diff --git a/.ci/gitlab/branch.yaml b/.ci/gitlab/branch.yaml
index de55ad3..ba6a7ac 100644
--- a/.ci/gitlab/branch.yaml
+++ b/.ci/gitlab/branch.yaml
@@ -61,16 +61,19 @@ stack-build:
     - export THREADS=$(./.ci/effective_cpus.sh)
     - tar -cf - /root/.stack | zstd -T$THREADS -3 > cache.tar.zst
 
-#nix-build:
-#  image: nixos/nix:2.10.1
-#  needs: []
-#  stage: test
-#  before_script:
-#   - nix-env -i gawk
-#  script:
-#    - nix-build -j$(./.ci/effective_cpus.sh) --log-format raw --max-silent-time 3600
-#  tags:
-#    - local
+nix-build:
+  image: nixos/nix:2.10.1
+  needs: []
+  stage: test
+  rules:
+    - if: $CLASH_BRANCH == "release"
+  before_script:
+    - nix-env -i gawk
+    - export
+  script:
+    - nix-build -j$(./.ci/effective_cpus.sh) --log-format raw --max-silent-time 3600
+  tags:
+    - local
 
 haddock:
   extends: .common-local
diff --git a/.gitignore b/.gitignore
index f295cdd..430c734 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 dist/
 build/
+result/
 dist-newstyle/
 .stack-work/
 stack.yaml.lock
diff --git a/nix/sources.json b/nix/sources.json
index 2902c90..79efc1d 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -1,14 +1,14 @@
 {
     "clash-compiler": {
-        "branch": "master",
+        "branch": "1.8",
         "description": "Haskell to VHDL/Verilog/SystemVerilog compiler",
         "homepage": "https://clash-lang.org/",
         "owner": "clash-lang",
         "repo": "clash-compiler",
-        "rev": "b14ff0ef2ccfad8854210a9035e9db1e32b3be07",
-        "sha256": "00gq0v4fi2dy13xchllxxhhjfpvvj0ig8cgp5y65c7zb7qw5b30y",
+        "rev": "3f5dc67c0e526e43a4dd88eb3902e39ed512c166",
+        "sha256": "022rwif8xkaabw0j3arhyj0hswmh3vq2nx1bbz8rbkp05jm4psgg",
         "type": "tarball",
-        "url": "https://github.com/clash-lang/clash-compiler/archive/b14ff0ef2ccfad8854210a9035e9db1e32b3be07.tar.gz",
+        "url": "https://github.com/clash-lang/clash-compiler/archive/3f5dc67c0e526e43a4dd88eb3902e39ed512c166.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
         "version": "1.8.1"
     },