diff --git a/cabal.project b/cabal.project
index e732b7522..b70ea8492 100644
--- a/cabal.project
+++ b/cabal.project
@@ -1 +1,17 @@
-packages: ./dhall ./dhall-bash ./dhall-json ./dhall-yaml ./dhall-nix ./dhall-docs ./dhall-openapi ./dhall-nixpkgs ./dhall-csv ./dhall-toml ./dhall-lsp-server
+packages:
+  ./dhall
+  ./dhall-bash
+  ./dhall-csv
+  ./dhall-docs
+  ./dhall-json
+  ./dhall-lsp-server
+  ./dhall-nix
+  ./dhall-nixpkgs
+  ./dhall-openapi
+  ./dhall-toml
+  ./dhall-yaml
+
+source-repository-package
+  type: git
+  location: https://github.com/haskell-nix/hnix.git
+  tag: 2adbc502e62e755ca0372c913e6278ebe564d7d2