diff --git a/idea/src/org/jetbrains/kotlin/idea/injection/KotlinLanguageInjector.kt b/idea/src/org/jetbrains/kotlin/idea/injection/KotlinLanguageInjector.kt
index b26b21bd3f2..92ab00fee0f 100644
--- a/idea/src/org/jetbrains/kotlin/idea/injection/KotlinLanguageInjector.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/injection/KotlinLanguageInjector.kt
@@ -29,6 +29,7 @@ import org.intellij.plugins.intelliLang.inject.InjectorUtils
 import org.intellij.plugins.intelliLang.inject.config.BaseInjection
 import org.intellij.plugins.intelliLang.inject.java.JavaLanguageInjectionSupport
 import org.intellij.plugins.intelliLang.util.AnnotationUtilEx
+import org.jetbrains.kotlin.idea.util.ProjectRootsUtil
 import org.jetbrains.kotlin.idea.util.findAnnotation
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
@@ -43,6 +44,8 @@ class KotlinLanguageInjector : LanguageInjector {
         if (!host.isValidHost) return
         val ktHost: KtElement = host as? KtElement ?: return
 
+        if (!ProjectRootsUtil.isInProjectOrLibSource(ktHost)) return
+
         val injectionInfo = findInjectionInfo(host) ?: return
 
         val language = InjectorUtils.getLanguageByString(injectionInfo.languageId) ?: return