diff --git a/buildSrc/build.gradle.kts b/buildSrc/build.gradle.kts
index 663f4bfe4e5..1b73680ff15 100644
--- a/buildSrc/build.gradle.kts
+++ b/buildSrc/build.gradle.kts
@@ -199,6 +199,7 @@ java {
 }
 
 tasks.withType<KotlinCompile>().configureEach {
+    kotlinOptions.allWarningsAsErrors = true
     kotlinOptions.freeCompilerArgs += listOf(
         "-Xopt-in=kotlin.RequiresOptIn",
         "-Xskip-runtime-version-check",
@@ -262,4 +263,4 @@ gradlePlugin {
             implementationClass = "org.jetbrains.kotlin.NativeInteropPlugin"
         }
     }
-}
\ No newline at end of file
+}
diff --git a/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/Utils.kt b/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/Utils.kt
index 73cd5beabb3..fc817dc4d45 100644
--- a/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/Utils.kt
+++ b/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/Utils.kt
@@ -135,9 +135,9 @@ val Project.globalTestArgs: List<String>
 val Project.testTargetSupportsCodeCoverage: Boolean
     get() = this.testTarget.supportsCodeCoverage()
 
-fun projectOrFiles(proj:Project, notation: String):Any?{
+fun projectOrFiles(proj: Project, notation: String): Any? {
     val propertyMapper = proj.findProperty("notationMapping") ?: return proj.project(notation)
-    val mapping = (propertyMapper as? Map<String, String>)?.get(notation) ?: return proj.project(notation)
+    val mapping = (propertyMapper as? Map<*, *>)?.get(notation) as? String ?: return proj.project(notation)
     return proj.files(mapping).also {
         proj.logger.info("MAPPING: $notation -> ${it.asPath}")
     }