diff --git a/Jenkinsfile b/Jenkinsfile
index 6279071..e82d513 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -14,8 +14,8 @@ pipeline {
         stage("Get implementation lists") {
             steps {
                 script {
-                    r6rs_implementations = sh script: 'sash -L ./snow -L . compile-r7rs.scm --list-r6rs-schemes', returnStdout: true
-                    r7rs_implementations = sh script: 'sash -L ./snow -L . compile-r7rs.scm --list-r7rs-schemes', returnStdout: true
+                    def r6rs_implementations = sh script: 'sash -L ./snow -L . compile-r7rs.scm --list-r6rs-schemes', returnStdout: true
+                    def r7rs_implementations = sh script: 'sash -L ./snow -L . compile-r7rs.scm --list-r7rs-schemes', returnStdout: true
                 }
             }
         }