diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/sessions/FirIdeSessionProvider.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/sessions/FirIdeSessionProvider.kt
index f35770f11ac..e766d984ea7 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/sessions/FirIdeSessionProvider.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/sessions/FirIdeSessionProvider.kt
@@ -9,6 +9,7 @@ import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.analysis.api.impl.barebone.annotations.Immutable
 import org.jetbrains.kotlin.analysis.low.level.api.fir.file.builder.ModuleFileCache
 import org.jetbrains.kotlin.analysis.project.structure.KtModule
+import org.jetbrains.kotlin.analysis.project.structure.NoCacheForModuleException
 import org.jetbrains.kotlin.fir.FirModuleData
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.FirSessionProvider
@@ -26,7 +27,8 @@ class LLFirSessionProvider internal constructor(
         moduleToSession[module]
 
     internal fun getModuleCache(module: KtModule): ModuleFileCache =
-        moduleToSession.getValue(module).cache
+        moduleToSession[module]?.cache
+            ?: throw NoCacheForModuleException(module, moduleToSession.keys)
 
     val allSessions: Collection<LLFirModuleSession>
         get() = moduleToSession.values
diff --git a/analysis/project-structure/src/org/jetbrains/kotlin/analysis/project/structure/NoCacheForModuleException.kt b/analysis/project-structure/src/org/jetbrains/kotlin/analysis/project/structure/NoCacheForModuleException.kt
new file mode 100644
index 00000000000..54d937a9cb9
--- /dev/null
+++ b/analysis/project-structure/src/org/jetbrains/kotlin/analysis/project/structure/NoCacheForModuleException.kt
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.analysis.project.structure
+
+/**
+ * Exception to signal that no [org.jetbrains.kotlin.analysis.low.level.api.fir.file.builder.ModuleFileCache] was
+ * found for [missingModule] by [org.jetbrains.kotlin.analysis.low.level.api.fir.sessions.LLFirSessionProvider].
+ *
+ * TODO: This can be caused by the problem described in KT-51240. When the problem is fixed, this exception will probably become redundant.
+ */
+public class NoCacheForModuleException(
+    private val missingModule: KtModule,
+    private val existingModules: Set<KtModule>
+) : NoSuchElementException() {
+    override val message: String
+        get() = "No cache was found for module '${missingModule.moduleDescription}'! " +
+                "Caches exist for the following modules: ${existingModules.map { it.moduleDescription }}"
+}
\ No newline at end of file
diff --git a/analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/firLightClassUtils.kt b/analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/firLightClassUtils.kt
index ab220786000..769ca4f02a6 100644
--- a/analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/firLightClassUtils.kt
+++ b/analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/firLightClassUtils.kt
@@ -10,6 +10,7 @@ import com.intellij.psi.PsiModifier
 import com.intellij.psi.PsiReferenceList
 import com.intellij.psi.util.CachedValueProvider
 import com.intellij.psi.util.CachedValuesManager
+import org.jetbrains.kotlin.analysis.api.KtAnalysisSession
 import org.jetbrains.kotlin.analysis.providers.createProjectWideOutOfBlockModificationTracker
 import org.jetbrains.kotlin.analysis.api.symbols.*
 import org.jetbrains.kotlin.analysis.api.symbols.markers.KtSymbolWithMembers
@@ -21,6 +22,7 @@ import org.jetbrains.kotlin.analysis.api.types.KtNonErrorClassType
 import org.jetbrains.kotlin.analysis.api.types.KtType
 import org.jetbrains.kotlin.analysis.project.structure.KtSourceModule
 import org.jetbrains.kotlin.analysis.project.structure.getKtModuleOfTypeSafe
+import org.jetbrains.kotlin.analysis.project.structure.NoCacheForModuleException
 import org.jetbrains.kotlin.asJava.builder.LightMemberOriginForDeclaration
 import org.jetbrains.kotlin.asJava.classes.*
 import org.jetbrains.kotlin.asJava.elements.KtLightField
@@ -433,19 +435,39 @@ internal fun KtSymbolWithMembers.createInnerClasses(
     return result
 }
 
-internal fun KtClassOrObject.checkIsInheritor(baseClassOrigin: KtClassOrObject, checkDeep: Boolean): Boolean {
-    return analyseForLightClasses(this) {
-        val subClassSymbol = this@checkIsInheritor.getClassOrObjectSymbol()
-        val superClassSymbol = baseClassOrigin.getClassOrObjectSymbol()
+internal fun KtClassOrObject.checkIsInheritor(superClassOrigin: KtClassOrObject, checkDeep: Boolean): Boolean {
+    val subClassOrigin = this
 
-        if (subClassSymbol == superClassSymbol) return@analyseForLightClasses false
+    fun KtAnalysisSession.check(): Boolean {
+        val subClassSymbol = subClassOrigin.getClassOrObjectSymbol()
+        val superClassSymbol = superClassOrigin.getClassOrObjectSymbol()
 
-        if (checkDeep) {
+        if (subClassSymbol == superClassSymbol) return false
+
+        return if (checkDeep) {
             subClassSymbol.isSubClassOf(superClassSymbol)
         } else {
             subClassSymbol.isDirectSubClassOf(superClassSymbol)
         }
     }
+
+    // Due to the KT-51240 we cannot be sure which PSI element is better to analyse, so we try both.
+    //
+    // We specifically catch NoCacheForModuleException as a sign that LLFirSessionProvider.getModuleCache could not
+    // find a cache for the passed module. This means that `module(subClassOrigin)` does not have `module(superClassOrigin)` as
+    // its dependency, and we should try the other way around.
+    //
+    // Note, however, that the second call might also fail, since the modules can be completely independent.
+    // We can only hope that, since this code is invoked from the light classes, the passed PSI classes are
+    // relatively close to each other syntactically, meaning that there is some dependency between the modules
+    // they reside in.
+    //
+    // TODO: Avoid this hack when KT-51240 is fixed
+    return try {
+        analyseForLightClasses(subClassOrigin) { check() }
+    } catch (e: NoCacheForModuleException) {
+        analyseForLightClasses(superClassOrigin) { check() }
+    }
 }
 
 private val KtSymbolWithTypeParameters.hasReifiedParameters: Boolean