Fix ICE #68058

Author: JohnTitor

src/librustc_ast_lowering/expr.rs

@@ -202,7 +202,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
             ExprKind::Mac(_) => panic!("Shouldn't exist here"),
         };
 
-        hir::Expr { hir_id: self.lower_node_id(e.id), kind, span: e.span, attrs: e.attrs.clone() }
+        hir::Expr {
+            hir_id: self.lower_node_id(e.id),
+            kind,
+            span: e.span,
+            attrs: e.attrs.iter().map(|a| self.lower_attr(a)).collect::<Vec<_>>().into(),
+        }
     }
 
     fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {

src/test/ui/macros/issue-68058.rs

@@ -0,0 +1,15 @@
+// check-pass
+
+macro_rules! def_target {
+    ($target: expr) => {
+        #[target_feature(enable=$target)]
+        unsafe fn f() {
+            #[target_feature(enable=$target)]
+            ()
+        }
+    };
+}
+
+def_target!("avx2");
+
+fn main() {}