diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f5ffa0029..4d0fb339b 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -101,7 +101,7 @@ jobs:
     - name: Run check
       env: ${{ matrix.env }}
       run: |
-        if [[ ! -z "$PYPY_VERSION" ]]; then
+        if ([[ ! -z "$PYPY_VERSION" ]]); then
           export PYPY_VERSION="pypy$PYPY_VERSION-linux64"
           wget "https://downloads.python.org/pypy/${PYPY_VERSION}.tar.bz2"
           tar -jxf ${PYPY_VERSION}.tar.bz2