Recreate module descriptors for affected modules only on a change

core/descriptors/src/org/jetbrains/kotlin/descriptors/ModuleDescriptor.kt

@@ -48,4 +48,6 @@ interface ModuleDescriptor : DeclarationDescriptor {
     class Capability<T>(val name: String) {
         override fun toString() = name
     }
+
+    val isValid: Boolean
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/ModuleDescriptorImpl.kt

@@ -47,6 +47,14 @@ class ModuleDescriptorImpl @JvmOverloads constructor(
     private var dependencies: ModuleDependencies? = null
     private var packageFragmentProviderForModuleContent: PackageFragmentProvider? = null
 
+    override var isValid: Boolean = true
+
+    private fun assertValid() {
+        if (!isValid) {
+            throw IllegalStateException("Accessing invalid module descriptor $this")
+        }
+    }
+
     private val packages = storageManager.createMemoizedFunction<FqName, PackageViewDescriptor> {
         fqName: FqName -> LazyPackageViewDescriptorImpl(this, fqName, storageManager)
     }
@@ -60,9 +68,13 @@ class ModuleDescriptorImpl @JvmOverloads constructor(
     override val allImplementingModules: Set<ModuleDescriptor>
         get() = this.dependencies.sure { "Dependencies of module $id were not set" }.allImplementingModules
 
-    override fun getPackage(fqName: FqName): PackageViewDescriptor = packages(fqName)
+    override fun getPackage(fqName: FqName): PackageViewDescriptor {
+        assertValid()
+        return packages(fqName)
+    }
 
     override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName> {
+        assertValid()
         return packageFragmentProvider.getSubPackagesOf(fqName, nameFilter)
     }
 
@@ -117,7 +129,10 @@ class ModuleDescriptorImpl @JvmOverloads constructor(
     }
 
     val packageFragmentProvider: PackageFragmentProvider
-        get() = packageFragmentProviderForWholeModuleWithDependencies
+        get() {
+            assertValid()
+            return packageFragmentProviderForWholeModuleWithDependencies
+        }
 
     @Suppress("UNCHECKED_CAST")
     override fun <T> getCapability(capability: ModuleDescriptor.Capability<T>) = capabilities[capability] as? T

core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java

@@ -122,6 +122,11 @@ public class ErrorUtils {
             public KotlinBuiltIns getBuiltIns() {
                 return DefaultBuiltIns.getInstance();
             }
+
+            @Override
+            public boolean isValid() {
+                return false;
+            }
         };
     }