Introduce api to get nullable ResolverForModule by ModuleInfo

compiler/frontend/src/org/jetbrains/kotlin/analyzer/AnalyzerFacade.kt

@@ -42,6 +42,7 @@ public class ResolverForModule(
 
 abstract class ResolverForProject<M : ModuleInfo> {
     fun resolverForModule(moduleInfo: M): ResolverForModule = resolverForModuleDescriptor(descriptorForModule(moduleInfo))
+    abstract fun tryGetResolverForModule(moduleInfo: M): ResolverForModule?
     abstract fun descriptorForModule(moduleInfo: M): ModuleDescriptor
     abstract fun resolverForModuleDescriptor(descriptor: ModuleDescriptor): ResolverForModule
 
@@ -55,6 +56,7 @@ public class EmptyResolverForProject<M : ModuleInfo> : ResolverForProject<M>() {
     override val name: String
         get() = "Empty resolver"
 
+    override fun tryGetResolverForModule(moduleInfo: M): ResolverForModule? = null
     override fun resolverForModuleDescriptor(descriptor: ModuleDescriptor): ResolverForModule = throw IllegalStateException("$descriptor is not contained in this resolver")
     override fun descriptorForModule(moduleInfo: M) = throw IllegalStateException("Should not be called for $moduleInfo")
     override val allModules: Collection<M> = listOf()
@@ -65,20 +67,23 @@ public class ResolverForProjectImpl<M : ModuleInfo>(
         val descriptorByModule: Map<M, ModuleDescriptorImpl>,
         val delegateResolver: ResolverForProject<M> = EmptyResolverForProject()
 ) : ResolverForProject<M>() {
-    val resolverByModuleDescriptor: MutableMap<ModuleDescriptor, () -> ResolverForModule> = HashMap()
+    override fun tryGetResolverForModule(moduleInfo: M): ResolverForModule? {
+        if (!isCorrectModuleInfo(moduleInfo)) {
+            return null
+        }
+        return resolverForModuleDescriptor(doGetDescriptorForModule(moduleInfo))
+    }
+
+    internal val resolverByModuleDescriptor: MutableMap<ModuleDescriptor, () -> ResolverForModule> = HashMap()
 
     override val allModules: Collection<M> by lazy {
-        (descriptorByModule.keySet() + delegateResolver.allModules).toSet()
+        (descriptorByModule.keys + delegateResolver.allModules).toSet()
     }
 
     override val name: String
         get() = "Resolver for '$debugName'"
 
-    private fun assertCorrectModuleInfo(moduleInfo: M) {
-        if (moduleInfo !in allModules) {
-            throw AssertionError("$name does not know how to resolve $moduleInfo")
-        }
-    }
+    private fun isCorrectModuleInfo(moduleInfo: M) = moduleInfo in allModules
 
     override fun resolverForModuleDescriptor(descriptor: ModuleDescriptor): ResolverForModule {
         val computation = resolverByModuleDescriptor[descriptor] ?: return delegateResolver.resolverForModuleDescriptor(descriptor)
@@ -86,7 +91,13 @@ public class ResolverForProjectImpl<M : ModuleInfo>(
     }
 
     override fun descriptorForModule(moduleInfo: M): ModuleDescriptorImpl {
-        assertCorrectModuleInfo(moduleInfo)
+        if (!isCorrectModuleInfo(moduleInfo)) {
+            throw AssertionError("$name does not know how to resolve $moduleInfo")
+        }
+        return doGetDescriptorForModule(moduleInfo)
+    }
+
+    private fun doGetDescriptorForModule(moduleInfo: M): ModuleDescriptorImpl {
         return descriptorByModule[moduleInfo] ?: return delegateResolver.descriptorForModule(moduleInfo) as ModuleDescriptorImpl
     }
 }