diff --git a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirCompilerFacility.kt b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirCompilerFacility.kt
index 341462dc79a..d329133244b 100644
--- a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirCompilerFacility.kt
+++ b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirCompilerFacility.kt
@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.analysis.api.components.KtCompilerTarget
 import org.jetbrains.kotlin.analysis.api.diagnostics.KtDiagnostic
 import org.jetbrains.kotlin.analysis.api.fir.KtFirAnalysisSession
 import org.jetbrains.kotlin.analysis.api.impl.base.util.KtCompiledFileForOutputFile
+import org.jetbrains.kotlin.analysis.low.level.api.fir.LLFirInternals
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.DiagnosticCheckerFilter
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.LLFirResolveSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.collectDiagnosticsForFile
@@ -229,6 +230,7 @@ internal class KtFirCompilerFacility(
         val injectedValueProvider: InjectedSymbolProvider
     )
 
+    @OptIn(LLFirInternals::class)
     private fun computeCodeFragmentMappings(
         mainKtFile: KtFile,
         mainFirFile: FirFile,
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/declarationUtils.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/declarationUtils.kt
index 8186b27aab7..f2537d92d01 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/declarationUtils.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/declarationUtils.kt
@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.analysis.low.level.api.fir.util
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiFile
 import org.jetbrains.kotlin.analysis.api.KtAnalysisApiInternals
+import org.jetbrains.kotlin.analysis.low.level.api.fir.LLFirInternals
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.LLFirResolveSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.element.builder.canBePartOfParentDeclaration
 import org.jetbrains.kotlin.analysis.low.level.api.fir.element.builder.containingDeclaration
@@ -197,6 +198,7 @@ private fun KtClassLikeDeclaration.findFir(provider: FirProvider): FirClassLikeD
     }
 }
 
+@LLFirInternals
 val FirFile.codeFragment: FirCodeFragment
     get() {
         return declarations.singleOrNull() as? FirCodeFragment