diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 28f40eb..69c4639 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -15,6 +15,8 @@ jobs:
           - ghc: '8.6.5'
           - os: 'windows-latest'
 
+    runs-on: ${{ matrix.os }}
+
     steps:
       - uses: actions/checkout@v2