diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/LLFirResolveSessionDepended.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/LLFirResolveSessionDepended.kt
index ba23eb6c2dd..b108aa91898 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/LLFirResolveSessionDepended.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/LLFirResolveSessionDepended.kt
@@ -40,7 +40,6 @@ internal class LLFirResolveSessionDepended(
     override val project: Project get() = originalFirResolveSession.project
     override val useSiteKtModule: KtModule get() = originalFirResolveSession.useSiteKtModule
     override val useSiteFirSession get() = originalFirResolveSession.useSiteFirSession
-    override val isLibrarySession get() = false
 
     private val scopeSessionProviderCache = SoftCachedMap.create<FirSession, LLFirScopeSessionProvider>(
         project,
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/api/LLFirResolveSession.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/api/LLFirResolveSession.kt
index db777e6dbea..5829026f2e2 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/api/LLFirResolveSession.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/api/LLFirResolveSession.kt
@@ -31,8 +31,6 @@ abstract class LLFirResolveSession {
 
     abstract val useSiteKtModule: KtModule
 
-    abstract val isLibrarySession: Boolean
-
     abstract fun getSessionFor(module: KtModule): LLFirSession
 
     abstract fun getScopeSessionFor(firSession: FirSession): ScopeSession
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirLibraryOrLibrarySourceResolvableResolveSession.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirLibraryOrLibrarySourceResolvableResolveSession.kt
index 2db8a6ff35b..56689b63015 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirLibraryOrLibrarySourceResolvableResolveSession.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirLibraryOrLibrarySourceResolvableResolveSession.kt
@@ -22,9 +22,6 @@ internal class LLFirLibraryOrLibrarySourceResolvableResolveSession(
     override val useSiteKtModule: KtModule,
     sessionProvider: LLFirSessionProvider,
 ) : LLFirResolvableResolveSession(sessionProvider) {
-    override val isLibrarySession: Boolean
-        get() = true
-
     override fun getDiagnostics(element: KtElement, filter: DiagnosticCheckerFilter): List<KtPsiDiagnostic> =
         emptyList()
 
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirNotUnderContentRootResolveSession.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirNotUnderContentRootResolveSession.kt
index 35d2eca9597..f26403cf6fa 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirNotUnderContentRootResolveSession.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirNotUnderContentRootResolveSession.kt
@@ -20,9 +20,6 @@ internal class LLFirNotUnderContentRootResolveSession(
     override val useSiteKtModule: KtModule,
     sessionProvider: LLFirSessionProvider,
 ) : LLFirResolvableResolveSession(sessionProvider) {
-    override val isLibrarySession: Boolean
-        get() = false
-
     override fun getDiagnostics(element: KtElement, filter: DiagnosticCheckerFilter): List<KtPsiDiagnostic> =
         emptyList()
 
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirSourceResolveSession.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirSourceResolveSession.kt
index cd724338cf5..6e2de3cbfca 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirSourceResolveSession.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/state/LLFirSourceResolveSession.kt
@@ -24,9 +24,6 @@ internal class LLFirSourceResolveSession(
     override val useSiteKtModule: KtModule,
     sessionProvider: LLFirSessionProvider,
 ) : LLFirResolvableResolveSession(sessionProvider) {
-    override val isLibrarySession: Boolean
-        get() = false
-
     override fun getDiagnostics(element: KtElement, filter: DiagnosticCheckerFilter): List<KtPsiDiagnostic> {
         val moduleComponents = getModuleComponentsForElement(element)
         return moduleComponents.diagnosticsCollector.getDiagnosticsFor(element, filter)
diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/AbstractFirLazyDeclarationResolveTest.kt b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/AbstractFirLazyDeclarationResolveTest.kt
index d66c789531b..1dd01283506 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/AbstractFirLazyDeclarationResolveTest.kt
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/AbstractFirLazyDeclarationResolveTest.kt
@@ -65,7 +65,7 @@ abstract class AbstractFirLazyDeclarationResolveTest : AbstractLowLevelApiSingle
             errorExpressionRenderer = FirErrorExpressionExtendedRenderer(),
         )
         resolveWithClearCaches(ktFile) { firResolveSession ->
-            check(!firResolveSession.isLibrarySession)
+            check(firResolveSession.isSourceSession)
             val declarationToResolve = firResolveSession
                 .getOrBuildFirFile(ktFile)
                 .findResolveMe()
@@ -79,7 +79,7 @@ abstract class AbstractFirLazyDeclarationResolveTest : AbstractLowLevelApiSingle
         }
 
