diff --git a/build.sbt b/build.sbt
index 3cd53efa7..12a907c1c 100644
--- a/build.sbt
+++ b/build.sbt
@@ -50,6 +50,9 @@ inThisBuild(
   )
 )
 
+def inferOverrideFor2_13(version: String): Seq[String] =
+  if (version.startsWith("2.13")) Seq("-Xsource-features:infer-override") else Nil
+
 def disableMissingInterpolatorWarning(options: Seq[String]): Seq[String] =
   options.map { opt =>
     if (opt.startsWith("-Xlint")) opt + ",-missing-interpolator" else opt
@@ -134,6 +137,7 @@ lazy val core = crossProject(JSPlatform, JVMPlatform)
       "org.scalameta" %%% "munit"     % versions.munit % "test",
       "org.typelevel" %%% "cats-core" % versions.catsCore
     ),
+    scalacOptions ++= inferOverrideFor2_13(scalaVersion.value),
     Test / scalacOptions ~= disableMissingInterpolatorWarning
   )
   .jvmSettings(
diff --git a/core/shared/src/main/scala/laika/internal/parse/hocon/ConfigResolver.scala b/core/shared/src/main/scala/laika/internal/parse/hocon/ConfigResolver.scala
index ade10c27b..bc983a1a3 100644
--- a/core/shared/src/main/scala/laika/internal/parse/hocon/ConfigResolver.scala
+++ b/core/shared/src/main/scala/laika/internal/parse/hocon/ConfigResolver.scala
@@ -296,7 +296,7 @@ private[laika] object ConfigResolver {
       obj.values.groupBy(_.key.getOrElse(Key.root)).mapValuesStrict(_.map(_.value)).toSeq.map {
         case (key, values) =>
           val merged = values.reduce(mergeValues(key)) match {
-            case obj: ObjectBuilderValue => mergeObjects(obj)
+            case obv: ObjectBuilderValue => mergeObjects(obv)
             case other                   => other
           }
           BuilderField(key, merged)
@@ -373,8 +373,8 @@ private[laika] object ConfigResolver {
             extract(field + "." + index, arrValue)
           }
           if (nested.isEmpty) wrap(failure) else nested
-        case InvalidBuilderValue(obj: ObjectBuilderValue, failure)   =>
-          val nested = extractErrors(obj)
+        case InvalidBuilderValue(obv: ObjectBuilderValue, failure)   =>
+          val nested = extractErrors(obv)
           if (nested.isEmpty) wrap(failure) else nested
         case InvalidBuilderValue(_, failure)                         => wrap(failure)
         case incl: IncludeBuilderValue                               =>