   | ------------------------------- `panic_impl` language item function is not allowed to have `#[target_feature]`
+
+error: aborting due to previous error
+