used better condition for checking intrinsics

Author: vayunbiyani

compiler/rustc_passes/src/liveness.rs

@@ -1521,8 +1521,8 @@ impl<'tcx> Liveness<'_, 'tcx> {
     }
 
     fn warn_about_unused_args(&self, body: &hir::Body<'_>, entry_ln: LiveNode) {
-        let fn_attrs = self.ir.tcx.hir().attrs(body.value.hir_id);
-        let is_intrinsic = fn_attrs.iter().any(|attr| attr.has_name(sym::rustc_intrinsic));
+        let is_intrinsic_with_no_body = self.ir.tcx.intrinsic(body.value.hir_id.owner.def_id)?.must_be_overridden();
+
         if is_intrinsic {
             let has_body = match &body.value.kind {
                 rustc_hir::ExprKind::Block(block, _) => !block.stmts.is_empty() || block.expr.is_some(),