diff --git a/cabal.project b/cabal.project
index 6f26b3828..b454dd7d6 100644
--- a/cabal.project
+++ b/cabal.project
@@ -22,6 +22,9 @@ packages:
 
 extra-packages: Cabal, process
 
+if impl(ghc < 9.8)
+  constraints: interpolatedstring-perl6:setup.time source
+
 program-options
   ghc-options: -Werror