[FIR2IR] Generate @FlexibleMutability annotation on IR types if needed

core/compiler.common/src/org/jetbrains/kotlin/name/StandardClassIds.kt

@@ -174,6 +174,7 @@ object StandardClassIds {
 
         val RawTypeAnnotation = "RawType".internalIrId()
         val FlexibleNullability = "FlexibleNullability".internalIrId()
+        val FlexibleMutability = "FlexibleMutability".internalIrId()
         val EnhancedNullability = "EnhancedNullability".jvmInternalId()
 
         val InlineOnly = "InlineOnly".internalId()

core/compiler.common/src/org/jetbrains/kotlin/types/CommonFlexibleTypeBoundsChecker.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2023 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.types
+
+import org.jetbrains.kotlin.builtins.StandardNames.FqNames
+import org.jetbrains.kotlin.name.FqName
+
+object CommonFlexibleTypeBoundsChecker {
+    val baseTypesToMutableEquivalent = mapOf(
+        FqNames.iterable to FqNames.mutableIterable,
+        FqNames.iterator to FqNames.mutableIterator,
+        FqNames.listIterator to FqNames.mutableListIterator,
+        FqNames.list to FqNames.mutableList,
+        FqNames.collection to FqNames.mutableCollection,
+        FqNames.set to FqNames.mutableSet,
+        FqNames.map to FqNames.mutableMap,
+        FqNames.mapEntry to FqNames.mutableMapEntry
+    )
+    val mutableToBaseMap = baseTypesToMutableEquivalent.entries.associateBy({ it.value }) { it.key }
+
+    fun getBaseBoundFqNameByMutability(fqName: FqName): FqName? =
+        if (fqName in baseTypesToMutableEquivalent) fqName
+        else mutableToBaseMap[fqName]
+}