diff --git a/project/HouseRulesPlugin.scala b/project/HouseRulesPlugin.scala
index a7b47999b..c6e617fc0 100644
--- a/project/HouseRulesPlugin.scala
+++ b/project/HouseRulesPlugin.scala
@@ -14,15 +14,15 @@ object HouseRulesPlugin extends AutoPlugin {
     scalacOptions += "-language:implicitConversions",
     scalacOptions ++= "-Xfuture".ifScala213OrMinus.value.toList,
     scalacOptions ++= "-Xlint".ifScala2.value.toList,
-    scalacOptions ++= "-Werror"
-      .ifScala3x(_ => {
+    scalacOptions ++= {
+      if (
         sys.props.get("sbt.build.fatal") match {
           case Some(_) => java.lang.Boolean.getBoolean("sbt.build.fatal")
           case _       => true
         }
-      })
-      .value
-      .toList,
+      ) List("-Werror")
+      else Nil
+    },
     scalacOptions ++= "-Yinline-warnings".ifScala211OrMinus.value.toList,
     scalacOptions ++= "-Yno-adapted-args".ifScala212OrMinus.value.toList,
     scalacOptions ++= "-Ywarn-dead-code".ifScala2.value.toList,