1 files changed, 34 insertions, 0 deletions
diff --git a/tests/ui/proc-macro/issue-79242-slow-retokenize-check.rs b/tests/ui/proc-macro/issue-79242-slow-retokenize-check.rs
new file mode 100644
index 000000000..b68f19c5d
--- /dev/null
+++ b/tests/ui/proc-macro/issue-79242-slow-retokenize-check.rs
@@ -0,0 +1,34 @@
+// check-pass
+// aux-build:issue-79242.rs
+
+// Regression test for issue #79242
+// Tests that compilation time doesn't blow up for a proc-macro
+// invocation with deeply nested nonterminals
+
+#![allow(unused)]
+
+extern crate issue_79242;
+
+macro_rules! declare_nats {
+    ($prev:ty) => {};
+    ($prev:ty, $n:literal$(, $tail:literal)*) => {
+
+        issue_79242::dummy! {
+            $prev
+        }
+
+        declare_nats!(Option<$prev>$(, $tail)*);
+    };
+    (0, $($n:literal),+) => {
+        pub struct N0;
+        declare_nats!(N0, $($n),+);
+    };
+}
+
+declare_nats! {
+    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+    17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28
+}
+
+
+fn main() {}