fix: Handle newstyle rustc_intrinsic safety correctly

crates/hir-ty/src/utils.rs

@@ -270,25 +270,22 @@ pub fn is_fn_unsafe_to_call(db: &dyn HirDatabase, func: FunctionId) -> bool {
         return true;
     }
 
-    let is_intrinsic = db.attrs(func.into()).by_key(&sym::rustc_intrinsic).exists()
-        || data.abi.as_ref() == Some(&sym::rust_dash_intrinsic);
-
     let loc = func.lookup(db.upcast());
     match loc.container {
         hir_def::ItemContainerId::ExternBlockId(block) => {
-            if is_intrinsic || {
-                let id = block.lookup(db.upcast()).id;
-                id.item_tree(db.upcast())[id.value].abi.as_ref() == Some(&sym::rust_dash_intrinsic)
-            } {
-                // Intrinsics are unsafe unless they have the rustc_safe_intrinsic attribute
+            let id = block.lookup(db.upcast()).id;
+            let is_intrinsic_block =
+                id.item_tree(db.upcast())[id.value].abi.as_ref() == Some(&sym::rust_dash_intrinsic);
+            if is_intrinsic_block {
+                // legacy intrinsics
+                // extern "rust-intrinsic" intrinsics are unsafe unless they have the rustc_safe_intrinsic attribute
                 !db.attrs(func.into()).by_key(&sym::rustc_safe_intrinsic).exists()
             } else {
                 // Function in an `extern` block are always unsafe to call, except when
                 // it is marked as `safe`.
                 !data.is_safe()
             }
         }
-        _ if is_intrinsic => !db.attrs(func.into()).by_key(&sym::rustc_safe_intrinsic).exists(),
         _ => false,
     }
 }

crates/ide-diagnostics/src/handlers/missing_unsafe.rs

@@ -237,6 +237,24 @@ fn main() {
     fn no_missing_unsafe_diagnostic_with_safe_intrinsic() {
         check_diagnostics(
             r#"
+#[rustc_intrinsic]
+pub fn bitreverse(x: u32) -> u32; // Safe intrinsic
+#[rustc_intrinsic]
+pub unsafe fn floorf32(x: f32) -> f32; // Unsafe intrinsic
+
+fn main() {
+    let _ = bitreverse(12);
+    let _ = floorf32(12.0);
+          //^^^^^^^^^^^^^^💡 error: call to unsafe function is unsafe and requires an unsafe function or block
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_missing_unsafe_diagnostic_with_legacy_safe_intrinsic() {
+        check_diagnostics(
+            r#"
 extern "rust-intrinsic" {
     #[rustc_safe_intrinsic]
     pub fn bitreverse(x: u32) -> u32; // Safe intrinsic