         resolveWithClearCaches(ktFile) { llSession ->
-            check(!llSession.isLibrarySession)
+            check(llSession.isSourceSession)
             val firFile = llSession.getOrBuildFirFile(ktFile)
             firFile.lazyResolveToPhase(FirResolvePhase.BODY_RESOLVE)
             resultBuilder.append("\nFILE RAW TO BODY:\n")
diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/AbstractFirContextCollectionTest.kt b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/AbstractFirContextCollectionTest.kt
index 209907c4543..f3e95056d3e 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/AbstractFirContextCollectionTest.kt
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/AbstractFirContextCollectionTest.kt
@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.fir.declarations.FirDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirFile
 import org.jetbrains.kotlin.fir.resolve.ImplicitReceiverStack
 import org.jetbrains.kotlin.fir.resolve.SessionHolderImpl
-import org.jetbrains.kotlin.analysis.low.level.api.fir.state.LLFirSourceResolveSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.DiagnosticCheckerFilter
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.getDiagnostics
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.getOrBuildFirFile
@@ -23,6 +22,7 @@ import org.jetbrains.kotlin.analysis.low.level.api.fir.file.structure.FileStruct
 import org.jetbrains.kotlin.analysis.low.level.api.fir.file.structure.NonReanalyzableDeclarationStructureElement
 import org.jetbrains.kotlin.analysis.low.level.api.fir.file.structure.ReanalyzableStructureElement
 import org.jetbrains.kotlin.analysis.low.level.api.fir.file.structure.RootStructureElement
+import org.jetbrains.kotlin.analysis.low.level.api.fir.isSourceSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.name
 import org.jetbrains.kotlin.analysis.low.level.api.fir.resolveWithClearCaches
 import org.jetbrains.kotlin.analysis.low.level.api.fir.sessions.LLFirResolvableModuleSession
@@ -46,7 +46,7 @@ abstract class AbstractFirContextCollectionTest : AbstractLowLevelApiSingleFileT
                 register(BeforeElementDiagnosticCollectionHandler::class, handler)
             }
         ) { firResolveSession ->
-            check(!firResolveSession.isLibrarySession)
+            check(firResolveSession.isSourceSession)
 
             val session = firResolveSession.getSessionFor(ktFile.getKtModule()) as LLFirResolvableModuleSession
             val fileStructureCache = session.moduleComponents.fileStructureCache
diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/file/structure/AbstractFileStructureTest.kt b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/file/structure/AbstractFileStructureTest.kt
index fa18f9a08ce..baf45a96336 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/file/structure/AbstractFileStructureTest.kt
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/file/structure/AbstractFileStructureTest.kt
@@ -11,8 +11,8 @@ import com.intellij.psi.PsiElementVisitor
 import com.intellij.psi.PsiErrorElement
 import com.intellij.psi.impl.source.tree.LeafPsiElement
 import com.intellij.psi.util.PsiTreeUtil
-import org.jetbrains.kotlin.analysis.low.level.api.fir.state.LLFirSourceResolveSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.getFirResolveSession
+import org.jetbrains.kotlin.analysis.low.level.api.fir.isSourceSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.sessions.LLFirResolvableModuleSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.test.base.AbstractLowLevelApiSingleFileTest
 import org.jetbrains.kotlin.analysis.low.level.api.fir.test.configurators.AnalysisApiFirOutOfContentRootTestConfigurator
@@ -100,7 +100,7 @@ abstract class AbstractFileStructureTest : AbstractLowLevelApiSingleFileTest() {
 
     private fun KtFile.getFileStructure(): FileStructure {
         val moduleFirResolveSession = getFirResolveSession()
-        check(!moduleFirResolveSession.isLibrarySession)
+        check(moduleFirResolveSession.isSourceSession)
         val session = moduleFirResolveSession.getSessionFor(getKtModule()) as LLFirResolvableModuleSession
         return session.moduleComponents.fileStructureCache.getFileStructure(this)
     }
diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/firTestUtils.kt b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/firTestUtils.kt
index ac11f019cbe..10b8623c859 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/firTestUtils.kt
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/firTestUtils.kt
@@ -7,6 +7,8 @@ package org.jetbrains.kotlin.analysis.low.level.api.fir
 
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.LLFirResolveSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.sessions.LLFirSession
+import org.jetbrains.kotlin.analysis.low.level.api.fir.state.LLFirNotUnderContentRootResolveSession
+import org.jetbrains.kotlin.analysis.low.level.api.fir.state.LLFirSourceResolveSession
 import org.jetbrains.kotlin.analysis.project.structure.getKtModule
 import org.jetbrains.kotlin.fir.FirElement
 import org.jetbrains.kotlin.fir.declarations.FirDeclaration
@@ -43,3 +45,11 @@ internal inline fun <R> resolveWithClearCaches(
     val firResolveSession = createFirResolveSessionForNoCaching(context.getKtModule(project), project, configureSession)
     return action(firResolveSession)
 }
+
+internal val LLFirResolveSession.isSourceSession: Boolean
+    get() {
+        return when (this) {
+            is LLFirSourceResolveSession, is LLFirNotUnderContentRootResolveSession -> true
+            else -> false
+        }
+    }
\ No newline at end of file