--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/test/TableGen/subst2.td	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,16 @@
+// RUN: llvm-tblgen %s | FileCheck %s
+// XFAIL: vg_leak
+// CHECK: No subst
+// CHECK: No foo
+// CHECK: RECURSE foo
+
+class Recurse<string t> {
+  string Text = t;
+}
+
+class Text<string text> : 
+  Recurse<!subst("RECURSE", "RECURSE", !subst("NORECURSE", "foo", text))>;
+
+def Ok1 : Text<"No subst">;
+def Ok2 : Text<"No NORECURSE">;
+def Trouble : Text<"RECURSE NORECURSE">;