diff --git a/components/HaskellTools.dhall b/components/HaskellTools.dhall
index f790573a223ce20bdf81cd61a766d87aa9c21a97..e13a966f26a70d3c686288820497a91fefc7ebb1 100644
--- a/components/HaskellTools.dhall
+++ b/components/HaskellTools.dhall
@@ -18,6 +18,7 @@ let
         $CABAL \
           --store-dir=${outDir}/store \
           v2-install \
+          --constraint='alex ^>= 3.2.6' \
           --constraint='happy ^>= 1.20' \
           --with-compiler=$GHC \
           --enable-static \