add missing output for ui test

diff --git a/src/test/ui/issue-50403.stderr b/src/test/ui/issue-50403.stderr
new file mode 100644 (file)
index 0000000..f2871c7
--- /dev/null
+++ b/src/test/ui/issue-50403.stderr
@@ -0,0 +1,8 @@
+error: concat_idents! takes 1 or more arguments.
+  --> $DIR/issue-50403.rs:14:13
+   |
+LL |     let x = concat_idents!(); //~ ERROR concat_idents! takes 1 or more arguments
+   |             ^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+