Review fixes:

Use `StorageManager.createLazyValue` instead of default lazy delegate
Introduce `initialize` method instead of exposing type parameters

compiler/frontend/src/org/jetbrains/kotlin/psi/synthetics/SyntheticClassOrObjectDescriptor.kt

@@ -50,15 +50,21 @@ class SyntheticClassOrObjectDescriptor(
     val syntheticDeclaration: KtPureClassOrObject = SyntheticDeclaration(parentClassOrObject, name.asString())
 
     private val thisDescriptor: SyntheticClassOrObjectDescriptor get() = this // code readability
-    var typeParameters: List<TypeParameterDescriptor> = emptyList()
 
+    private lateinit var typeParameters: List<TypeParameterDescriptor>
     private val typeConstructor = SyntheticTypeConstructor(c.storageManager)
     private val resolutionScopesSupport = ClassResolutionScopesSupport(thisDescriptor, c.storageManager, c.languageVersionSettings, { outerScope })
     private val syntheticSupertypes =
         mutableListOf<KotlinType>().apply { c.syntheticResolveExtension.addSyntheticSupertypes(thisDescriptor, this) }
     private val unsubstitutedMemberScope =
         LazyClassMemberScope(c, SyntheticClassMemberDeclarationProvider(syntheticDeclaration), this, c.trace)
-    private val _unsubstitutedPrimaryConstructor by lazy { createUnsubstitutedPrimaryConstructor(constructorVisibility) }
+    private val _unsubstitutedPrimaryConstructor =
+        c.storageManager.createLazyValue { createUnsubstitutedPrimaryConstructor(constructorVisibility) }
+
+    @JvmOverloads
+    fun initialize(typeParameters: List<TypeParameterDescriptor> = emptyList()) {
+        this.typeParameters = typeParameters
+    }
 
     override val annotations: Annotations get() = Annotations.EMPTY
 
@@ -74,8 +80,8 @@ class SyntheticClassOrObjectDescriptor(
 
     override fun getCompanionObjectDescriptor(): ClassDescriptorWithResolutionScopes? = null
     override fun getTypeConstructor(): TypeConstructor = typeConstructor
-    override fun getUnsubstitutedPrimaryConstructor() = _unsubstitutedPrimaryConstructor
+    override fun getUnsubstitutedPrimaryConstructor() = _unsubstitutedPrimaryConstructor()
-    override fun getConstructors() = listOf(_unsubstitutedPrimaryConstructor)
+    override fun getConstructors() = listOf(_unsubstitutedPrimaryConstructor())
     override fun getDeclaredTypeParameters() = typeParameters
     override fun getStaticScope() = MemberScope.Empty
     override fun getUnsubstitutedMemberScope() = unsubstitutedMemberScope

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyClassDescriptor.java

@@ -435,11 +435,13 @@ public class LazyClassDescriptor extends ClassDescriptorBase implements ClassDes
         Name syntheticCompanionName = c.getSyntheticResolveExtension().getSyntheticCompanionObjectNameIfNeeded(this);
         if (syntheticCompanionName == null)
             return null;
-        return new SyntheticClassOrObjectDescriptor(c,
+        SyntheticClassOrObjectDescriptor companionDescriptor = new SyntheticClassOrObjectDescriptor(c,
                 /* parentClassOrObject= */ classOrObject,
                 this, syntheticCompanionName, getSource(),
                 /* outerScope= */ getOuterScope(),
                 Modality.FINAL, PUBLIC, PRIVATE, ClassKind.OBJECT, true);
+        companionDescriptor.initialize();
+        return companionDescriptor;
     }
 
     @Nullable